Ref. Ares(2018)2019372 - 16/04/2018
Ref. Ares(2020)4498708 - 31/08/2020
Life Cycle
Assessment of
grocery carrier bags
Environmental Project
no. 1985
February 2018
Publisher: The Danish Environmental Protection Agency
Editors: Valentina Bisinella, Paola Federica Albizzati,
Thomas Fruergaard Astrup, Anders Damgaard
The Danish Environmental Protection Agency publishes reports and papers about research and development projects
within the environmental sector, financed by the Agency. The contents of this publication do not necessarily represent
the official views of the Danish Environmental Protection Agency. By publishing this report, the Danish Environmental
Protection Agency expresses that the content represents an important contribution to the related discourse on Danish
environmental policy.
Sources must be acknowledged.
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Danish Environmental Protection Agency / LCA of grocery carrier bags
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Contents
Contents
3
Executive summary – Dansk
5
Executive summary - English
13
Preface
20
List of Abbreviations
21
Key definitions
22
1.
Introduction and objectives
23
1.1
Background
23
1.2
Aim of the study
23
2.
Carrier bags
25
2.1
Carrier bag types
25
2.2
Carrier bags available in Denmark
28
3.
LCA Methodology
31
3.1
LCA goal definition
31
3.2
Functional unit
31
3.2.1
Reference flow
33
3.3
System boundaries
34
3.4
Modelling approach and allocation of multi-functionality
34
3.5
Modelling of primary reuse
35
3.6
Modelling of secondary reuse
35
3.7
Modelling tools
37
3.8
LCIA methodology and types of impacts
38
3.9
Data requirements
38
3.9.1
Production and distribution
38
3.9.2
End-of-life
40
3.10
Assumptions
41
3.10.1
Assumptions on missing data
42
3.11
Data quality assessment
44
3.11.1
Critical assumptions
45
3.12
Cut-offs
45
3.13
Limitations
45
3.14
Life Cycle Interpretation
46
3.15
Critical review
47
3.16
Format of the report
47
4.
Scenarios
48
4.1
Carrier bag alternatives
48
4.2
End-of-life scenarios
50
4.2.1
Incineration: EOL1
50
4.2.2
Recycling of material: EOL2
50
4.2.3
Reuse as waste bin bag: EOL3
51
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3
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4.3
Carrier bag scenarios
52
4.3.1
LDPE carrier bags: LDPEavg, LDPEs, LDPEh, LDPErec
52
4.3.2
PP carrier bags: PP, PPwov
52
4.3.3
Recycled PET carrier bags: PETrec
52
4.3.4
Polyester carrier bags: PETpol
52
4.3.5
Starch-complexed biopolymer bags: BP
53
4.3.6
Paper bags: PAP, PAPb
53
4.3.7
Cotton bags: COTorg, COT
53
4.3.8
Composite bags: COM
53
4.3.9
LDPE waste bin bag
53
5.
Life Cycle Impact Assessment
54
5.1
Results for each carrier bag
54
5.1.1
LDPE bags: LDPEavg, LDPEs, LDPEh, LDPErec, W
58
5.1.2
PP bags: PP, PPwov
61
5.1.3
Recycled PET carrier bags: PETrec
62
5.1.4
Polyester bags: PETpol
65
5.1.5
Comparison of fossil plastic carrier bags
65
5.1.6
Biopolymer bags: BP
66
5.1.7
Paper bags: PAP, PAPb
68
5.1.8
Cotton and composite bags: COTorg, COT, COM
69
5.2
Overview
72
6.
Discussion
74
6.1
Identification of the best disposal option for each carrier bag
74
6.2
Which carrier bag provides the lowest environmental impact to fulfil the
function?
76
6.3
How many times should a carrier bag be reused?
79
6.4
Influence on data and assumptions on the results
81
7.
Sensitivity analysis: critical assumptions
84
7.1
Choice of reference flow: rounding
84
7.2
Secondary reuse as a waste bin bag allowed only for LDPE carriers
86
7.3
Recycled LDPE
88
7.4
Final remarks on sensitivity analysis
89
7.4.1
Carrier bag design
90
8.
Conclusions
92
9.
References
94
Appendix A. Life Cycle Inventories (LCIs)
96
Appendix B. Marginal technologies
108
Appendix B.1 Marginal energy technologies
109
Appendix B.2 Marginal materials
111
Appendix C. Additional results
114
Appendix D. Critical review
128
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Danish Environmental Protection Agency / LCA of grocery carrier bags
Executive summary – Dansk
Konceptuel ramme
Dette studie giver en livscyklusvurdering af produktion, brug og bortskaffelse ("vugge til grav")
af indkøbsposer tilgængelige i danske supermarkeder i 2017. Undersøgelsen blev udført af
DTU Miljø i perioden oktober - december 2017.
I øjeblikket tilbyder danske supermarkeder kunderne flere indkøbsposer i forskellige materialer
(såsom genanvendeligt og ikke-genanvendeligt plast, papir og bomuld) designet til at skulle
bruges flere gange inden bortskaffelse. Grundet miljøpåvirkninger fra deres fremstilling, skal
disse flerbrugsposer optimalt genbruges et vist antal gange for at kompensere for miljøpåvirk-
ningerne, hvor antallet afhænger af materialet og design.
Studiet blev bestilt af Miljøstyrelsen med det formål at identificere indkøbsposen med den
bedste miljøpræstation, til brug i danske supermarkeder. Studiet har til formål at identificere et
anbefalet antal genbrug af hver indkøbspose baseret på indkøbsposernes miljøpåvirkninger
under hele livscyklus. Studie tog højde for, at genbrug af indkøbsposerne kan forekomme
både som primær genbrug (hvor indkøbsposen genbruges til samme funktion, som den blev
produceret, dvs. for at transportere dagligvarer fra supermarked til hjem) eller som erstatning
af en skraldepose i affaldsbeholdere (sekundær genbrug).
De følgende indkøbsposer blev undersøgt:
Lavdensitets polyethylen (LDPE), 4 typer; en LDPE indkøbspose med gennemsnitlige vær-
dier, en LDPE indkøbspose med blødt håndtag, an LDPE indkøbspose med fast håndtag og
en LDPE indkøbspose af genanvendt LDPE
Polypropylen (PP), 2 typer: ikke-vævet og vævet;
Genanvendt polyethylenterephthalat (PET);
Polyester (af primære PET-polymerer);
Stivelse-kompleksbundet biopolymer;
Papir, 2 typer: ubleget og bleget;
Bomuld, 2 typer: økologisk og konventionel;
Komposit materiale (jute, PP, bomuld).
En undersøgelse foretaget af DTU Miljø viste, at LDPE-poser er tilgængelige for køb i alle
danske supermarkeder, mens andre typer af indkøbsposer tilbydes som alternativer. Derfor
blev de gennemsnitlige egenskaber ved en LDPE indkøbspose brugt som referencepose i
studiet. Rapporten omhandler kun indkøbsposer til rådighed i danske supermarkeder i 2017,
og omfatter ikke andre typer af poser. Rapporten fokuserer på de miljøpåvirkninger, der er
forbundet med indkøbsposerne, og tager ikke stilling til hvad indførelsen af skatter, kunders
holdninger eller adfærdsmæssige ændringer ville kunne have for studiet. Miljøeffekten af, at
poserne smides som henkastet affald i naturen blev antaget som ubetydelige for danske for-
hold og blev derfor ikke inkluderet i modellen. Undersøgelsen blev kun udført for materialety-
per og poser, der allerede var på markedet. Dette betyder ikke, at andre mere optimale kom-
binationer af materialevalg og posedesign ikke kunne være relevante for fremtidig posepro-
duktion (volumen, genanvendt materiale, bæreevne osv.)
Metodisk ramme
Miljøvurderingen blev udført via livscyklusvurdering (LCA), som er en standardiseret metode,
der tager højde for de potentielle miljøpåvirkninger forbundet med de ressourcer, der er nød-
vendige for at producere, bruge og bortskaffe produktet der evalueres samt mulige emissioner
der kan opstå under produktion og bortskaffelse. Når materiale- og energiressourcer genvin-
des, krediteres systemet med potentielt undgåede emissioner fra primær produktion af de
samme ressourcer. For at sammenligne indkøbsposerne tog vi højde for, hvor mange af de
The Danish Environmental Protection Agency / LCA of grocery carrier bags
5
forskellige poser der var nødvendige for at kunne opfylde den funktion, der bliver leveret af en
LDPE indkøbspose med gennemsnitlige egenskaber, som i studies fastsattes til:
"Transportere indkøb med et gennemsnitligt volumen på 22 liter og en gennemsnitlig
vægt på 12 kg fra et dansk supermarked til hjemmet i 2017 med en (nyindkøbt) ind-
købspose. Indkøbsposen er produceret i Europa og distribueret til Danske supermarke-
der. Efter brug, indsamles og behandles indkøbsposen i det danske affaldshåndte-
ringssystem"
Som vist i Tabel I var to poser nødvendige for at opfylde funktionen i tilfælde af simple LDPE,
recirkulerede LDPE-, biopolymer-, papir- og økologiske bomuldsposer. For disse poser, var
enten den krævede volumen eller vægtkapacitet ikke opfyldt. Poser af økologisk og konventi-
onelt produceret bomuld blev modelleret hver for sig, for at kunne sammenligne forskellene i
resultater for de to materialetyper, da økologisk bomuld har et lavere produktions udbytte end
konventionelt produceret bomuld (Forster et al., 2013). Tabel I viser, at for økologisk bomuld
skal der bruges to indkøbsposer, da volumen af den økologiske bomuldspose ikke var lige så
stort som volumen for reference posen af LDPE.
Tabel I. Forskellige indkøbsposer vurderet i denne LCA og det antal poser der kræves
for at opfylde funktionaliteten leveret af en LDPE indkøbspose med gennemsnitlige
egenskaber.
Reference flow
Indkøbspose materiale
Indkøbspose type
(antal poser der er nødvendige)
Plast
LDPE (gennemsnit)
1 (reference pose)
Plast
LDPE simpel
2
Plast
LDPE fast håndtag
1
Plast
LDPE genanvendt
2
Plast
PP ikke-vævet
1
Plast
PP vævet
1
Plast
PET genanvendt
1
Plast
Polyester
1
Bioplast
Biopolymer
2
Papir
Papir, ubleget
2
Papir
Papir, bleget
2
Tekstil
Bomuld økologisk
2
Tekstil
Bomuld konventionelt
1
Komposit
Jute, PP, bomuld
1
Miljøvurderingen blev for hver indkøbspose udført for forskellige bortskaffelsesmuligheder:
forbrænding (EOL1); genanvendelse (EOL2); og genbrug som skraldepose inden forbrænding
(EOL3). For alle indkøbsposer blev der taget højde for miljøpåvirkningen af produktion (anta-
ges at produceres i Europa), emballage ved fremsendelse til butik, transport til Danmark samt
brug og bortskaffelse (som kunne forekomme i Danmark eller i Europa). Den generelle struktur
af de inkluderede scenarier, og processer der tages i betragtning, er vist i Figur I.
Miljøvurderingen blev udført for en række anbefalede miljøpåvirkninger (Europa-
Kommissionen, 2010): klimaforandringer; ozonnedbrydning; human toksicitet (kræft og ikke-
kræftvirkninger); fotokemisk ozondannelse; ioniserende stråling; partikelforurening; terrestrisk
forsuring; terrestrisk eutrofiering; marin eutrofiering; ferskvands eutrofiering; økosystems toksi-
citet; ressourceforbrug fossilt og abiotisk; samt brug af vandressourcer.
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Danish Environmental Protection Agency / LCA of grocery carrier bags
For hver indkøbspose blev beregnet det antal genbrug der var nødvendigt for at tilsvare refe-
renceposen af LDPE. Dette blev gjort per indkøbspose, livscyklus og påvirkningskategori un-
der forudsætning af, at X gange genbrug af en indkøbspose erstatter en tilsvarende anvendel-
se X gange af referenceposen, dvs. for hver gang en pose genbruges undgås den fulde livs-
cyklus af referenceposen. Et grafisk eksempel for primært genbrug er vist i Figur II. Ved at
tage udgangspunkt i vugge-til-grav LCA-resultatet for alternativ indkøbspose A som LCIA1A og
vugge- til- grav LCA-resultatet for den gennemsnitlige LDPE indkøbspose som LCIALDPE, blev
antallet af genbrugsgange x beregnet som følger:
LCIA
LCIA
A
LDPE
x
LCIALDPE
LCA-studiet er baseret på offentligt tilgængelige livscyklusdata (LCI) og data fra eksisterende
studier af indkøbsposer. I udførelsen af studiet var der nogle databegrænsninger og antagel-
ser, for eksempel med hensyn til valget af referencepose, modellering af materialeproduktio-
nen og indkøbsposeproduktionen. En følsomhedsanalyse blev udført for de kritiske antagelser
og valg der blev foretaget.
Produktion af
embal age
Bortskaffelse
Indsamling
Transport
materiale
embal age
Produktion of
Produktion af
Indkøbspose
Transport
Brug
indkøbspose
materiale
Bortskaffelse
Behandling af
indkøbspose
Indsamling
restprodukter
(EOL1/EOL2/
EOL3)
Figur I. Generel struktur for alle indkøbspose scenarier vurderet i denne LCA. “EOL”
henviser til de tre forskellige bortskaffelses scenarier. EOL1: forbrænding, EO2: genan-
vendelse, EOL3: genbrug som skraldepose.
Genbrug X
Produktion af
Indkøbspose
gange
indkøbspose
A
EOL
(Primær
A
(Primær brug)
genbrug)
Undgået
X gange
Produktion af
Indkøbspose
indkøbspose
LDPE
EOL
LDPE
(Primær brug)
Figur II. Generel modellering af primær genbrug. Eksemplet illustrerer den primære
genbrug X gange af en generisk “indkøbspose A”. Genbruget X gange tillader en und-
gået produktion, brug og bortskaffelse X gange af en reference indkøbspose af LDPE.
1 LCIA = life cycle impact assessment
The Danish Environmental Protection Agency / LCA of grocery carrier bags
7
Resultater og anbefalinger
LCA-undersøgelsen gav en række resultater, som kan være nyttige til optimering af brugen og
bortskaffelsen af indkøbsposer til rådighed for køb i Danmark. Resultaterne refererer til de
reference flows der er præsenteret i Tabel I.
Hvad er den mest fordelagtige bortskaffelsesmulighed for hver type af indkøbspose?
Når indkøbsposen er genbrugt så mange gange som muligt, er det bedre at genbruge
indkøbsposen som en skraldepose, end blot at smide posen i restaffaldet, og dette er bedre
end at aflevere posen til genanvendelse. Genanvendelse kan potentielt give større fordele i
tilfælde af tunge plastposer, såsom poser af PP, PET og polyester. Sekundær genbrug som
skraldepose er mest gavnlig for lette indkøbsposer, såsom poser af LDPE, papir og
biopolymer. Når genbrug som skraldepose ikke er muligt, for eksempel når posen let prikkes
hul i, rives i stykker eller bliver fugtig, som for papir- og biopolymerposer, er forbrænding den
mest foretrukne løsning ud fra et miljømæssigt synspunkt. Tabel II giver et resumé af de
opnåede resultater for hver bærerpose.
Tabel II. Oversigt over den mest foretrukne bortskaffelsesmulighed for hver af de ind-
købsposer, der vurderes.
Indkøbspose materiale
Foretrukken bortskaffelsesmetode efter genbrug som indkøbspose
Plast, LDPE
Genbrug som skraldepose
Plast, PP
Genanvendelse, genbrug som skraldepose hvis muligt, ellers forbrændes
Plast, genanvendt PET
Genanvendelse, genbrug som skraldepose hvis muligt, ellers forbrændes
Plast, polyester PET
Genbrug som skraldepose hvis muligt, ellers forbrændes
Biopolymer
Genbrug som skraldepose hvis muligt, ellers forbrændes
Papir
Genbrug som skraldepose hvis muligt, ellers forbrændes
Tekstil
Genbrug som skraldepose hvis muligt, ellers forbrændes
Komposit
Genbrug som skraldepose hvis muligt, ellers forbrændes
Hvilken indkøbspose giver de laveste miljøpåvirkninger?
Generelt har LDPE-indkøbsposer, som er poser der altid kan købes i danske supermarkeder,
de laveste miljøpåvirkninger for de fleste miljøindikatorer (Tabel III). LDPE-indkøbsposer med
stift håndtag havde den laveste miljøpåvirkning i flertallet af de miljøpåvirknings kategorier der
var inkluderet i dette LCA studie. Indkøbsposer, der kan give en lignende lav miljøpåvirkning
er ublegede papir- og biopolymerposer, men for et lavere antal miljøindikatorer. Såkaldt tunge
indkøbsposer, såsom poser af PP, PET, polyester, bleget papir og tekstilposer, skal
genbruges flere gange for at opveje deres miljøproduktionsomkostninger. For poser af samme
materiale havde vævede PP-indkøbsposer lavere belastning end ikke-vævede PP-poser,
ubleget papir havde lavere påvirkning end bleget papir, og konventionelt bomuld havde lavere
påvirkning end økologisk bomuld.
Hvor mange gange skal indkøbsposer mindst genbruges?
For alle indkøbsposer skal de genbruges så mange gange som muligt før bortskaffelse. Tabel
IV rapporterer antal gange indkøbsposen skal genbruges for at reducere de miljømæssige
konsekvenser, der er forbundet med alle de alternative indkøbsposer i forhold til LDPE-
indkøbsposen. Derfor refererer de tal, der er angivet i Tabel IV, til det mindste antal gange en
pose skal genbruges. Det beregnede antal genbrug varierer, hvis kun én miljøindikator er
observeret eller hvis alle miljøindikatorer tages i betragtning. Det beregnede antal genbrug kan
være i overensstemmelse med den mulige levetid for PP, PET og polyester indkøbsposer,
men kan overstige levetiden for bleget papir-, komposit- og bomuldsposer, især hvis man
tager alle miljøindikatorer i betragtning. For LDPE-indkøbsposer var det nødvendige antal
genbrug forholdsvis ens for de forskellige miljøpåvirkningskategorier.
8 The
Danish Environmental Protection Agency / LCA of grocery carrier bags
Tabel III. Indkøbsposer med den laveste miljøpåvirkning for alle de vurderede miljøindi-
katorer. Rækkefølgen, som poserne er anført i, svarer til placering i forhold til deres
LCA-resultater med lavest påvirkning først. Kun de tre laveste effekter er angivet. Re-
sultaterne refererer til det reference flow der er anført i Tabel I.
Miljøpåvirknings indikator
Indkøbspose med lavest påvirkning
Klimaforandringer
Papir ubleget, biopolymer, LDPE
Ozonnedbrydning
LDPE
Human toksicitet, kræft
Papir ubleget, LDPE
Human toksicitet, ikke-kræft
Komposit, PP, LDPE
Fotokemisk ozondannelse
LDPE
Ioniserende stråling
LDPE
Partikelforurening
LDPE
Terrestrisk forsuring
LDPE
Terrestrisk eutrofiering
LDPE
Ferskvands eutrofiering
LDPE
Marin eutrofiering
PP, LDPE
Økosystems toksicitet
LDPE
Ressourceforbrug, fossilt
Papir ubleget, LDPE
Ressourceforbrug, abiotisk
PP, LDPE
Ressourceforbrug, vandressourcer
LDPE, biopolymer
For indkøbsposer af PP, PET, biopolymer og papir var det nødvendige antal genbrug højere i
nogle kategorier end andre. Slutteligt fandtes det, at det meget høje antal genbrug for ind-
købsposer af bomuld og kompositmateriale primært skyldtes kategorien ozonnedbrydning der
var væsentligt højere end de andre kategorier, for hvilken datasættet for produktion af
bomuldsposen havde en væsentligt højere påvirkning end LDPE-posen.
Følsomhedsanalysen af data og antagelser fremhævede vigtigheden af valget af reference
flow, hvilket var afgørende for det beregnede antal genbrug for poser af økologisk bomuld.
Valget af reference flow afhænger af opfyldelsen af funktionen udtrykt af den funktionelle en-
hed beskrevet ovenfor. Specielt viste resultaterne betydningen af indkøbsposens design, som
bør fokusere på maksimering af volumen og bærekapacitet, samtidig med at mængden af
materiale der anvendes minimeres og dermed også vægten af indkøbsposen.
Vores endelige anbefalinger er følgende2:
LDPE-pose, simpel: Kan genbruges direkte som skraldepose i forhold til klimaforandringer,
skal genbruges mindst 1 gang til indkøb når der tages højde for alle andre indikatorer.
Genbrug som skraldepose, forbrænding.
2 Antallet af gange poserne skal genbruges for "alle indikatorer" henviser til det højeste antal blandt dem,
der beregnes for hver påvirkningskategori. For lette indkøbsposer (LDPE, PP, PET ...) skyldes det høje
antal en gruppe af påvirkningskategorier med samme høje værdier. Omvendt er det for komposit- og
bomuldsposer ozonnedbrydning der er grunden til det meget høje antal gange poserne skal genbruges.
Hvis der ses bort fra ozonnedbrydning, falder det nødvendige antal gange poserne skal genbruges fra 50
til 1400 for konventionel bomuld, fra 150 til 3800 for økologisk bomuld og fra 0 til 740 for kompositmateri-
aleposen hvilket primært skyldes brugen af vandressourcer, men ferskvands- og terrestrisk-eutrofiering
har lignende høje værdier. Resultater for det nødvendige antal gange poserne skal genbruges for hver
påvirkningskategori, minimum-maksimum intervaller og gennemsnitligt antal genbrug fremgår af bilag C.
The Danish Environmental Protection Agency / LCA of grocery carrier bags
9
Tabel IV. Beregnet antal primære genbrug nødvendigt for hver indkøbspose, med den
optimale bortskaffelse af indkøbsposen, for at give den samme miljømæssige ydeevne
som den gennemsnitlige LDPE indkøbspose med bortskaffelse som skraldepose inden
forbrænding. Resultaterne refererer til det reference flow der er anført i Tabel I.
LDPE gennemsnitspose, genbrug som
skraldepose
Klimaforandring
Alle indikatorer
LDPE simpel, genbrug som skraldepose
0
1
LDPE fast håndtag, genbrug som skraldepose
0
0
LDPE genanvendt, genbrug som skraldepose
1
2
PP, ikke-vævet, genanvendelse
6
52
PP, vævet, genanvendelse
5
45
Genanvendt PET, genanvendelse
8
84
Polyester PET, genanvendelse
2
35
Biopolymer, genbrug som skraldepose og forbrænding
0
42
Ubleget papir, genbrug som skraldepose og forbræn-
0
43
ding
Bleget papir, genbrug som skraldepose og forbrænding
1
433
Økologisk bomuld, genbrug som skraldepose og for-
149
20000
brænding
Konventionelt bomuld, genbrug som skraldepose og
52
7100
forbrænding
Komposit, genbrug som skraldepose og forbrænding
23
870
LDPE-pose, fast håndtag: Kan genbruges direkte som skraldepose i forhold til alle
indikatorer. Genbrug som skraldepose, forbrænding.
LDPE-pose, genanvendt: Genbrug til indkøb mindst 1 gang i forhold til klimaforandringer,
mindst 2 gange når der tages højde for alle indikatorer. Genbrug som skraldepose,
forbrænding.
PP-pose, ikke-vævet: Genbrug til indkøb mindst 6 gange i forhold til klimaforandringer,
mindst 52 gange når der tages højde for alle indikatorer. Bortskaffes med genanvendelige
materialer, ellers genbrug som skraldepose hvis det er muligt, forbrænding.
PP-pose, vævet: Genbrug til indkøb mindst 5 gange i forhold til klimaforandringer, mindst
45 gange når der tages højde for alle indikatorer. Bortskaffes med genanvendelige
materialer, ellers genbrug som skraldepose hvis det er muligt, forbrænding.
PET-pose: Genbrug til indkøb mindst 8 gange i forhold til klimaforandringer, mindst 84
gange når der tages højde for alle indikatorer; bortskaffes med genanvendelige materialer,
genbrug som skraldepose hvis muligt, forbrænding.
Polyesterpose: Genbrug til indkøb mindst 2 gange i forhold til klimaforandringer, mindst 35
gange når der tages højde for alle indikatorer; bortskaffes med genanvendelige materialer,
ellers genbrug som skraldepose hvis muligt, forbrænding.
Biopolymerpose: Hvis muligt genbrug direkte som skraldepose i forhold til
klimaforandringer, skal genbruges mindst 42 gange til indkøb når der tages højde for alle
andre indikatorer. Genbrug som skraldepose hvis muligt, forbrænding.
Ubleget papirpose: Hvis muligt genbrug direkte som skraldepose i forhold til
klimaforandringer, skal genbruges mindst 43 gange når der tages højde for alle andre
indikatorer. Genbrug som skraldepose hvis muligt, forbrænding.
3 Den højeste værdi for bleget papir er sat til minimum at være den samme som ubleget papir.
10 The Danish Environmental Protection Agency / LCA of grocery carrier bags
Bleget papirpose: Genbrug til indkøb mindst 1 gang i forhold til klimaforandringer, mindst
43 gange når der tages højde for alle indikatorer. Genbrug som skraldepose hvis det er
muligt, ellers forbrænding.
Økologiske bomuldspose: Genbrug til indkøb mindst 149 gange for klimaændringer,
mindst 20000 gange når der tages højde for alle indikatorer. Genbrug som skraldepose hvis
det er muligt, ellers forbrænding.
Traditionelle bomuldspose: Genbrug til indkøb mindst 52 gange i forhold til
klimaforandringer, mindst 7100 gange når der tages højde for alle indikatorer. Genbrug som
skraldepose, hvis det er muligt, ellers forbrænding.
Kompositpose: Genbrug til indkøb mindst 23 gange i forhold til klimaforandringer, mindst
870 gange når der tages højde for alle indikatorer. Genbrug som skraldepose, hvis det er
muligt, ellers forbrænding.
Det understreges, at hvis reference LDPE-posen genbruges til indkøb, øges det nødvendige
antal gange de andre poser skal genbruges proportionalt. Resultaterne opnået for det
minimale antal genanvendelses gange er beregnet for at bidrage til en videre diskussion
mellem interessenterne om den forventede effektive levetid for hver indkøbspose i forhold til
det beregnede antal gange poserne skal genbruges. Selvom det beregnede antal genbrug kan
være i overensstemmelse med den funktionelle levetid for PP, PET og polyester
indkøbsposer, kan den overgå levetiden for bleget papir-, komposit- og bomuldsindkøbsposer,
især når man tager alle miljøindikatorer i betragtning.
Resumé af det kritiske review
Reviewere
En kritisk gennemgang i henhold til ISO 14040/14044 blev udført af Line Geest Jakobsen og
Trine Lund Neidel fra COWI A/S i Januar 2018
Review processen
Reviewet involverede følgende faser:
COWI udførte det første review i januar 2018
DTU svarede på de spørgsmål der blev stillet af COWI, og rettede rapporten i forhold de
kommentarer der var enighed om i reviewet fra januar 2018
COWI evaluerede de rettelser der var lavet, og sammenfattede den endelige review kom-
mentar.
Det kritiske review er vedhæftet i fulde i Appendix D. Hovedpunkterne fremhævet i det kritiske
review er angivet nedenfor.
LCA-rapporten er blevet gennemgået med hensyn til overholdelse af de internationale stan-
darder ISO 14040 og 14044. Rapporten viste sig i overordnet at overholde standarderne.
Forfatterne anfører, at rapporten ikke er i overensstemmelse med standarden, da et review
med inddragelse af et ekspertpanel ikke blev gennemført i projektfaserne.
Metoden valgt til fastsættelse af den funktionelle enhed og reference flow blev verificeret ved
en følsomhedsanalyse. Resultaterne af følsomhedsanalysen viste, at valget af reference flow
har stor indflydelse på bæreposer med høje miljøpåvirkninger forbundet med produktion og
poser med et lavere volumen end det, der udtrykkes i den funktionelle enhed (hovedsageligt
økologisk bomuld). Forfatterne tilføjede en dedikeret sektion om indkøbspose design, hvor de
giver kommentarer til den indflydelse som indkøbspose design har på resultaterne.
The Danish Environmental Protection Agency / LCA of grocery carrier bags
11
Det kritiske review understregede, at særlig opmærksomhed skal tillægges datakvalitetsvurde-
ring og at kritiske antagelser skal være tydeligt klargjort. Forfatterne tilføjede dedikerede afsnit
om datakvalitetsvurdering, kritiske antagelser samt hvilken indflydelse data og antagelser har
på resultaterne. Miljøpåvirkningen som udvalgte kritiske antagelser havde på resultaterne blev
vurderet med en følsomhedsanalyse.
Efter det første kritisk review, tilføjede forfatterne yderligere specifikationer på indkøbstyperne
(for eksempel polyester polymertypen), justerede sprog og grammatisk fejl og tilføjede yderli-
gere detaljer for at forbedre den overordnede forståelse af rapporten.
12 The Danish Environmental Protection Agency / LCA of grocery carrier bags
Executive summary - English
Conceptual framework
This study provides the life cycle environmental impacts of the production, use and disposal
(“cradle-to-grave”) of grocery carrier bags available for purchase in Danish supermarkets in
2017. The study was carried out by DTU Environment in the period October – December
2017.
Currently, Danish supermarkets provide multiple-use carrier bags of different materials (such
as recyclable and non-recyclable plastic, paper and cotton) designed for a multiple number of
uses. In order to compensate the environmental impacts arising from their manufacturing
phase, these multiple-use carrier bags need to be reused a number of times.
This study was commissioned by the Danish Environmental Protection Agency (Miljøstyrelsen)
with the aim to identify the grocery carrier bag with the best environmental performance to be
provided in Danish supermarkets. Moreover, the Miljøstyrelsen aimed at identifying a recom-
mended number of reuse times for each carrier bag based on their life cycle environmental
impacts. The project took into account that reuse of the carrier bag could occur both as prima-
ry reuse (where the carrier bag is reused for the same function for which it was produced, i.e.
for carrying grocery shopping from the supermarket to the home), or replacing other products
as waste bin liners (secondary reuse).
The following types of carrier bags were studied:
Low-density polyethylene (LDPE), 4 types: an LDPE carrier bag with average characteris-
tics, an LDPE carrier bag with soft handle, an LDPE carrier bag with rigid handle and a recy-
cled LDPE carrier bag;
Polypropylene (PP), 2 types: non-woven and woven;
Recycled polyethylene terephthalate (PET);
Polyester (of virgin PET polymers);
Starch-complexed biopolymer;
Paper, 2 types: unbleached and bleached;
Cotton, 2 types: organic and conventional;
Composite (jute, PP, cotton).
A survey conducted by DTU Environment showed that LDPE bags are always available for
purchase in all Danish supermarkets, while other carrier bag types are provided as alterna-
tives. Therefore, the average characteristics of the LDPE carrier bag were taken as reference.
The report considers only carrier bags available in Danish supermarkets in 2017 and it does
not include personal bags or other carriers. The report focuses on the environmental impacts
connected to the carrier bags, and does not consider the introduction of taxes, customers’
attitude or behavioural changes. The effects of littering were considered negligible for Den-
mark and not considered. The study was only done for material types already on the market,
and the functionality of these bags. This does not mean that other more optimal combinations
could not be relevant for future bag production (volume, recycled material, carrying capacity
etc.).
Methodological framework
The environmental assessment of the carrier bag alternatives was carried out with Life Cycle
Assessment (LCA), which is a standardized methodology that takes into account the potential
environmental impacts associated with resources necessary to produce, use and dispose the
The Danish Environmental Protection Agency / LCA of grocery carrier bags
13
product, and also the potential emissions that may occur during its disposal. When material
and energy resources are recovered, the system is credited with the avoided potential emis-
sions that would have been necessary in order to produce these resources. In order to com-
pare the carrier bags, we took into account how many of the different types were necessary in
order to fulfil the function provided by an LDPE carrier bag with average characteristics, which
was:
“Carrying one time grocery shopping with an average volume of 22 litres and with an
average weight of 12 kilograms from Danish supermarkets to homes in 2017 with a
(newly purchased) carrier bag. The carrier bag is produced in Europe and distributed to
Danish supermarkets. After use, the carrier bag is collected by the Danish waste man-
agement system”.
As shown in Table I, two bags were necessary to fulfil the function in the case of simple LDPE,
recycled LDPE, biopolymer, paper, and organic cotton bags. For these bags, either the volume
or weight holding capacity required was not fulfilled. Organic and conventional cotton bags
were modelled separately in order to differentiate the results for the different types of material,
since organic cotton production has a lower yield than conventional cotton (Forster et al.,
2013). Table I shows that organic cotton required two carrier bags, since the volume of the
organic cotton bag did not fulfil the volume requirements expressed in the functional unit.
Table I. Carrier bag alternatives considered for this LCA study and number of bags
required to fulfil the functionality provided by an LDPE carrier bag with average charac-
teristics.
Reference flow
Material carrier bag
Type carrier bag
(number of bags needed)
Plastic
LDPE (average)
1 (reference bag)
Plastic
LDPE simple
2
Plastic
LDPE rigid handle
1
Plastic
LDPE recycled
2
Plastic
PP non-woven
1
Plastic
PP woven
1
Plastic
PET recycled
1
Plastic
Polyester
1
Bioplastic
Biopolymer
2
Paper
Paper, unbleached
2
Paper
Paper, bleached
2
Textile
Cotton organic
2
Textile
Cotton conventional
1
Composite
Jute, PP, cotton
1
The environmental assessment of each carrier bag was carried out taking into consideration
different end-of-life options: incineration (EOL1), recycling (EOL2), and reuse as waste bin bag
(EOL3) before being incinerated. For all carrier bag alternatives, the assessment took into
account impacts arising from production of the carrier and its packaging (assumed to occur in
Europe), transportation to Denmark, use, and disposal (which could occur in Denmark or with-
in Europe). The general structure of the processes taken into account is shown in Figure I.
The environmental assessment was carried out for a range of recommended environmental
impacts (European Commission, 2010): climate change, ozone depletion, human toxicity can-
cer and non-cancer effects, photochemical ozone formation, ionizing radiation, particulate
matter, terrestrial acidification, terrestrial eutrophication, marine eutrophication, freshwater
14 The Danish Environmental Protection Agency / LCA of grocery carrier bags
eutrophication, ecosystem toxicity, resource depletion, fossil and abiotic, and depletion of
water resource.
The number of primary reuse times for each carrier bag, end-of-life scenario and impact cate-
gory was calculated assuming that a reuse X times of a carrier bag allowed avoiding the cor-
responding use X times of the reference LDPE carrier bag with average characteristics, or
more simply, for every time a bag is reused it avoids the full life cycle of the reference bag. A
representation of primary reuse is provided in Figure II. Considering the cradle-to-grave LCA
result for and alternative carrier bag A as
LCIAA and the cradle-to-grave LCA result for the
average LDPE carrier bag as
LCIALDPE, the number of reuse times
x was calculated as follows:
LCIA
LCIA
A
LDPE
x
LCIALDPE
The LCA study was based on publicly available LCI data and data from existing LCA studies
on grocery carrier bags. The study presented some data limitations and assumptions, for ex-
ample regarding the choice of reference flow, the modelling of material production and carrier
bag manufacture. A sensitivity analysis was performed on critical assumptions and choices
made.
Production of
End-of-life
packaging
Col ection
Transport
packaging
material
Production of
Manufacture
carrier bag
Transport
Use
of carrier bag
material
End-of-life
Treatment
carrier bag
Col ection
residues
(EOL1/EOL2/
EOL3)
Figure I. General structure for all carrier bag scenarios assessed in this LCA study.
“EOL” refers to three different end-of-life options. EOL1: incineration, EO2: recycling,
EOL3: reuse as waste bin bag.
Reuse X
Production of
Carrier bag
times
carrier bag
A
EOL
(Primary
A
(Primary use)
reuse)
Avoidance
X times
Production of
Carrier bag
carrier bag
LDPE
EOL
LDPE
(Primary use)
Figure II. Generic modelling of primary reuse. The example portrays the primary reuse X
times of a generic “carrier bag A”. The reuse X times allows avoiding X times the pro-
duction, use and disposal of the reference LDPE carrier bag.
The Danish Environmental Protection Agency / LCA of grocery carrier bags
15
Findings and recommendations
The LCA study provided a number of findings that can be useful for optimizing the use and
disposal of the carrier bags available for purchase in Denmark. The results are referred to the
reference flows presented in Table I.
Which is the most preferable disposal option for each type of carrier bag?
After reusing the carrier bag as many times as possible, reusing the carrier bag as a waste bin
bag is better than simply throwing away the bag in the residual waste and it is better than
recycling. Recycling can potentially offer benefits in the case of heavy plastic bags, such as
PP, PET and polyester. Reuse as a waste bin bag is most beneficial for light carrier bags,
such as LDPE, paper and biopolymer. When reuse as a waste bin bag is not feasible, for ex-
ample when the bag can easily be punctured, torn, or wetted, as in the case of paper and
biopolymer bags, incineration is the most preferable solution from an environmental point of
view. Table II provides a summary of the results obtained for each carrier bag.
Table II. Overview of the most preferable end-of-life option for each of the carrier bag
types assessed.
Carrier bag material
Preferable end-of-life after normal reuse
Plastic, LDPE
Reuse as waste bin bag
Plastic, PP
Recycle, reuse as waste bin bag if possible, else incinerate
Plastic, recycled PET
Recycle, reuse as waste bin bag if possible, else incinerate
Plastic, polyester PET
Reuse as waste bin bag if possible, else incinerate
Biopolymer
Reuse as waste bin bag if possible, else incinerate
Paper
Reuse as waste bin bag if possible, else incinerate
Textile
Reuse as waste bin bag if possible, else incinerate
Composite
Reuse as waste bin bag if possible, else incinerate
Which is the carrier bag providing the lowest environmental impacts?
In general with regards to production and disposal, LDPE carrier bags, which are the bags that
are always available for purchase in Danish supermarkets, are the carriers providing the over-
all lowest environmental impacts for most environmental indicators (Table III). In particular,
LDPE carrier bags with rigid handle provided in general the lowest environmental impacts in
the majority of the impact categories included in this LCA study. Carrier bags alternatives that
can provide a similar performance are unbleached paper and biopolymer bags, but for a lower
number of environmental indicators. Heavier carrier bags, such as PP, PET, polyester,
bleached paper and textile bags need to be reused multiple times in order to lower their envi-
ronmental production cost. Between the same bag types, woven PP carrier bags provided
lower impacts than non-woven PP bags, unbleached paper resulted more preferable than
bleached paper, and conventional cotton over organic cotton.
How many times should the carrier bags be reused?
For all carrier bags, reuse as many times as possible before disposal is strongly encouraged.
Table IV reports the number of calculated primary reuse times necessary to lower the envi-
ronmental impacts associated with all carrier bag alternatives to the levels of the LDPE carrier
bag. Therefore, the numbers reported in Table IV refer to minimum number of reuse times.
The number of calculated reuse times varies if only one environmental indicator is observed,
or if all environmental indicators are taken into account. The calculated number of reuse times
might be compliant with the lifetime of PP, PET and polyester carrier bags, but might surpass
the lifetime of bleached paper, composite and cotton carriers, especially considering all envi-
ronmental indicators. The number of calculated reuse times was rather uniform across impact
categories for LDPE carrier bags. For PP, PET, biopolymer and paper carrier bags, some
16 The Danish Environmental Protection Agency / LCA of grocery carrier bags
impact categories presented higher reuse times than others. Lastly, the very high number of
reuse times scored by cotton and composite bags is primarily due only to the ozone depletion
impact category, for which the cotton production dataset provides larger impacts than the
reference LDPE carrier bag.
Table III. Carrier bags providing the lowest environmental impacts for all the environ-
mental indicators considered. The order in which the bags are listed corresponds to the
raking of their LCA results starting from the lowest impact. Only the three lowest scor-
ing bags are listed. The results refer to the reference flow provided in Table I.
Environmental indicator
Carrier bags providing lowest impacts
Climate change
Paper unbleached, biopolymer, LDPE
Ozone depletion
LDPE
Human toxicity, cancer effects
Paper unbleached, LDPE
Human toxicity, non-cancer effects
Composite, PP, LDPE
Photochemical ozone formation
LDPE
Ionizing radiation
LDPE
Particulate matter
LDPE
Terrestrial acidification
LDPE
Terrestrial eutrophication
LDPE
Freshwater eutrophication
LDPE
Marine eutrophication
PP, LDPE
Ecosystem toxicity
LDPE
Resource depletion, fossil
Paper unbleached, LDPE
Resource depletion, abiotic
PP, LDPE
Water resource depletion
LDPE, biopolymer
Table IV. Calculated number of primary reuse times for the carrier bags in the rows, for
their most preferable disposal option, necessary to provide the same environmental
performance of the average LDPE carrier bag, reused as a waste bin bag before incin-
eration. The results refer to the reference flow provided in Table I.
LDPE average, reused as waste bin bag
Climate Change
All indicators
LDPE simple, reused as waste bag
0
1
LDPE rigid handle, reused as waste bag
0
0
Recycled LDPE, reused as waste bag
1
2
PP, non-woven, recycled
6
52
PP, woven, recycled
5
45
Recycled PET, recycled
8
84
Polyester PET, recycled
2
35
Biopolymer, reused as waste bag or incinerated
0
42
Unbleached paper, reused as waste bag or incinerated
0
43
Bleached paper, reused as waste bag or incinerated
1
434
Organic cotton, reused as waste bag or incinerated
149
20000
4 The highest value for bleached paper is set to as minimum be equal to the value for unbleached paper.
The Danish Environmental Protection Agency / LCA of grocery carrier bags
17
Conventional cotton, reused as waste bag or incinerated
52
7100
Composite, reused as waste bag or incinerated
23
870
The sensitivity analysis on data and assumptions highlighted the importance of the choice of
reference flow, which was determining for the calculated number of reuse times for organic
cotton. The reference flow choice depends on the fulfilment of the function expressed by the
functional unit. In particular, the results showed the importance of the carrier bags design,
which should be focused on maximizing volume and weight holding capacity, while minimizing
the amount of material needed and the final weight of the carrier bag.
Our final recommendations are the following5:
Simple LDPE bags: Can be directly reused as waste bin bags for climate change, should
be reused at least 1 time for grocery shopping considering all other indicators; finally reuse
as waste bin bag.
LDPE bags with rigid handle: Can be directly reused as waste bin bags considering all
indicators; finally reuse as waste bin bag.
Recycled LDPE bags: Reuse for grocery shopping at least 1 time for climate change, at
least 2 times considering all indicators; finally reuse as waste bin bag.
PP bags, non-woven: Reuse for grocery shopping at least 6 times for climate change, at
least 52 times considering all indicators; finally dispose with recyclables, otherwise reuse as
waste bin bag if possible, lastly incinerate.
PP bags, woven: Reuse for grocery shopping at least 5 times for climate change, at least
45 times considering all indicators; finally dispose with recyclables, otherwise reuse as
waste bin bag if possible, lastly incinerate.
PET bags: Reuse for grocery shopping at least 8 times for climate change, at least 84 times
considering all indicators; finally dispose with recyclables, otherwise reuse as waste bin bag
if possible, lastly incinerate.
Polyester bags: Reuse for grocery shopping at least 2 times for climate change, at least 35
times considering all indicators; finally dispose with recyclables, otherwise reuse as waste
bin bag if possible, lastly incinerate.
Biopolymer bags: Can be directly reused as waste bin bags for climate change, should be
reused at least 42 times for grocery shopping considering all other indicators. Finally, reuse
as waste bin bag if possible, otherwise incinerate.
Unbleached paper bags: Can be directly reused as waste bin bags for climate change,
should be reused at least 43 times considering all other indicators. Finally, reuse as waste
bin bag if possible, otherwise incinerate.
Bleached paper bags: Reuse for grocery shopping at least 1 time for climate change, at
least 43 times considering all indicators; reuse as waste bin bag if possible, otherwise incin-
erate.
Organic cotton bags: Reuse for grocery shopping at least 149 times for climate change, at
least 20000 times considering all indicators; reuse as waste bin bag if possible, otherwise
incinerate.
Conventional cotton bags: Reuse for grocery shopping at least 52 times for climate
change, at least 7100 times considering all indicators; reuse as waste bin bag if possible,
otherwise incinerate.
5 The number of times for “all indicators” refers to the highest number of reuse times among those calcu-
lated for each impact category. For light carrier bags (LDPE, PP, PET...) the high numbers of reuse times
are given by a group of impact categories with similar high values. Conversely, for composite and cotton
the very high number of reuse times is given by the ozone depletion impact alone. Without considering
ozone depletion, the number of reuse times ranges from 50 to1400 for conventional cotton, from 150 to
3800 for organic cotton, and from 0 to 740 for the composite material bag. The highest number is due to
the use of water resource, but also to freshwater and terrestrial eutrophication. Results for the number of
reuse times for each impact category, minimum-maximum ranges and average number of reuse times
are provided in Appendix C.
18 The Danish Environmental Protection Agency / LCA of grocery carrier bags
Composite bags: Reuse for grocery shopping at least 23 times for climate change, at least
870 times considering all indicators; reuse as waste bin bag if possible, otherwise incinerate.
It should be considered that if the reference LDPE bag is reused for shopping, this will in-
crease the needed number of reuse times for the other bags proportionally. The results ob-
tained on the minimum number of reuse times are intended to raise the discussion among the
stakeholders on the effective expected lifetime of each carrier bag. While the calculated num-
ber of reuse times might be compliant with the functional lifetime of PP, PET and polyester
carrier bags, it might surpass the lifetime of bleached paper, composite and cotton carriers,
especially considering all environmental indicators.
Summary of the critical review
Reviewers
A critical review according to ISO 14040/14044 was performed by Line Geest Jakobsen and
Trine Lund Neidel from COWI A/S in January 2018.
Review process
The review process involved the following phases:
COWI conducted the first review in January 2018.
DTU answered to the questions raised by COWI and corrected the report according to the
outcomes of the review in January 2018.
COWI evaluated the corrections and compiled a final review statement.
The critical review from COWI can be found in full in Appendix D. The main points highlighted
in the critical review are provided below.
The LCA report has been reviewed with respect to compliance with the ISO 14040 and 14044
International Standards. The report was found to comply with the standards to a large extent.
The authors state that the report does not comply with the standard because an exchange with
a panel of experts was not made during the project phases.
The method chosen for selecting the functional unit and reference flow was verified with a
sensitivity analysis. The results of the sensitivity analysis showed that the choice of reference
flow influenced heavily the carrier bags with high impacts connected to production and with a
lower volume than the one expressed in the functional unit (mainly organic cotton). The au-
thors added a dedicated section on carrier bag design where they provide comments on the
influence of the carrier bag design on the results.
The critical review highlighted that specific attention should have been dedicated to data quali-
ty assessment and to the clear statement of critical assumptions. The authors added dedicat-
ed sections on data quality assessment, critical assumption and on the influence on data and
assumptions on the results. The influence of selected critical assumptions on the results was
assessed with a sensitivity analysis.
After the review, the authors added further specifications on the carrier bag types (e.g. polyes-
ter polymer type), adjusted language and typos, and added further details for improving the
overall understanding of the report.
The Danish Environmental Protection Agency / LCA of grocery carrier bags
19
Preface
This study provides the life cycle environmental impacts associated with the production, use
and disposal of selected grocery carrier bags available in Danish supermarkets in 2017.
The commissioner of the LCA is the Danish Environmental Protection Agency (Miljøstyrelsen).
The LCA was conducted by DTU Environment in the period October – December 2017, using
the EASETECH LCA model developed by DTU Environment for the environmental assess-
ment of waste management systems and environmental technologies. The LCA was conduct-
ed for assessing and comparing the environmental impacts associated with the grocery carrier
bags currently available in Danish supermarkets.
The LCA has been conducted according to the requirements outlined in DS/EN ISO Interna-
tional Standards 14040 and 14044; however, the report is not intended to strictly comply with
the standard. The report is intended for internal decision support at the Danish Environmental
Protection Agency as part of a wider range of assessments aiming at investigating possible
options for grocery carrier bags available in Danish supermarkets. The report has undergone a
peer review process outside the project group in January 2018 by Line Geest Jakobsen and
Trine Lund Neidel from COWI A/S.
The report was prepared by Valentina Bisinella, Paola Federica Albizzati, Thomas Fruergaard
Astrup, and Anders Damgaard from DTU Environment.
DTU, February 2018
20 The Danish Environmental Protection Agency / LCA of grocery carrier bags
List of Abbreviations
General
EOL
End-of-life (as: “treatment”, “waste management” or “disposal”)
EOL1
Incineration
EOL2
Source segregation of recyclables and recycling
EOL3
Reuse as a waste bin bag before incineration
HDPE
High-density polyethylene
LCA
Life cycle assessment
LCI
Life cycle inventory
LCIA
Life cycle impact assessment
LDPE
Low-density polyethylene
PE
Persons equivalents (normalized LCA results)
PET
Polyethylene terephthalate
PP
Polypropylene
W
Waste bin bag
Carrier bag scenarios
LDPEavg
LDPE carrier bag, average characteristics (between LDPEs and LDPEh)
LDPEs
LDPE carrier bag, simple
LDPEh
LDPE carrier bag, rigid handle
LDPErec
Recycled LDPE carrier bag
PP
Non-woven PP carrier bag
PPwov
Woven PP carrier bag
PETrec
Recycled PET carrier bag
PETpol
Polyester carrier bag
BP
Starch-complexed biopolymer carrier bag
PAP
Unbleached craft paper carrier bag
PAPb
Bleached craft paper carrier bag
COTorg
Organic cotton carrier bag
COT
Conventional cotton carrier bag
COM
Composite carrier bag (jute, PP, cotton)
Acronyms for the impact categories assessed by the LCA
CC
Climate change
OD
Ozone depletion
HTc
Human toxicity, cancer effects
HTnc
Human toxicity, non-cancer effects
POF
Photochemical ozone formation
IR
Ionizing radiation
PM
Particulate matter
TA
Terrestrial acidification
TE
Terrestrial eutrophication
ME
Marine eutrophication
FE
Freshwater eutrophication
ET
Ecosystem toxicity
RDfos
Resource depletion, fossil
RD
Resource depletion, abiotic
Water
Water resource depletion
The Danish Environmental Protection Agency / LCA of grocery carrier bags
21
Key definitions
Primary reuse
Reuse for the same function for which the product was produced.
For example, the function of grocery carrier bags is to contain and transport
groceries and goods from the supermarkets to the homes. Primary reuse of a
carrier bag would be reusing it for carrying goods and groceries from the
supermarkets to the homes.
Secondary reuse
Reuse fulfilling a different function than the one for which the product was
produced.
For example, grocery carrier bags are produced to contain and transport
groceries and goods from the supermarkets to the homes. Secondary reuse
of a carrier bag could be used as a waste bin bag, bag for laundry, etc. Any
reuse that does not entail carrying goods and groceries from the supermar-
kets to the homes.
Single-use carrier bag
Lightweight carrier bags intended to be used for one shopping trip from the
supermarkets to the homes.
Multiple-use carrier bag Durable carrier bags intended to be used for multiple shopping trips from the
supermarkets to the homes.
Grocery carrier bag
Bag product, usually light, resistant and capacious, with the primary function
of containing and transporting goods and groceries from the supermarkets to
the homes.
Lightweight plastic
Single-use plastic carriers, commonly made of low-density or high-density
carrier bags
polyethylene plastic (LDPE or HDPE) with thickness below 50 microns (Euro-
pean Commission, 1994).
Very lightweight plastic Small plastic carrier bags with thickness below 15 microns (European Com-
carrier bags
mission, 1994), which are available supermarkets free of charge as primary
packaging for loose food.
22 The Danish Environmental Protection Agency / LCA of grocery carrier bags
1. Introduction and objectives
This study was commissioned by the Danish Environmental Protection Agency (Miljøstyrelsen)
in order to assess the life cycle environmental impacts of the production, use and disposal of
different grocery carrier bags available for purchase in supermarkets in Denmark in 2017. This
Section provides the background on grocery carrier bags in Denmark and the aim of the study.
1.1
Background
Carrier bags are used in supermarkets in order to carry grocery shopping and other items sold
at supermarkets from the shops to the homes. Grocery carrier bags are considered a form of
packaging and have been addressed in the European Parliament and Council Directive
94/62/EC on packaging and packaging waste (European Commission, 1994). The Directive,
which is currently in force, aims at limiting the production of packaging waste and promoting
recycling, reuse and other forms of waste recovery. Lightweight plastic carrier bags are single-
use plastic carriers6, commonly made of low-density or high-density polyethylene plastic
(LDPE or HDPE). These carriers are single-use in the sense that they are usually only used
for one shopping trip (European Commission, 2011). The environmental concerns associated
with plastic carrier bags include the use of non-renewable resources for production (such as
crude oil), the environmental impacts of their disposal and the effects of littering. In particular,
the Directive aimed at reducing the large consumption of single-use carrier bags in order to
ultimately reduce the amounts to be disposed.
Since 1993, Denmark has taken action against single-use plastic carrier bags by introducing a
tax on retailers. Currently, Danish supermarkets provide multiple-use carrier bags of different
materials (such as recyclable and non-recyclable plastic, paper and cotton) which can be
bought by customers at the cash register. These types of multiple-use carrier bags are de-
signed for a multiple number of uses and are intended to last longer, therefore requiring more
resources in their production and potentially more environmental impacts than a single-use
carrier bag. In order to compensate the impacts arising from their manufacturing phase, multi-
ple-use carrier bags need to be reused a number of times. However, due to the functionality
issue or customer attitude, if the reusable bags are thrown away before their desired number
of use, the environmental impacts may surpass those of single-use bags. Moreover, reuse of
the carrier bag can occur both as primary reuse (where the carrier bag is reused for the same
function for which it was produced, i.e. for carrying grocery shopping from the supermarket to
the home), or replacing other products as waste bin liners (secondary reuse).
1.2
Aim of the study
The aim of this study is to identify the multiple-use carrier bag alternative with the best envi-
ronmental performance to be provided in Danish supermarkets. In order to do so, the study
aims to assess the environmental impacts associated with production, distribution, use and
disposal of the multiple-use carrier bags available for purchase in Danish supermarkets in
2017, for a range of environmental impacts. Three end-of-life options were taken into account
for the disposal. In particular, the study wishes to:
Identify the best disposal option for each carrier bag type within the identified end-of-life
options;
6 “Lightweight plastic carrier bags” shall mean plastic carrier bags with thickness below 50 microns
(European Commission, 1994).
The Danish Environmental Protection Agency / LCA of grocery carrier bags
23
Identify the multiple-use carrier bag alternative with the best environmental performance for
each of the investigated impact categories;
Define the number of times a multiple-use carrier bag would need to be reused in order to
provide a better environmental performance than another carrier bag alternative, for a range
of environmental indicators.
The study aims to obtain the number of reuse times taking into consideration primary and
secondary reuse, as well as separate collection and recycling of the material, between the
disposal options.
The environmental assessment of the carrier bag alternatives is carried out with Life Cycle
Assessment (LCA), a standardized methodology for quantifying environmental impacts of
providing, using and disposing of a product or providing a service throughout its life cycle (ISO,
2006). LCA takes into account the potential environmental impacts associated with resources
necessary to produce, use and dispose the product, and also the potential emissions that may
occur during its disposal. When material and energy resources are recovered, the system is
credited with the avoided potential emissions that would have been necessary in order to pro-
duce these resources. The LCA will be carried out with the EASETECH model developed at
DTU Environment (Clavreul et al., 2014). The goal definition of the LCA and the LCA method-
ology are provided in a dedicated Section.
The LCA modelling includes the actual multiple-use carrier bag options currently available for
purchase in Danish supermarkets, which were identified by a dedicated survey. In particular,
the modelling takes into account the material of the carrier bag, for example including whether
the material is virgin or recycled, recyclable or non-recyclable. The study will assess whether a
large variation exists within carrier-bag types, in terms of weight, volume, thickness, and carry-
ing capacity.
The present study only considers carrier bags available for purchase in Danish supermarkets
in 2017. Small very lightweight plastic carrier bags7, which are available in Danish supermar-
kets free of charge as primary packaging for loose food, were excluded from the scope of this
study, since they were not included in the 94/62/EC measures. This study does not include the
assessment of other types of carriers, such as personal bags or bags provided by other retail-
ers. The report does not consider behavioural changes or consequences of introducing further
economic measures. The study does not take into account economic consequences for retail-
ers and carrier bag producers. The environmental assessment does not take into account the
effects of littering.
7 “Very lightweight plastic carrier bags” shall mean plastic carrier bags with thickness below 15 microns
(European Commission, 1994).
24 The Danish Environmental Protection Agency / LCA of grocery carrier bags
2. Carrier bags
2.1
Carrier bag types
Carrier bags are provided in supermarkets with the function to carry goods and groceries from
the supermarkets to the homes. Carrier bags must therefore be robust and large enough to
hold a certain amount of items, while at the same time being economically convenient. Carrier
bags can be made of plastic materials of fossil origin, such as low- or high-density polyeth-
ylene (LDPE/HDPE), polypropylene (PP), polyethylene terephthalate (PET) and polyester.
Alternative plastic materials composed of carbon of biogenic origin can also be used, such as
polyester-complexed starch biopolymer. Other materials used for carrier bags are paper and
textiles. A few types of carrier bags are described below. All the bags analysed in this report
are intended to be used multiple times.
Low-density polyethylene (LDPE) bags
Plastic bags formed from an LDPE plastic melt, which is blown and sealed to form a bag.
Figure 1 provides two examples of LDPE carrier bag: one with simple handle, one with a rig-
id handle.
a)
b)
Figure 1. Examples of LDPE carrier bags with (a) simple handle (Paxonplastic, 2018)
and (b) rigid handle (C-bags, 2018).
Non-woven polypropylene (PP) bags
Plastic bags formed from molten filament of PP, which is spun bonded. Non-woven PP bags
are stronger, more durable and generally larger in volume than LDPE carrier bags and are
intended to be reused many times (Edwards and Fry, 2011). Figure 2 provides an example
of non-woven PP bags and of the fabric type.
a)
b)
Figure 2. Examples of non-woven PP bags (a) (Indiamart, 2018) and (b) detail of the non-
woven PP fabric (Bharatcottons, 2018).
The Danish Environmental Protection Agency / LCA of grocery carrier bags
25
Woven polypropylene (PP) bags
Plastic bags obtained from weaving PP fibres. Just like non-woven PP bags, these bags are
usually stronger and more durable than LDPE carrier bags. Figure 3 provides an example of
woven PP bags and fabric.
a)
b)
Figure 3. Example of a woven PP bag (a) (Indiamart, 2018b) and (b) detail of the woven
PP fabric (Bagsupplies, 2018).
Recycled polyethylene terephthalate (PET) bags
Plastic bags obtained from weaving molten fibres from recycled PET pellets. Strong and du-
rable, intended for multiple-use. An example is provided in Figure 4.
Figure 4. Example of recycled PET bag (Customgrocerybags, 2018).
Polyester bags
Plastic bags obtained from weaving polyester fibres. These polyester fibres are obtained
from processing other polymer types, such as PP or PET, and are usually thinner and lighter
than the original polymers, resulting in a very light and foldable multiple-reuse bag. An ex-
ample is provided in Figure 5.
Figure 5. Example of a polyester carrier bag (Aliexpress, 2018).
26 The Danish Environmental Protection Agency / LCA of grocery carrier bags
Biopolymer bags
Biopolymer bags are usually composed by either polylactic acid (PLA) or starch polyester
blends, which are compostable materials able to decompose in in aerobic environments that
are maintained under specific controlled temperature and humidity conditions (ASTM, 2018).
An example is provided in Figure 6. These carrier bags are usually less resistant than LDPE
bags. The biodegradability of these polymers is debated in the scientific community. Most of
the materials are only biodegradable in full scale facilities (compost or anaerobic) run at high
enough temperatures, and there can still be partial plastic parts left at the end of treatment,
In most natural environments only a small part of the plastic will degrade (Emadian et al.,
2017)
Figure 6. Example of biopolymer bags (Ecostoviglie, 2018).
Paper bags
Carrier bags obtained from craft paper, which is glued to form the bag. This type of carrier
bag has become less used since the 1970s, replaced by plastic bags that do not tear when
wet (Edwards and Fry, 2011). An example is provided in Figure 7.
Figure 7. Example of a paper bag (Natuerlich-verpacken, 2018).
Textile bags
Bags made of woven cotton or jute, intended to be reused many times. Textile bags can be
made of organic or conventional textiles. Figure 8 provides an example of a cotton bag.
Figure 8. Example of cotton carrier bag (Amazon, 2018).
The Danish Environmental Protection Agency / LCA of grocery carrier bags
27
Composite bags
Bags made of multiple material types, such as textile and plastic. An example is provided in
Figure 9 below, where plastic handles are attached to a jute bag.
Figure 9. Example of composite bag (Topcottonbags, 2018).
2.2
Carrier bags available in Denmark
Since this study focuses on the multiple-use carrier bag alternatives available for purchase in
Danish supermarkets in 2017, we have conducted a survey in order to identify the carrier bag
alternatives on which to carry out the environmental assessment. The survey was conducted
in September – October 2017 as part of a Master thesis project work at DTU Environment
(Alonso Altonaga, 2017).
The survey involved collecting all types of carrier bags available in Danish supermarkets. The
survey involved a total of 19 retailers: Fakta, Fakta Q, Superbrugsen, Dagli' Brugsen, Irma,
Kvickly, Netto, Føtex food, Føtex, Bilka, 7-eleven, Rema 1000, Lidl, Aldi, Meny, Spar, Min
købmand, Let-Køb, and Løvbjerg. The material of each carrier bag was identified based on the
labelling on the carrier bag and it was verified with material analysis via infrared spectroscopy.
The number of number of carrier bags surveyed per material type was reported. Then, we
analysed the weight, volume, thickness and weight holding capacity (measured as tensile
strength at the point where the material started to stretch or broke) for each of the carrier bags.
Table 1 shows the material and the material type of the carrier bags available for purchase in
Danish supermarkets in 2017, with detail on the retailers providing each type of bag. For each
type of carrier bag, Table 2 provides the number of items identified by the survey, the average
weight of the bag, the average volume, the average thickness and average weight holding
capacity.
The total number of carrier bag types available in Danish supermarkets which was identified in
the project was 40. The virgin LDPE plastic bag was identified as the most commonly available
bag in Danish supermarkets with 23 items. In particular, the survey indicated that an LDPE
carrier bag can always be found for purchase in all supermarkets, regardless of the retail chain
they belong to. Two retailers provided also LDPE bags made of recycled LDPE, on top of
virgin LDPE plastic bags. Both virgin and recycled LDPE grocery carrier bags were found in
two versions: one with a rigid handle (of the same material; “LDPE rigid handle” in Table 2)
and a simple type, with a handle of the same thickness of the bag (“LDPE simple” in Table 2).
The same retailer often provided both types of LDPE carrier bags. All remaining types of carri-
er bags were considerably less abundant, scoring a total of 1 to 3 items. This reflects the fact
that some retailers provided other types of carrier bags as an alternative to the most common
LDPE carrier bag. The material types of such carrier bag types were woven and non-woven
PP, recycled PET, polyester of virgin PET fibres, biodegradable plastic, craft paper, cotton
(organic and conventional). One bag type presented composite characteristics, with jute, PP
and cotton materials combined. Often the alternatives to LDPE were heavier, multiple-use-
oriented carrier bags, as in the case on woven and non-woven PP, recycled PET and cotton
28 The Danish Environmental Protection Agency / LCA of grocery carrier bags
bags. Nine supermarkets provided at least one alternative to the LDPE carrier bag. Irma was
the supermarket with the largest number of alternative options for the choice of carrier bag.
Table 1. Material and material type of the multiple-use carrier bags available for pur-
chase in Danish supermarkets in 2017, subdivided by retailer. (*) indicates that the
LDPE carrier bags are available both as virgin plastic and recycled plastic.
n
n
nd
se
se
od
n
00
a
a
Q
x
b
a
ug
ug
o
l
jerg
Material
Type
x fo
te
bm
Kø-
Fakt
Irma
Bilka
eleve
Lid
Aldi
Spar
vb
Fakt
Kvickly
Nett
te
Fø
-
Meny
Let
Fø
7
Rema 10
Lø
Superbr
Dagli Br
Min kø
Plastic
LDPE simple
X X X X
X X X X X* X*
X X
Plastic
LDPE rigid handle
X X X
X X X X X
X X*
X X X
X
Plastic
PP non-woven
X
X
X
Plastic
PP woven
X
X
X
Plastic
PET recycled
X
Plastic
Polyester, PET
X
Bioplastic Biopolymer
X
Paper
Paper
X
Textile
Cotton organic
X
Textile
Cotton conventional
X X
Composite Jute, PP, cotton
X
The carrier bags identified in the survey varied in terms of weight, volume, thickness and
weight holding capacity, as presented in Table 2. We could identify a direct correlation be-
tween thickness and weight of the bag. The larger the thickness, the more material was em-
ployed and the heavier the carrier bag. Table 2 indicates that LDPE and biopolymer plastic
bags presented the lowest average thickness and weight. When the LDPE carrier bag was
equipped with a rigid handle, the overall average weight of the carrier bag was larger (high-
lighted in grey and italics in Table 2). Paper carrier bags presented the second-lowest average
thickness and weight. On the other hand, woven and non-woven PP, recycled PET, PET poly-
ester, cotton and composite carrier bags presented considerably larger weight. The average
weight holding capacity generally follows the same trend of weight of the bag and thickness,
with thicker bags generally providing a larger holding capacity, with exception of paper bags.
On the other hand, the volume of the bag was not related to weight or thickness. Simple LDPE
bags presented the lowest volume, followed by biopolymer, organic cotton and LDPE bags
with rigid handle. The largest volumes were recorded for woven PP and recycled PET bags
After the first draft of the report was provided to Miljøstyrelsen and stakeholders, the stake-
holders in the project group highlighted that another conventional cotton bag was available for
purchase from one of the retailers. This cotton bag presents a larger volume (31 litres) and
lower weight (120 grams), which would change the average weight of the cotton bag present-
ed in Table 2 to 195 grams and a volume of 28 litres. The latter average characteristics were
not included in the modelling, but were used in the discussion of the results.
Overall, the survey allowed identifying important aspects that need to be taken into account
when carrying out the LCA of carrier bag alternatives:
LDPE carrier bags are the most common type of carrier bag and the carrier bag type that
can always be found in Danish supermarkets. Therefore, the LCA study should take this car-
The Danish Environmental Protection Agency / LCA of grocery carrier bags
29
rier bag as baseline and compare how many times the other carrier bags should be reused
in order to reach a similar environmental performance.
The carrier bags have considerable differences in weight, and bags with larger weight are
likely to have larger environmental impacts due to the larger amount of material required to
manufacture the grocery carrier bag.
The bags have different characteristics and cannot all cover the same functionality. The
functional unit has to be tailored in a way that a fair comparison is provided.
Table 2. Survey results of the grocery carrier bags.
Average Average Average
Average weight
Number
Material
Type
weight volume thickness holding capacity
of items
(g)
(L)
(mm)
(kg)
Plastic
LDPE
23
24.2
22.4
0.04
12.0
Plastic
LDPE simple
10
17.9
19.2
0.04
10.5
Plastic
LDPE rigid handle
13
29.0
24.8
0.05
13.2
Plastic
LDPE recycled
3
24.9
21.7
0.05
10.7
Plastic
LDPE recycled, simple
1
14.7
15.0
0.04
8.0
Plastic
LDPE recycled, rigid handle
2
30.0
25.0
0.05
12.0
Plastic
PP non-woven
2
137.0
29.0
0.50
36.0
Plastic
PP woven
3
118.7
36.7
0.35
41.0
Plastic
PET recycled
2
159.0
42.0
0.60
45.0
Plastic
PET polyester
1
48.0
32.0
0.10
45.0
Bioplastic Biopolymer
1
18.2
22.0
0.04
12.0*
Paper
Paper
1
44.7
23.0
0.12
12.0*
Textile
Cotton organic
1
252.0
20.0
1.40
50.0
Textile
Cotton conventional
2
232.0
27.0
0.93
50.0
Composite Jute, PP, cotton
1
282.0
32.0
0.70
50.0
* The average weight holding capacity was 12 kg, but the samples of these types of carrier bags present-
ed the highest variation of weight holding capacity. For example, the bags were easily torn if containing
items with sharp edges.
30 The Danish Environmental Protection Agency / LCA of grocery carrier bags
3. LCA Methodology
The LCA carried out for this study was conducted according to the requirements outlined in the
International Standards 14040 and 14044 (ISO, 2006a, 2006b). The present Section provides
a detailed description of the LCA methodology utilized for the study: the goal of the LCA, func-
tional unit and reference flow, the system boundaries, the choices for the modelling approach
for addressing multi-functionality, the modelling tools, data requirements, impact assessment
method, assumptions and limitations.
The final receiver of the study is the Danish Environmental Protection Agency and the study
might ultimately be used for internal decision support at the Danish Environmental Protection
Agency as part of a wider range of assessments aiming at investigating possible options for
grocery carrier bags. This means that even if the report could be disclosed to third parties, the
report does not strictly comply with the standard. The reason for this lack of compliance is that
the report has undergone external peer review by COWI A/S, but not by a panel of experts
throughout the development of the project as required by the standard.
The contract for the project did not budget for extensive data collection, which means that
there were pre-specified limitations on the amount of data that could be gathered for the study.
Therefore, most of the data used are based on publicly available LCI data and data from exist-
ing LCA studies on grocery carrier bags.
3.1
LCA goal definition
The goal of this study was to provide the Danish Environmental Protection Agency with the
potential life cycle environmental impacts associated with a range of alternative types of multi-
ple-use carrier bags. The aim of the study was to:
identify the best disposal option for each carrier bag type within the identified end-of-life
options;
identify the multiple-use carrier bag alternative with the best environmental performance for
each of the investigated impact categories;
identify the number of times each multiple-use bag would need to be reused to lower the
environmental impacts connected to its production and in comparison to other carrier bag
alternatives, based on different reuse and disposal options.
The carrier bag alternatives investigated were those available for purchase in Danish super-
markets in 2017. The comparative analysis was carried out with respect to a range of envi-
ronmental impacts and taking into account three different end-of-life options: incineration,
recycling, and secondary reuse as a waste bin bag before being incinerated. The number of
reuse times was calculated as primary reuse, i.e. complying with the function for which the
carrier bag was produced. The scenarios are described in detail in Section 4.
The target audience of the LCA is the Danish Environmental Protection Agency. The study
might ultimately be used for internal decision support at the Danish Environmental Protection
Agency as part of a wider range of assessments aiming at investigating possible options for
managing waste grocery carrier bags.
3.2
Functional unit
The role of the functional unit definition in LCA is to ensure that the environmental assessment
of the products is based on a fair basis for comparison, in this case the fulfilment of the same
The Danish Environmental Protection Agency / LCA of grocery carrier bags
31
functionality. This is particularly important in the case of carrier bags, where different types and
materials can provide different functionalities in terms of number of uses, resistance to punc-
turing and tearing, resistance to water, weight holding capacity, and so on. As explained in
Section 2, different carrier bag types have different weight, and carrier bags intended to last
longer, with larger thickness and weight, commonly require more resources for their production
and therefore are likely to provide larger environmental impacts than lighter bags on a bag-to-
bag comparison.
Previous LCA studies on carrier bags have compared different carrier bag types based func-
tional unit such as “carrying grocery shopping to the home for a defined amount of time (and
amount of items) in a defined year” (i.e. Environment Agency, 2011; Environment Australia,
2002). These studies calculated the number of each type of bag required to fulfil the defined
function, where the impacts associated with multiple-use carrier bags were “discounted”,
meaning that the environmental impacts associated with these bags were divided by the num-
ber of reuse times expected for that type of bag (Edwards and Fry, 2011).
For this study, we defined a functional unit that allowed a fair basis for comparison for the
grocery carrier bags, but that also allowed to identify the number of required reuse times on
the basis of the environmental impacts associated with each bag, instead of using initial as-
sumptions on the potential carrier bag reuse time and overall lifetime. Then, the calculated
number of reuse times based on environmental performance is intended to raise the discus-
sion among the stakeholders on the effective expected lifetime of each carrier bag. The func-
tional unit chosen for this study was:
Carrying one time grocery shopping with an average volume of 22 litres and with an
average weight of 12 kilograms from Danish supermarkets to homes in 2017 with a
(newly purchased) carrier bag. The carrier bag is produced in Europe and distributed to
Danish supermarkets. After use, the carrier bag is collected by the Danish waste man-
agement system.
The functional unit chosen corresponds to carrying grocery shopping home for one shopping
with a virgin LDPE carrier bag with average characteristics. The volume and the weight for the
grocery shopping specified in the functional unit correspond to the average volume and weight
holding capacity of the carrier bag always available in all Danish supermarkets, which is virgin
LDPE. Ideally, the customer at the Danish supermarket could buy this type of bag for every
shopping. This type of functional unit allows comparing different types of carrier bags as if they
were all bought at the same time for one shopping. The volume and weight chosen allow com-
paring the other bag types to the most common carrier bag options: some carrier bags will not
fulfil the volume or weight holding requirement, therefore needing a purchase of two instead of
one.
The carrier bags considered for this study are assumed to be produced in Europe and distrib-
uted to Danish supermarkets. After being used, the bags are collected within the Danish waste
management system, which handles also the packaging required for the distribution of the
bags.
The number of reuse times for the carrier bag alternatives will be calculated as: how many
times would this alternative carrier bag type need to be reused in order to provide a better
environmental performance than an average virgin LDPE carrier bag, while fulfilling the same
function? The functional unit defined for this study did not cover prevention strategies, nor
consumer behaviour or behavioural changes. The functional unit does not target a specific
group or age of customers and does not cover typical or average shopping preferences or
behaviour.
32 The Danish Environmental Protection Agency / LCA of grocery carrier bags
3.2.1 Reference flow
The reference flow was calculated for each bag type, and it corresponded to the number of
carrier bags required to fulfil the functional unit. According to the definition provided by the
functional unit, this depended mainly on the volume of the bag and its weight holding capacity.
Volume and weight holding capacity were considered only, since we observed a direct correla-
tion between thickness and weight holding capacity. The reference flow for each carrier bag
type is provided below in Table 3. The average virgin LDPE plastic was taken as a reference.
The reference flow for each bag subtype in Table 3 was calculated taking into consideration
both volume and weight holding capacity as conditions that had to be fulfilled at the same time.
This means that, for each carrier bag, if the volume and/or the weight holding capacity were
lower than the ones specified in the functional unit, we assumed that the customers would
need to buy two bags instead of one in order to comply for the same functionality (a grocery
shopping of the volume of 22 litres and/or a weight of 12 kilograms). When a bag was required
two times, it was modelled by multiplying by two the average weight and volume provided in
Table 2. In the cases of biopolymer and paper carrier bags, the weight holding capacity sur-
veyed was in average compliant with the virgin LDPE carrier bag, but provided the highest
variance between the samples. For example, the weight that these types of bags were capable
of holding varied greatly in the tested samples, especially if the items placed in the bags for
the survey had sharp angles, which tore the bags much more easily than for other carrier bag
types (Alonso Altonaga, 2017). For these reasons, the weight holding capacity for the refer-
ence flow was considered not respected, and that two bags would be required to carry the
same weight. The reference flow for each carrier bag also differed for the material composition
used for the LCA modelling. Further details are provided in the Life Cycle Inventory (LCI; Ap-
pendix A).
Table 3. Required reference flow for each carrier bag
Reference flow
Volume
Weight holding capacity
Material Type
(number of bags
enough?
enough?
needed)
Plastic
LDPE
-
-
1 (reference bag)
Plastic
LDPE simple
No
No
2
Plastic
LDPE rigid handle
Yes
Yes
1
Plastic
LDPE recycled
No
No
2
Plastic
LDPE recycled, simple
No
No
2
Plastic
LDPE recycled, rigid
Yes
Yes
1
handle
Plastic
PP non-woven
Yes
Yes
1
Plastic
PP woven
Yes
Yes
1
Plastic
PET recycled
Yes
Yes
1
Plastic
Polyester
Yes
Yes
1
Bio-
Biopolymer
No
No
2
plastic
Paper
Paper
Yes
No
2
Textile
Cotton organic
No
Yes
2
Textile
Cotton conventional
Yes
Yes
1
Compo- Jute, PP, cotton
Yes
Yes
1
site
The Danish Environmental Protection Agency / LCA of grocery carrier bags
33
3.3
System boundaries
The time horizon of the impacts in this LCA was 100 years. The geographical scope was Eu-
rope. The temporal scope was 2017. The LCA was a “cradle-to-grave” LCA, meaning that for
each carrier bag were taken into account the environmental impacts of all its life-cycle stages,
from production of the carrier bag material, manufacturing of the carrier bag and distribution, to
use and end-of-life.
The system boundaries included production of energy and material resources required for the
production of the carrier bags, as well as production of the packaging used for the distribution
of the bags. These required resources were production of electricity and heat, production of
the main carrier bag material (such as LDPE) and ancillary materials (such as ink, glue). In
accordance with the project partners, the production of the carrier bags and the packaging for
distribution was set to occur in Europe. Production of the carrier bag material and other ancil-
lary materials could occur anywhere in the world, as the materials were assumed to be re-
trieved from the market. The carrier bags were assumed to be distributed to Danish supermar-
kets by road transportation and using cardboard packaging. Production of transportation fuel
was included in the assessment.
The assessment assumed zero emissions arising from the use phase. The LCA included the
production of energy and material resources required to collect, treat and manage the carrier
bag once it was collected by the Danish waste management system. In particular, the as-
sessment took into account direct emissions occurring to air, water and soil during the waste
management phase, as well as avoided processes (
i.e. avoided production of primary materi-
als and energy substituted by the residues). The waste management processes were set to
occur partly in Denmark (collection, transport and incineration) and partly in other European
countries (transport, recycling and final disposal of rejects).
Capital goods, as the construction of facilities and production of machineries and transporta-
tion were not included. In accordance with the project partners, the system boundaries do not
include small very lightweight plastic carrier bags and other types of carriers, such as personal
bags or bags provided by other retailers. The report does not consider behavioural changes or
consequences of introducing further economic measures. The study does not take into ac-
count economic consequences for retailers and carrier bag producers. The environmental
assessment does not take into account the effects of littering.
3.4
Modelling approach and allocation of multi-functionality
The LCA involved consequences that resulted in additionally installed (or additionally decom-
missioned) equipment/capacity outside the boundary of the foreground systems. The model-
ling approach used was consequential LCA. Multi-functionality in the model was addressed by
system expansion. This means that co-products generated along with the main service provid-
ed by the scenarios,
i.e. treatment of the residues, were assumed to displace those products
in the market that were likely to react to changes in demand/supply induced by the investigat-
ed scenarios. These technologies were referred to as “marginal technologies” and are dis-
cussed in detail in Appendix B. Examples are the energy produced from the incineration of the
waste, and recovered material from the recycling processes.
The marginal energy technologies were chosen with the project partners and are described in
detail in Appendix B. The energy marginal technologies have a future outlook and were de-
fined for the period 2020 – 2030. Since the study is going to support decisions that will occur in
a 10 year period, using a future marginal energy was assumed to represent the effects of such
choices in the future waste management system.
34 The Danish Environmental Protection Agency / LCA of grocery carrier bags
3.5
Modelling of primary reuse
Each of the carrier bags can be reused multiple times. When the carrier bag for grocery shop-
ping is used again to provide the same function, this is called primary reuse (reuse for the
same function for which the product is produced).
Primary reuse has been modelled as illustrated in Figure 10. We assumed that reuse X times
of a carrier bag allowed avoiding the corresponding use X times of another carrier bag. This
means that the avoided use of another carrier bag avoids the environmental life cycle impact
associated with its production and disposal. Disposal is indicated below generically as “EOL”
(end-of-life). The three end-of-life options taken into account for this study are described in
Section 4.
This configuration allows calculating the number of times a type of carrier bag would need to
be reused in order to provide a better environmental performance the carrier bag taken as
reference, which was LDPE. Considering the cradle-to-grave LCA result for the carrier bag A
as
LCIAA and the cradle-to-grave LCA result for the reference LDPE carrier bag as
LCIALDPE,
the number of reuse times
x is calculated as follows:
LCIA
xLCIA
LCIA
A
LDPE
LDPE
(Eq. 1)
LCIA
LCIA
A
LDPE
x
(Eq. 2)
LCIALDPE
The number of times depends on the difference between the two LCIA results, based on the
LCIA result set as reference.
The results for these calculations were provided for this report as a matrix, which represents in
the rows the alternative carrier bags, and in the column the carrier bag taken as reference.
The numbers in the cells provide the number of times an alternative carrier bag needs to be
reused in order to provide a better alternative than the carrier bag used as reference in the
column (Figure 11).
The avoided bag can in practice also be reused, and if this was the case then the reuse num-
ber X would proportionally be as many times higher as it was reused. The resulting reuse
numbers calculated with equation 2 should therefore be seen as a minimum reuse number
that could be higher.
Edwards and Fry (2011) performed a similar assessment, but calculating the number of reuse
times simply performing a ratio between the carrier bag alternative and the reference carrier
bag. Such calculation differs from the method adopted for the present study by providing the
number of reuse times, instead of the number of times the bag is used in total (Eq. 2).
3.6
Modelling of secondary reuse
Secondary reuse, i.e. reuse to provide for a function different than the one for which the prod-
uct was produced, was assumed as substituting a waste bin bag (production and disposal).
The function of the substituted waste bin bag is to hold waste with an average volume of 22.4
litres before being incinerated. The substituted waste bin bag was assumed to be an LDPE
waste bin bag; the average volume was obtained after a survey of three different types of
LDPE waste bin bags purchasable in Danish supermarkets in 2017.
The Danish Environmental Protection Agency / LCA of grocery carrier bags
35
Reuse X
Production of
Carrier bag
times
carrier bag
A
EOL
(Primary
A
(Primary use)
reuse)
Avoidance
X times
Production of
Carrier bag
carrier bag
LDPE
EOL
LDPE
(Primary use)
Figure 10. Generic modelling for the primary reuse. The example portrays the primary
reuse X times of a generic “carrier bag A”. The reuse X times allows avoiding X times
the production, use and disposal of the reference LDPE carrier bag.
X: number of times a carrier bag type
LDPE carrier bag , EOL1
in the rows needs to be reused in
Carrier bag A, EOL1
X times
order to provide the environmental
Carrier bag C, EOL1
X times
performance of the carrier bag type
in the column
Carrier bag D, EOL1
X times
Figure 11. Example of the result table that will illustrate the calculated number of prima-
ry reuse times. For each carrier bag alternative in the rows, the cells provide the num-
ber of times the carrier bag alternative needs to be reused in order to provide the envi-
ronmental performance of the reference carrier bag in the column, for a defined impact
category.
The conceptual model for secondary reuse is illustrated in Figure 12. A carrier bag produced
and purchased for grocery shopping is reused one time in order to hold waste as a waste bin
bag before being collected with residual waste and sent to incineration. The number of avoid-
ed waste bin bags (Y) was assumed to depend on the volume of the carrier bag. For example,
carrier bags with a larger volume than an average LDPE waste bin bag were assumed to be
able to contain more waste. The calculated avoided waste bin bags for each carrier bag type
are provided in Table 4.
It is noteworthy that PP, polyester, paper, cotton and composite bags cannot fully provide for
the same function as an LDPE waste bin bag. This is due to the material characteristics of the
bags, which are water permeable, while LDPE is not. Therefore, the secondary reuse of these
carrier bags has to be taken into account with due discussion. Moreover, biopolymer carrier
bags may have a lower holding capacity and lower resistance to puncturing and tearing, which
should also be taken into account for the discussion of the results.
36 The Danish Environmental Protection Agency / LCA of grocery carrier bags
Reuse 1 time
Production of
Carrier bag
as waste bag
EOL:
carrier bag
A
(Secondary
Incineration
A
(Primary use)
reuse)
Avoidance
Y times
Production of
Use of waste
EOL:
waste bin bag
bin bag
Incineration
Figure 12. Generic modelling for the secondary reuse. The example portrays the sec-
ondary avoided number Y of produced as disposed waste bin bags for the secondary
reuse of one carrier bag A.
Table 4. Number of avoided waste bin bags per carrier bag alternative.
Volume
Y: number of
Reference flow
Material
Type
available
avoided waste bin
(number of bags needed)
(L)
bags (fraction)
Plastic
LDPE
1 (reference bag)
22.4
1.0
Plastic
LDPE simple
2
38.4
1.7
Plastic
LDPE rigid handle
1
24.8
1.1
Plastic
LDPE recycled
2
43.3
1.9
Plastic
LDPE recycled, simple
2
30.0
1.3
Plastic
LDPE recycled, rigid handle
2
50.0
2.2
Plastic
PP non-woven
1
29.0
1.3*
Plastic
PP woven
1
36.7
1.6*
Plastic
PET recycled
1
42.0
1.9*
Plastic
Polyester
1
32.0
1.4*
Bioplastic Biopolymer
2
44.0
2.0*
Paper
Paper
2
46.0
2.1*
Textile
Cotton organic
2
40.0
1.8*
Textile
Cotton conventional
1
27.0
1.2*
Composite Jute, PP, cotton
1
32.0
1.4*
* The indicated carrier bag alternatives cannot fully provide for the LDPE waste bin bag functionality due to
their water permeability; the biopolymer bag could be less resistant to tearing.
3.7
Modelling tools
The study was carried out with the waste-LCA model EASETECH (Clavreul et al., 2014),
which was developed at DTU Environment and used for this assessment. EASETECH allows
modelling of the flow of material in the LCA as a mix of material fractions (e.g. plastic, paper,
etc.) and tracking their physico-chemical properties (e.g. energy content, fossil carbon, etc.)
throughout the modelled life-cycle steps. The tracking of the material composition on top of the
conventional mass flow-based LCA allows consumption and production of resources to be
based on the physico-chemical properties of the functional unit, and especially to express
emissions occurring during the end-of-life phases as a function of its chemical composition
(e.g. fossil carbon emitted during incineration).
The Danish Environmental Protection Agency / LCA of grocery carrier bags
37
3.8
LCIA methodology and types of impacts
The impact categories for the impact assessment phase were selected among those recom-
mended by the European Commission (European Commission, 2010). Since the LCA study
might ultimately be used to support decisions, we decided to provide a comprehensive set of
indicators. Previous LCA studies on grocery carrier bags have focused only on climate
change, especially for the calculation of primary reuse times. The selected impact categories
were: climate change, ozone depletion, human toxicity cancer and non-cancer effects, photo-
chemical ozone formation, ionizing radiation, particulate matter, terrestrial acidification, terres-
trial eutrophication, freshwater eutrophication, ecosystem toxicity, resource depletion, fossil
and abiotic. We also took into account depletion of water resource.
Results are presented as characterized impacts following the characterization references in
Table 5. Since characterization for the depletion of water resource is highly dependent on the
geographical location, we decided to present inventory results as litres of water resource used.
The LCIA results presented in this LCA study are relative and do not predict impacts on cate-
gory endpoints, nor threshold levels, safety margins or risk levels.
3.9
Data requirements
In order to carry out this LCA study, inventory data on the emissions connected to the produc-
tion of primary materials and energy required for the production of the different carrier bag
types were needed. Moreover, we required data on material and energy consumption for the
manufacturing of the carrier bags, as well as material needed for packaging and distribution.
Data on waste management technologies for the end-of-life of the carrier bags were also
needed.
The project did not focus on extensive data collection and was intended to be based on exist-
ing inventories for resources and data in the literature. For this reason, the study was mostly
based on data available in the Ecoinvent database, version 3.4. Ecoinvent datasets were used
for inventories for all materials and energy resources required for production, distribution, use
and disposal. In order to be consistent with the modelling approach of the study, we used the
consequential version of the database. Data on the material and energy resources required for
the production of the carrier bags was obtained from a literature review of existing LCA studies
on the environmental performance of supermarket carrier bags. Additional data on the material
composition and on the waste management technologies were obtained from the library of the
LCA model EASETECH. In general, EASETECH data and process models were used in order
to model waste incineration when it was taking place in Denmark, as well as recycling in Eu-
rope. Management of rejects from recycling outside Denmark was modelled using generic
waste management processes for Europe.
Each X in Table 6 shows the data available from LCI databases, literature sources and EA-
SETECH at the beginning of this LCA study. Data for each scenario is further specified in
Appendix A.
3.9.1 Production and distribution
Physico-chemical composition data for carrier bags products, which were needed for model-
ling incineration emissions, were obtained from the EASETECH library. The physico-chemical
composition for the biopolymer bag was obtained by modifying EASETECH data according to
physico-chemical characteristics of biopolymers from existing studies in the literature (Razza,
2014).
38 The Danish Environmental Protection Agency / LCA of grocery carrier bags
Table 5. Characterization (midpoint) references utilized in the project. The impact cate-
gory “Depletion of abiotic resources” follows the ILCD recommended characterization
factors.
Reference
Impact Category
Acronyms
LCIA method
Units
year
ILCD2011, Climate change w/o LT; mid-
kg CO
Climate change
CC
2011
2
point; GWP100; IPPC2007
eq.
ILCD2011, Ozone depletion w/o LT, ODP
kg CFC-
Ozone depletion
OD
2011
w/o LT
11 eq.
Human toxicity,
HTc
ILCD2011, Human toxicity, cancer ef-
2011
CTUh
cancer effects
fects, w/o LT, USEtox
Human toxicity, non-
ILCD2011, Human toxicity, non-cancer
HTnc
2011
CTUh
cancer effects
effects w/o LT, USEtox
Particulate mat-
ILCD2011, Particulate matter w/o LT,
kg PM2.5
ter/Respiratory inor-
PM
2011
from Humbert 2009, PM
eq.
ganics
ILCD2011, Ionising radiation human
Ionizing radiation,
kBq U235
IR
health w/o LT, IRP100 w/o LT, ReCiPe
2011
human health
eq. (to air)
1.05 midpoint (H)
Photochemical
kg
ILCD2011, Photochemical ozone for-
ozone formation,
POF
2011
NMVOC
mation, human health w/o LT, POCP
human health
eq.
Terrestrial acidifica-
ILCD2011, Terrestrial acidification, Ac-
mol H+
TA
2011
tion
cumulated Exceedance
eq.
Eutrophication ter-
ILCD2011, Eutrophication Terrestrial,
TE
2011
mol N eq.
restrial
Accumulated Exceedance
Eutrophication
ILCD2011, Eutrophication Freshwater,
FE
2011
kg P eq.
freshwater
FEP ReCiPe 1.05 midpoint (H)
Eutrophication ma-
ILCD2011, Eutrophication Marine w/o LT,
ME
2011
kg N eq.
rine
ReCiPe2008 1.05
Ecotoxicity freshwa-
ILCD2011, Ecotoxicity freshwater w/o LT,
ET
2011
CTUe
ter
USEtox
Resources, deple-
CML 2001, Depletion of abiotic re-
tion of abiotic re-
RDfos
2016
MJ
sources, fossil - updated 2016
sources, fossil
Resources, deple-
CML 2001, Depletion of abiotic re-
tion of abiotic re-
RD
sources, elements (reserve base) - up-
2016
kg Sb eq.
sources (reserve
dated 2016
base)
The manufacturing process of the carrier bag was set to occur in Europe. Inventories of emis-
sions related to the production of primary materials and energy required for the carrier bags
manufacturing phase were retrieved from the Ecoinvent database (v3.4, consequential), with
exception of recycled LDPE, PET polyester, organic cotton and composite. It was assumed
that primary materials and energy were retrieved from the market, therefore Ecoinvent “mar-
ket” inventories were utilized when available. These inventories take into account production
shares in different locations in the world. Market inventories were utilized also for the energy
(electricity and heat) required for the manufacturing of the carrier bags, but with a European
focus. Cotton bags are assumed to be manufactured in Europe, but the cotton used for the
manufacturing is assumed to be retrieved from the market. The dataset used for cotton pro-
duction (Ecoinvent, version 3.4, consequential) is based on a global average based on inputs
from China, India, Latin America, and Turkey.
The Danish Environmental Protection Agency / LCA of grocery carrier bags
39
Data on the energy and material requirements (such as amount of electricity, ancillary materi-
als, and packaging) for most of the carrier bag manufacturing processes were available from
literature. Specific data was missing for woven PP, PET, polyester, organic cotton and compo-
site carrier bags. Transportation data was available as far as fuel consumption is concerned,
but data on kilometres driven was missing, since it was not possible to locate a precise geo-
graphical location for the production of the carrier bag.
3.9.2 End-of-life
On the other hand, as far as the end-of-life phase was concerned, extensive data and dedicat-
ed process models were available for incineration and recycling through the EASETECH data-
base. Incineration in Denmark was modelled with an input-specific process in EASETECH,
which took into account also direct emissions occurring from the incineration of the material.
Utilized and recovered electricity and heat were the marginal energy technologies described in
detail in Appendix B. The management of residues from the incineration process was also
taken into account and modelled. Recycling in European countries was modelled with EA-
SETECH and according to data available in the literature. Management of residues from the
recycling process was modelled with Ecoinvent waste management processes for Europe.
Ancillary materials required in the end-of-life processes were obtained from the Ecoinvent
database, version 3.4, consequential.
Table 6. Data completeness assessment. Inventory of the available data at the begin-
ning of the LCA study (without assumptions). X in the table represents available data.
Please see Appendix A for details on data selected for the assessment and on the litera-
ture references used for the carrier bag manufacturing data.
Carrier
Physico-
Carrier bag
bag
chemical
Material pro-
Transporta-
End-of-life:
End-of-life:
manufactur-
materi-
composi-
duction data
tion data
incineration
recycling
ing data
al
tion data
X
X
X
X
Ecoinvent 3.4,
EASETECH, EASETECH,
EASETECH
LDPE
consequen-
X
Ecoinvent
Ecoinvent
(Riber et al.,
tial, global
3.4, conse-
3.4, conse-
2009)
market
quential
quential
X
X
X
EASETECH, EASETECH,
LDPE
EASETECH
Ecoinvent
Ecoinvent
recycled (Riber et al.,
3.4, conse-
3.4, conse-
2009)
quential
quential
X
X
X
X
Ecoinvent 3.4,
EASETECH, EASETECH,
PP non-
EASETECH
consequen-
X
Ecoinvent
Ecoinvent
woven
(Riber et al.,
tial, global
3.4, conse-
3.4, conse-
2009)
market
quential
quential
X
X
X
X
PP
Ecoinvent 3.4,
EASETECH, EASETECH,
EASETECH
consequen-
Ecoinvent
Ecoinvent
woven
(Riber et al.,
tial, global
3.4, conse-
3.4, conse-
2009)
market
quential
quential
X
X
X
X
Ecoinvent 3.4,
EASETECH, EASETECH,
PET
EASETECH
consequen-
Ecoinvent
Ecoinvent
recycled (Riber et al.,
tial, global
3.4, conse-
3.4, conse-
2009)
market
quential
quential
40 The Danish Environmental Protection Agency / LCA of grocery carrier bags
Table 6 (continued). Data completeness assessment. Inventory of the available data at
the beginning of the LCA study (without assumptions). X in the table represents availa-
ble data. Please see Appendix A for details on data selected for the assessment and on
the literature references used for the carrier bag manufacturing data.
Physico-
Material
Carrier bag
Carrier bag
chemical
Transporta-
End-of-life: End-of-life:
production
manufactur-
material
composi-
tion data
incineration
recycling
data
ing data
tion data
X
X
PET Poly-
EASETECH,
EASETECH
Ecoinvent
ester
(Riber et al.,
3.4, conse-
2009)
quential
X
X
X
EASETECH
Ecoinvent
EASETECH,
Biopolymer
(Razza,
3.4, conse-
X
Ecoinvent
Not recycled
2014; Riber
quential,
3.4, conse-
et al., 2009) global market
quential
X
X
X
EASETECH, EASETECH,
EASETECH
Paper
X
Ecoinvent
Ecoinvent
(Riber et al.,
3.4, conse-
3.4, conse-
2009)
quential
quential
X
X
EASETECH,
Cotton
EASETECH
Ecoinvent
Not recycled
organic
(Riber et al.,
3.4, conse-
2009)
quential
X
X
X
Cotton
Ecoinvent
EASETECH,
EASETECH
conven-
3.4, conse-
X
Ecoinvent
Not recycled
tional
(Riber et al.,
quential,
3.4, conse-
2009)
global market
quential
X
X
Composite
EASETECH,
EASETECH
(jute, PP,
Ecoinvent
Not recycled
cotton)
(Riber et al.,
3.4, conse-
2009)
quential
3.10 Assumptions
First of all, the present LCA study included in the assessment only the grocery carrier bag
types identified in the carrier bags survey (Section 2), which are carrier bag types available in
Danish supermarkets in 2017. Other carrier bags sold by other retailers, personal bags and
very lightweight carrier bags were excluded from the assessment.
In order to identify the functional unit and reference flow, we did not take into consideration
customers’ behavioural patterns, such as tendency to buy new bags for each grocery shop-
ping. We did not take into account whether differences could occur in shopping occurring at
different times of the week (weekdays versus weekends) or the size of the family unit. Effect of
taxation on customers’ behaviour or choices of the supermarkets was not included.
For biopolymer and textile bags, recycling was not considered (Table 6). For biopolymers they
do not recycle with other polymers, and are actually detrimental to the recycling of other plas-
tics. In the report we did not include negative effects from consumers that mistakenly would
place the biopolymer with the plastic recycling, therefore the result for biopolymer bags could
The Danish Environmental Protection Agency / LCA of grocery carrier bags
41
be worse if this effect was included. In addition we did not include material recovery through
composting for the compostable starch-biopolymer bags, since biopolymer bags are currently
sorted out from organic waste management plants and sent for incineration.
Recycling of textiles was not taken into account since it mainly occurs outside the Danish
waste management system, for example via charity organizations or through return schemes
at retailer shops. The extent of recovery of materials can be extremely variable according to
the specific collection selected, and the quality of the material collected.
3.10.1 Assumptions on missing data
In order to provide for the missing data identified in the completeness assessment (Table 6),
assumptions had to be made. The assumptions are reported in the following Table 7. First of
all, the material fractions used for the material composition in EASETECH were not as many
as the carrier bag types identified. We used the same material fraction for each of the three
types of material: plastic, paper and textiles.
Regarding the production of the primary materials required for the manufacturing of the carrier
bags, it was not possible to retrieve “market” production processes from Ecoinvent for all the
carrier bags materials assessed. Market inventories were not available for paper and for the
LDPE selected for the modelling of the waste bin bag. For these materials, production da-
tasets for Europe were chosen instead. A specific dataset for PET polyester production was
not available, so instead a market dataset for virgin PET was used.
Moreover, Ecoinvent did not provide inventories for the production of recycled LDPE and or-
ganic cotton. For this reason, we assumed that recycled LDPE could be modelled, as a first
assumption, utilizing the same dataset of virgin LDPE. For organic cotton, we modified the
Ecoinvent dataset for conventional cotton production by subtracting environmental impacts
connected to fertilizers and by lowering the production yield by 30 %. The yield of organic
versus conventional cotton was found to range between 20 % and 40 % in the literature, 30 %
according to a field test performed in India (Forster et al., 2013).
In order to model the production of composite material, we took into account the production of
each single material composing the composite bag, with an assumed percent share of 80%
jute, 10% PP and 10% cotton.
The available data on the manufacturing part of the carrier bags was lacking for the different
PP (woven or non-woven), PET recycled, polyester PET, organic cotton and composite. We
considered that the manufacturing materials and energy requirements were the same for wo-
ven and non-woven PP bags, as well as for PET and polyester PET. These types of carrier
bags were found having very similar characteristics from the survey conducted on carrier
bags. The same manufacturing data were used for the paper bleached and not bleached;
similarly the same production data was used for cotton conventional, organic and composite
bags (according to weight and materials used). We assumed that the packaging for shipping of
the bags was single-wall corrugated cardboard box for all carrier bag types, as found from the
conducted literature review.
We could not find literature data on the production and manufacturing of the waste bin bag.
The waste bin bags surveyed for this study were thinner and of a visibly lower quality com-
pared to the LDPE carrier bags. Due to the characteristics of the LDPE waste bin bags sur-
veyed, we assumed that the production of such bag was less demanding in terms of energy
and materials. For this reason, we decided to use the Ecoinvent dataset for the production of
LDPE packaging, which included extrusion of LDPE and ancillary materials consumption. The
Ecoinvent process chosen for waste bin bags production presented slightly lower overall im-
pacts compared to the one for the production of LDPE carrier bag.
42 The Danish Environmental Protection Agency / LCA of grocery carrier bags
The EASETECH process models for recycling were based on literature data for recycling of
plastic originating from virgin polymers, but not for recycled polymers. Therefore, we assumed
that the efficiency was the same based on material type (for example, the same efficiency for
all LDPE types).
As far as the environmental assessment is concerned, the LCA included the potential envi-
ronmental impacts arising from the material and energy requirements for the production, use
and treatment of the carrier bag, as well as the direct emissions during treatment. The LCA did
not take into consideration the environmental effects of littering, nor the environmental impacts
associated with the construction or decommissioning of infrastructures. Biomass was not con-
sidered a limited resource.
Table 7. Data assumptions with respect to carrier bag type and location in the model-
ling. X indicates where data was already present and did not require assumptions.
Physcio-
Carrier bag
Carrier bag
chemical
Material pro-
Transportation End-of-life: End-of-life:
manufactur-
material
composition
duction data
distance
incineration
recycling
ing data
data
LDPE
Soft plastic
X
X
Assumed
X
X
Same as LDPE
LDPE recy-
Ecoinvent 3.4,
Same as
Same as
Soft plastic
Assumed
X
cled
consequential,
LDPE
LDPE
global market
PP non-
Soft plastic
X
X
Assumed
X
X
woven
Same as PP
PP woven
Soft plastic
X
Assumed
X
X
non-woven
PET recy-
Same as
Soft plastic
X
Assumed
X
X
cled
LDPE
Virgin PET
Ecoinvent 3.4,
Same as PP
Same as
Polyester
Soft plastic
Assumed
X
consequential,
non-woven
PET
global market
Soft plastic,
Biopolymer
X
X
Assumed
X
Not recycled
modified
X
Paper and
Ecoinvent 3.4,
Paper
consequential,
X
Assumed
X
X
carton
production in
Europe
Modified from
Same as
Cotton or-
Textiles
cotton conven-
cotton con-
Assumed
X
Not recycled
ganic
tional
ventional
Cotton con-
Textiles
X
X
Assumed
X
Not recycled
ventional
Ecoinvent 3.4,
Composite
consequential,
Same as
(jute, PP,
Textiles
global market,
cotton con-
Assumed
X
Not recycled
cotton)
share between
ventional
materials
The Danish Environmental Protection Agency / LCA of grocery carrier bags
43
3.11 Data quality assessment
The information regarding volume, weight holding capacity and weight of the carrier bags was
retrieved by a survey for all carrier bags available for purchase in Danish supermarkets in
2017 and is considered reliable and current.
Considering the same material composition for some carrier bags assessed in this study
means that in the LCA results emissions from incineration of each material type are driven by
mass rather than by different chemical composition of the bags. This will affect results mainly
for the fossil carbon content of the material, which is emitted to air through incineration.
Regarding the datasets retrieved from the Ecoinvent database, the consequential version of
the database is considered consistent with the goal and scope of this LCA study. The version
of the database employed for this LCA was the latest available (3.4). All datasets used for this
study have been tested for their environmental impacts against other datasets for similar mate-
rials and energy before being selected and implemented in the modelling. For example, we
downloaded all available datasets for LDPE (market, production in various geographical loca-
tions) and verified that the dataset chosen for the modelling presented overall values in line
with other similar datasets. In general, market and global datasets provided slightly higher
emissions than production datasets in specific geographical locations. Therefore, the carrier
bags for which only production datasets were available are likely to have slightly lower emis-
sions than using market datasets. Assuming that the carrier bag manufacturers retrieve mate-
rials and energy from the market, our preference was always for the market datasets. When
not available, we used production datasets, preferably for Europe.
Specific manufacturing data for recycled LDPE, woven PP, recycled PET, polyester, bleached
paper, organic cotton and textile carrier bags were missing and available data from the most
similar carrier bags manufacturing process was assumed instead. These assumptions are not
considered limiting for the results since past LCAs on grocery carrier bags have evidenced
that most of the production impacts were ascribable to the production of the carrier bag mate-
rial (Edwards and Fry, 2011; Kimmel and Cooksey, 2014).
The data utilized to model material and energy requirements during the manufacturing pro-
cesses were retrieved from a series of well-documented LCA studies. For our references, we
gave priority to reviewed LCA studies and LCAs carried out by institutional bodies and with a
similar geographical scope (Europe). The manufacturing data was obtained as a range from
the values found in the literature, as reported in detail in Appendix A. When manufacturing
data for specific carrier bags were missing, as in the case of PET and PP bags, we utilized
data of peer-reviewed LCA studies for bags with similar characteristics.
The assumption of modelling the waste bin bag as an LDPE with lower quality was considered
in line with the intended use of the bag: the LDPE carrier bags are intended for multiple uses,
while the waste bin bag is intended for single use. Moreover, selecting a process with slightly
lower impacts for the production of the waste bin bag allows being more conservative regard-
ing the results, since lower benefits will arise from the saving of a waste bin bag.
The assumed transportation distances, which were the same for all the assessed carrier bags,
reflect that transportation could occur to be as far as southern Europe. This was considered
conservative, since the exact locations of the recycling plants were not known.
Data for end-of-life is considered technologically reliable. EASETECH allows modelling waste
management as input-specific and allows following the material flow. Values characterizing the
end-of-life processes are based on peer-reviewed literature and are extensively reported in
Appendix A. Regarding the missing data for the recycling of recycled polymer, the recovery
efficiencies could be lower if the quality of the polymer sent to recycling was lower, but we did
44 The Danish Environmental Protection Agency / LCA of grocery carrier bags
not have data to substantiate assumptions on lower recovery rates and higher residues pro-
duction for recycled polymers.
3.11.1 Critical assumptions
Overall, the present LCA study involved a series of assumptions. The following assumptions
were considered critical for the outcomes of the study:
The reference flow was calculated assuming that two bags were required when one carrier
bag could not provide for the same volume and weight holding capacity of an average LDPE
carrier bag, which was taken as reference. The study assumes that the customers of Danish
supermarkets would need to buy another bag of the same type in order to provide for the
same functionality (rounding). For some carrier bags this assumption could result in a large
overcapacity.
The recycled LDPE carrier bag was modelled using the same production dataset of virgin
LDPE. This modelling choice, due to unavailability of data, is considered to be conservative.
Recycled LDPE is expected to provide lower environmental impacts than virgin LDPE, as it
can be observed for recycled HDPE and recycled PET in comparison with virgin HDPE and
virgin PET (please see Appendix B).
The yield of organic cotton farming was assumed 30 % lower than conventional cotton. For
the modelling, this implies that 30 % more impacts are considered for the production of or-
ganic cotton than conventional cotton. The yield was found to vary in the literature between
20 % and 40 % and according to the geographical location (Forster et al., 2013). Since the
Ecoinvent dataset for cotton production is not linked to a specific geographical location, but
is based on a global average, 30 % was considered as average value. The selected value
influences the contribution of the production process to the overall impacts related to the or-
ganic cotton carrier bag.
Although the functional unit is based on carrier bags available for purchase in Danish su-
permarkets in 2017, the study is assumed to support decisions that will occur in a 10 year
period, using a future marginal energy is assumed to well represent the effects in the future
waste management system. Using a non-future marginal energy would have entailed having
coal in the energy mix, and would have provided higher savings from energy recovery in the
incineration process.
Recycling was not considered for biopolymer and textile bags. Considering recycling feasi-
ble would mean allowing for the recovery of these materials through separate collection and
re-processing, therefore lowering the impacts connected to the production of the carrier
bags.
Reuse as waste bin bag was modelled for all carrier bags included in the study, even if
some carrier bags may not be able to provide for the same functionality of an LDPE waste
bin bag.
Some of these critical assumptions were considered for sensitivity analysis, as explained in
the Life Cycle Interpretation Section.
3.12 Cut-offs
As presented in the scope Section, the assessment did not include construction and decom-
missioning of infrastructure, buildings, machinery (capital goods), or analyses of existing ca-
pacities/new capacities requirements.
3.13 Limitations
The assumptions and cut-offs listed above were not considered limiting for the results of the
assessment. First of all, the choice of the functional unit and reference flow was intentional for
the calculation of the number of primary reuse times, regardless of the consumers’ behavioural
patterns. Nevertheless, a different reference flow will be taken into consideration for a sensi-
tivity analysis of the results.
The Danish Environmental Protection Agency / LCA of grocery carrier bags
45
The choice of limiting the scope of the LCA to grocery carrier bags and not to personal bags
and bags sold from other retailers was necessary in order to provide a specific assessment of
the carrier bags available for purchase in Danish supermarkets, and to provide specific guid-
ance to retailers on the choice of the carrier bags based on their environmental performance.
The choice of using the same material fractions for plastic bags, paper bags and textile bags
will influence only the impacts that are modelled in EASETECH as a function of the material
composition. In the case of the scenarios modelled in this assessment, the choice of material
fractions will influence the emissions to atmosphere during incineration. Therefore, identifying
the fossil and non-fossil carbon content and the content of metals emitted to air of the material
fractions can cover the input-dependent part of the results.
Finally, littering effects were considered negligible for Denmark. Littering was mentioned in
Environment Australia (2002) as an effect of wind blowing on landfills and as a result of
missed environmental education.
3.14 Life Cycle Interpretation
The Life Cycle Interpretation part of this study comprises the analysis of the results, which are
provided both as characterized and normalized impacts, and the discussion of such results.
The analysis of the results was carried out with respect to the three main aims stated in the
goal of the study: (1) identification of the best disposal option for each type of bag, (2) identifi-
cation of the carrier bag with the best environmental performance, and (3) identification of the
required number of primary reuse times based on the environmental assessment. The com-
parison of results was carried out per impact category and without employing any weighting.
1. Identification of the best disposal option for each type of bag
For each type of carrier bag and impact category at a time, we examined the character-
ized results for each of the end-of-life scenarios. The LCIA for each bag was assessed
with a contribution analysis, which identified the parts of the LCA model contributing the
most to the final results. We also provided a dedicated contribution analysis to the carrier
bag manufacturing part. This part of the interpretation of the results provided indication of
the most preferable disposal option for each carrier bag type based on the results of the
environmental assessment.
2. Identification of the carrier bag with the best environmental performance
For each impact category, we identified the carrier bag alternative and the end-of-life sce-
nario that provides the best environmental performance, as well as whether the identified
environmental performance was significantly better than the one provided by the other
carrier bag alternatives. The optimal end-of-life scenario identified in (1) was taken into
account for the discussion of the results.
3. Identification of the number of primary reuse times
As explained in the Section on modelling of primary reuse, we provided the calculated
number of primary reuse times required by a carrier bag alternative to provide a better en-
vironmental performance than a reference carrier bag. The number of reuse times was
calculated for each impact category and differences were discussed.
The results were discussed with respect to the goal and scope of the study, as well with re-
spect to the limitations and considerations about data quality.
The discussion of the results was supported by additional calculations carried out as scenario
analysis. A scenario analysis is a sensitivity analysis that takes into account the variation in the
final result that occurs with differences in the initial assumptions taken. In particular, the varia-
tion in the results obtained was observed with respect to:
46 The Danish Environmental Protection Agency / LCA of grocery carrier bags
different reference flow: not rounded to two bags but based on fractions that fulfil the weight
and volume criteria;
secondary reuse allowed for all carrier bag types versus only carrier bags that can fully pro-
vide for the waste bin bag functionality;
25 % lower impacts associated to virgin LDPE production.
3.15 Critical review
This LCA study includes a critical review, carried out by Line Geest Jakobsen and Trine Lund
Neidel from COWI A/S in January 2018. The aim of the critical review is to assess the compli-
ance of the LCA study with the ISO standard and to increase the clarity and usefulness of the
result.
Although this LCA might be used to support decisions and that the comparative assertion
might ultimately be disclosed to the public, there are pre-defined limitations to the study re-
garding the fact that the critical review was not conducted while the project was being carried
out and by a panel of interested parties. For this reason, the report does not fully comply with
the ISO standard. The critical review is provided in Appendix D and the main outcomes are
summarized in the Executive Summary.
3.16 Format of the report
The format of the report is:
Short executive summary in Danish (8 pages);
Short executive summary in English (7 pages);
Technical LCA report.
The Danish Environmental Protection Agency / LCA of grocery carrier bags
47
4. Scenarios
The following Section presents the scenarios that have been assessed by this LCA study. First
of all, we selected a number of alternatives from the carrier bags identified from the survey.
Then, scenarios were obtained by associating each carrier bag alternative with three different
end-of-life scenarios. The scenarios are described referring to their main technological fea-
tures. However, as anticipated in the scope section, the system boundaries also include up-
stream processes and emissions to air, water and soil related to material and energy require-
ments for the presented technologies, as well as substituted energy and products. A detailed
description of the material and energy processes used in the present study is provided in the
LCI (Appendix A).
4.1
Carrier bag alternatives
The selected carrier bag alternatives are provided in Table 8. The virgin LDPE type was se-
lected as reference, since it represents the carrier bag that can always be found for purchase
at the cash register in all Danish supermarkets. This carrier bag alternative has been named
“LDPEavg” scenario and it constitutes an average between simple and rigid handle LDPE
carrier bags. Scenarios “LDPEs” and “LDPEh”, on the average simple and rigid handle LDPE
carrier bags, respectively, were considered as well. The rigid handle carrier bag requires more
material for its production, but has larger volume and might result in a different environmental
performance when compared in terms of the functional unit. “LDPErec” was considered for
recycled LDPE in general, since the survey could only find three items for this bag and since
the simple and rigid handle model both do not show any difference with respect to the func-
tional unit considered.
Table 8. Required reference flow for each carrier bag
Reference flow
Scenario name
Material
Type
(number of bags needed)
LDPEavg
Plastic
LDPE
1 (reference bag)
LDPEs
Plastic
LDPE simple
2
LDPEh
Plastic
LDPE rigid handle
1
LDPErec
Plastic
LDPE recycled
2
-
Plastic
LDPE recycled, simple
2
-
Plastic
LDPE recycled, rigid handle
2
PP
Plastic
PP non-woven
1
PPwov
Plastic
PP woven
1
PETrec
Plastic
PET recycled
1
PETpol
Plastic
Polyester
1
BP
Bioplastic
Biopolymer
2
PAP
Paper
Paper, unbleached
2
PAPb
Paper
Paper, bleached
2
COTorg
Textile
Cotton organic
2
COT
Textile
Cotton conventional
1
COM
Composite
Jute, PP, cotton
1
W
Plastic
LDPE
1
48 The Danish Environmental Protection Agency / LCA of grocery carrier bags
Scenarios “PP” and “PPwov” consider non-woven and woven PP, respectively. “PETrec” rep-
resents recycled PET carrier bags, while “PETpol” refers to PET polyester. The “BP” scenario
models a biopolymer bag, which was assumed to be starch-complexed biopolymer (i.e. a so-
called compostable bag, as explained in Section 2). For the paper carrier bag, an additional
scenario was added to the carrier bag “PAP”: we introduced the scenario, “PAPb”, in order to
include also the effect of utilizing bleached paper instead of unbleached paper.
“COTorg” and “COT” scenarios model organic and conventional cotton, respectively. The
difference between the two scenarios lies in the fact that organic cotton will require less ferti-
lizers to be produced, but will also have a lower yield. It was estimated that the yield was 30 %
lower, as previously seen in Section 3. “COM” scenario models the composite bag case,
where the carrier bag is made of a mix of materials: jute, PP, and cotton.
Production of
End-of-life
packaging
Col ection
Transport
packaging
material
Production of
Manufacture
carrier bag
Transport
Use
of carrier bag
material
End-of-life
Treatment
carrier bag
Col ection
residues
(EOL1/EOL2/
EOL3)
PRO – Production of material and manufacturing of bag, treatment of residues
DIS – Distribution: packaging production and transportation of carrier bag to supermarkets
USE – Use of carrier bag
DIS EOL – Treatment of packaging residues
EOL – End-of-life of carrier bag
Figure 13. General common structure for all carrier bag scenarios assessed in this LCA
study. The colour scales assigned to the different parts of the cradle to grave model will
be used also for the contribution analysis.
After being used by the customer, the carrier bag had three different end-of-life options (end-
of-life, orange): ending up in the residual waste collection and being incinerated (EOL1); being
separately collected within similar materials waste stream and sent to recycling (EOL2); or
being reused as a waste bin bag one time before ending up in the residual waste stream and
being incinerated (EOL3). The following Sections illustrate the different end-of-life options.
The Danish Environmental Protection Agency / LCA of grocery carrier bags
49
4.2
End-of-life scenarios
This Section introduces the three main end-of-life scenarios considered for this project and
indicates which carrier bags are associated with which end-of-life scenarios.
4.2.1 Incineration: EOL1
The carrier bag is produced and provided in Danish supermarkets. Here it is purchased and
used for its primary function, which is carrying grocery shopping from the supermarkets to
homes (primary use). After being used, the carrier bag is disposed in the residual waste, col-
lected and ultimately incinerated in Denmark. The electricity and heat produced during the
incineration process allows for avoiding the production of the same amount of electricity and
heat from other resources. This scenario will be further referred to as “EOL1”. The main fea-
tures of the EOL scenario are provided in Figure 14 below. The colour scale is the same as
Figure 13. Details are provided in Appendix A.
Residual
Production of
Carrier bag
Electricity and
Collection
waste
electricity and
(Primary use)
heat
incineration
heat
Figure 14. General EOL1 scenario structure. Dashed lines indicate substituted energy.
4.2.2 Recycling of material: EOL2
After being used for its primary function, the carrier bag is disposed with separately collected
waste material of the same type. The separately collected waste is sorted and sent to material
recycling, which is assumed to occur in Europe, but not in Denmark. The recycled secondary
material allows avoiding the production of the same amount of material from primary re-
sources. The residues from the recycling process are incinerated, allowing for the production
of electricity and heat, which substitute the production of the same amount of electricity and
heat from other resources. This scenario will be further referred to as “EOL2”. The main fea-
tures of the scenario are provided in Figure 15. The colour scale is the same as Figure 13.
Details are provided in Appendix A.
Primary
Secondary
Carrier bag
Col ection
Recycling
material
material for
(Primary use)
and transport
(EU)
production for
market
market
Residues
Production of
Electricity and
incineration
electricity and
heat
(EU)
heat
Figure 15. General EOL2 scenario structure.
50 The Danish Environmental Protection Agency / LCA of grocery carrier bags
4.2.3 Reuse as waste bin bag: EOL3
The carrier bag is produced and provided in Danish supermarkets. Here it is purchased and
used for its primary function, which is carrying grocery shopping from the supermarkets to
homes (primary use). After being used, the carrier bag is reused for another function, which is
collecting residual waste (secondary reuse). The carrier bag used as a waste bin bag allows
avoiding the production and disposal of a traditional waste bin bag. In both cases, the electrici-
ty and heat produced during the incineration process allow for avoiding the production of the
same amount of electricity and heat from other resources. This scenario will be further referred
to as “EOL3”. The main features of the scenario are provided in Figure 16. The colour scale is
the same as Figure 13. Details are provided in Appendix A.
Waste bin
Residual
Production of
Carrier bag
bag
Electricity and
Col ection
waste
electricity and
(Primary use)
(secondary
heat
incineration
heat
reuse)
Residual
Production of
Production of
Waste bin
Electricity and
Col ection
waste
electricity and
waste bin bag
bag
heat
incineration
heat
Figure 16. General EOL3 scenario structure.
Table 9 indicates which carrier bags alternatives are associated with which end-of-life scenar-
io. EOL1 occurs for all carrier bag options, while recycling was not supposed to occur for bi-
opolymer, cotton and composite bags. Recycling of polyester could only be assumed.
Table 9. Disposal options considered for each type of carrier bag included in the LCA
study. X in the Table indicates where an end-of-life scenario in the column is consid-
ered viable and modelled for the corresponding carrier bag alternative in the row. *
indicates functionality not fully provided.
Carrier bag alternative
EOL1
EOL2
EOL3
LDPEavg
X
X
X
LDPEs
X
X
X
LDPEh
X
X
X
LDPErec
X
X
X
PP
X
X
X*
PPwov
X
X
X*
PETrec
X
X
X*
PETpol
X
X
X*
BP
X
X*
PAP
X
X
X*
PAPb
X
X
X*
COTorg
X
X*
COT
X
X*
COM
X
X*
W
X
As introduced in the previous section, recycling of biopolymer and textiles was not considered
feasible in this study. The exclusion of recycling for textiles and biopolymers means that carrier
bags of these materials will only be tested for EOL1 and EOL3.
The Danish Environmental Protection Agency / LCA of grocery carrier bags
51
The secondary reuse as a waste bin bag was modelled for all carrier bag options. However, as
previously explained in Section 3, the functionality of an LDPE waste bin bag cannot be fully
provided by bags that are permeable to water, such as PP, polyester, paper, cotton and com-
posite. Moreover, biopolymer bags may present a higher chance of puncturing and tearing.
EOL3 for these carrier bag types was calculated and then further discussed in the discussion
section.
4.3
Carrier bag scenarios
For all carrier bag scenarios, the manufacturing stage was assumed to occur in Europe. The
produced carrier bags were distributed with single-wall corrugated cardboard packaging, and
transported from their place of production in Europe to Denmark, where they were put into use
in supermarkets. The packaging was assumed to be separately collected with cardboard
packaging, and to be transported abroad (Europe) for recycling. The carrier bag alternatives
were tested for the end-of-life scenarios as shown in Table 9. For EOL1 and EOL3, residual
waste was collected and incinerated in Denmark. For EOL2, the carrier bags were separately
collected and sorted (30 % sorted out as residues) in Denmark, then transported and recycled
in Europe.
4.3.1 LDPE carrier bags: LDPEavg, LDPEs, LDPEh, LDPErec
LDPE carrier bags include virgin LDPE carrier bags (LDPEavg, LDPEs, LDPEh), and recycled
LDPE carrier bags (LDPErec). The bags were associated with the same material composition
(soft plastic, Riber et al., 2009) and to the same manufacturing data; the scenarios differed for
the weight associated with each bag and the number of bags required to fulfil the function
expressed in the functional unit. The scenarios included the production of LDPE required for
the manufacturing of the bag, as well as ancillary materials and energy. The manufacturing of
the carrier bag produced around 5 % residues of LDPE from the initially required mass, which
were assumed to be incinerated. Recycling of LDPE in EOL2 (9.7 % residues) was assumed
to substitute LDPE production as granulate in Europe with a market response of 90 %. Resi-
dues were assumed to be incinerated in Europe.
4.3.2 PP carrier bags: PP, PPwov
PP carrier bags include non-woven (PP) and woven (PPwov) carrier bags. The bags were
associated with the same material composition (soft plastic, Riber et al., 2009) and to the
same manufacturing data; the scenarios differed for the weight associated with the carrier
bags. The scenarios included the production of PP required to manufacture the bags, as well
as energy and material requirements. 5 % of PP was assumed to be lost during production
and to be incinerated. Recycling of PP in EOL2 (9.7 % residues) was assumed to substitute
PP production as granulate in Europe with a market response of 90 %. Residues were as-
sumed to be incinerated in Europe.
4.3.3 Recycled PET carrier bags: PETrec
Recycled PET carrier bags were associated with the material composition of soft plastic (Riber
et al., 2009) and to the manufacturing consumption data of PP bags, due to the similarity in
shape and structure. The scenario included the production of recycled PET. During manufac-
turing, 5 % of material was assumed to be lost as residues, which were incinerated. The recy-
cling process in EOL2 (24.5 % residues) was assumed to produce recycled PET and to substi-
tute recycled PET granulate, amorphous, in Europe with a market response of 81 %. Residues
were assumed to be incinerated in Europe.
4.3.4 Polyester carrier bags: PETpol
Polyester carrier bags were also assumed representable by the material fraction soft plastic
(Riber et al., 2009). The scenario included production of PET polyester, which was assumed
ascribable to that of virgin PET. Due to the characteristics of the bag observed in the survey,
energy and materials needed for manufacturing were assumed the same as PP carrier bags.
52 The Danish Environmental Protection Agency / LCA of grocery carrier bags
The manufacturing process was assumed to produce 5 % residues, which were incinerated.
The recycling process in EOL2 was assumed to be similar to that of PET, with 24.5 % residues
produced and with a market response for recycled polyester of 81 %. Residues were assumed
to be incinerated in Europe.
4.3.5 Starch-complexed biopolymer bags: BP
The material composition for starch-complexed biopolymer bags was obtained from Razza,
(2014). The scenario included production of the biopolymer and manufacturing of the carrier
bag. The Ecoinvent dataset for the production of starch-complexed biopolymer does not take
into account carbon storage. Residues (1 %) were assumed to be incinerated. The recycling
scenario was not considered for this type of carrier bags, and should be avoided as it can be
detrimental to recycling of other plastic types.
4.3.6 Paper bags: PAP, PAPb
Paper carrier bags comprise unbleached (PAP) and bleached (PAPb) craft paper bags. Both
scenarios were associated with the material composition of paper and carton containers (Riber
et al., 2009) and to the same energy and material requirements for manufacturing. The sce-
narios differed for the material production process associated with unbleached and bleached
craft paper. Production was assumed to produce 5 % residues, which were incinerated. Recy-
cling in EOL2 (9 % residues) was assumed to produce craft liner for cardboard production,
with a market substitution in Europe of 90 %. Residues were assumed to be incinerated.
4.3.7 Cotton bags: COTorg, COT
Cotton bags comprise organic (COTorg) and conventional (COT) cotton. Both carrier bag
types were modelled as textiles materials (Riber et al., 2009). The scenarios differed for the
weight associated with the carrier bag, the number of bags required to fulfil the functional unit
and for the cotton production data. Organic cotton production was modelled by subtracting
fertilizers production data from conventional cotton production data and by lowering the yield
by 30 %. Residues from production (1 %) were assumed to be landfilled. The recycling scenar-
io was not considered for this type of carrier bag. If the bags were recycled it would lower the
impact of using the cotton bags. It would though be important what material the cotton would
substitute for the overall performance.
4.3.8 Composite bags: COM
The carrier bag composed of jute, PP and cotton was associated with the material fraction
textiles (Riber et al., 2009). The material production data of jute, PP and cotton was included
in the production inventory, as well as materials and energy requirements (assumed the same
as those of the cotton bags). Based on the survey, we assumed that the composition of the
bag was 80% jute, 10% PP and 10% cotton. Residues from production (1 %) were assumed to
be landfilled. The recycling scenario was not considered for this type of carrier bag.
4.3.9 LDPE waste bin bag
The LDPE waste bin bag production and disposal via incineration was modelled in order to be
used as avoided production in EOL3. The bag was modelled as soft plastic material (Riber et
al., 2009) and its production was associated with the process of extrusion of plastic, due to the
simplicity of the carrier bag. 5 % residues during production were assumed to be incinerated.
The Danish Environmental Protection Agency / LCA of grocery carrier bags
53
5. Life Cycle Impact
Assessment
5.1
Results for each carrier bag
This Section presents the characterized result scores for each carrier bag type and end-of-life
scenario. The characterized result scores are presented in Tables 10 – 12 below, one for each
end-of-life scenario. The LCIA results are relative and do not predict impacts on category end-
points, nor threshold levels, safety margins or risk levels. In order to facilitate the interpretation
of the results, results for the same type of carrier bags have been grouped and discussed in
detail in dedicated paragraphs. The results are subdivided according to the contribution of
production, distribution, use, and end-of-life of packaging and carrier bag to the overall results.
The colour scale of the contribution analysis in the following figures in this Section follows the
same colour scale of Figure 4 in Section 4. The contribution analyses for materials and energy
requirements in the manufacturing phase for each carrier bag are provided in table format.
54 The Danish Environmental Protection Agency / LCA of grocery carrier bags
Table 10. Characterized result scores for all carrier bag types, for the EOL1 end-of-life option (incineration). Results are provided per reference flow (see Table 8).
Impact category
io
CC
OD
HTC
HTNC
PM
IR
POF
TA
TE
FE
ME
ET
RD fos
RD
Water
kg
kg
kg
kBq
kg NM
mol
mol
kg
kg
kg
Scenar
CTUh
CTUh
CTUe
MJ
L
CO
CFC11eq
2 eq
PM2.5 eq U235 eq
VOC
H+ eq
N eq
P eq
N eq
Sb eq
LDPEavg
1.1E-01
1.2E-09
1.3E-09
-1.1E-08
1.6E-05
6.0E-04
2.0E-04
1.1E-04
8.7E-05
-5.6E-07
2.3E-05
7.1E-02
1.7E+00
1.9E-06
4.4E-02
LDPEs
1.7E-01
1.7E-09
2.0E-09
-1.7E-08
2.3E-05
8.9E-04
2.9E-04
1.7E-04
1.3E-04
-8.3E-07
3.4E-05
1.1E-01
2.5E+00
2.7E-06
6.5E-02
LDPEh
1.3E-01
1.4E-09
1.6E-09
-1.3E-08
1.9E-05
7.3E-04
2.3E-04
1.4E-04
1.0E-04
-6.8E-07
2.8E-05
8.6E-02
2.0E+00
2.2E-06
5.3E-02
LDPErec
2.3E-01
2.7E-09
2.8E-09
-2.3E-08
3.5E-05
1.3E-03
4.1E-04
2.5E-04
2.0E-04
-8.7E-07
5.0E-05
1.5E-01
3.5E+00
3.8E-06
5.3E-02
PP
6.5E-01
5.0E-08
2.6E-09
-5.4E-08
1.1E-04
8.7E-03
9.3E-04
5.8E-04
9.6E-04
1.1E-05
1.8E-04
2.7E-01
1.0E+01
2.3E-06
7.8E-01
PP
5.6E-01
4.4E-08
2.2E-09
-4.7E-08
9.4E-05
7.5E-03
8.1E-04
5.0E-04
8.3E-04
9.9E-06
1.5E-04
2.3E-01
9.0E+00
2.0E-06
6.8E-01
wov
PET
7.7E-01
6.4E-08
7.0E-09
-1.6E-08
2.7E-04
1.4E-02
9.6E-04
1.1E-03
1.9E-03
3.8E-05
2.2E-04
5.1E-01
1.2E+01
2.1E-05
1.4E+00
rec
PET
2.6E-01
2.2E-08
2.4E-09
-5.3E-09
9.8E-05
4.6E-03
3.3E-04
4.0E-04
6.9E-04
1.4E-05
8.9E-05
1.7E-01
4.1E+00
7.3E-06
4.7E-01
pol
BP
9.0E-02
1.5E-08
2.3E-09
3.1E-08
1.2E-04
3.8E-03
3.4E-04
7.4E-04
1.4E-03
1.6E-05
2.4E-04
1.3E-01
2.9E+00
5.1E-06
2.2E-02
PAP
6.0E-02
1.2E-08
1.5E-09
8.9E-08
1.7E-04
6.2E-03
3.5E-04
4.2E-04
1.1E-03
1.7E-05
1.4E-04
2.0E-01
1.2E+00
3.8E-05
3.4E-01
PAP
1.8E-01
2.7E-08
1.6E-09
2.4E-09
2.9E-04
3.7E-03
4.6E-04
5.8E-04
1.4E-03
8.1E-06
1.7E-04
1.3E-01
3.6E+00
5.1E-06
2.4E-01
b
COM
1.8E+00
1.2E-06
4.3E-08
-1.8E-07
2.9E-03
4.0E-02
4.8E-03
1.1E-02
3.4E-02
2.4E-04
2.5E-03
4.4E+00
2.9E+01
3.2E-05
5.5E+00
COTorg
1.1E+01
2.8E-05
4.9E-07
1.6E-06
1.1E-02
3.8E-01
2.5E-02
5.7E-02
1.4E-01
1.4E-03
9.7E-03
3.3E+01
2.0E+02
4.4E-04
7.6E+01
COT
3.9E+00
1.0E-05
1.7E-07
5.6E-07
3.8E-03
1.3E-01
8.7E-03
2.0E-02
4.9E-02
4.8E-04
3.4E-03
1.2E+01
7.2E+01
1.6E-04
2.7E+01
W
3.9E-02
-2.4E-10
1.9E-10
-4.1E-09
6.1E-06
1.9E-04
6.9E-05
3.8E-05
4.1E-05
-1.6E-07
7.5E-06
2.0E-02
6.0E-01
2.6E-07
2.4E-02
The Danish Environmental Protection Agency / LCA of grocery carrier bags
55
Table 11. Characterized result scores for all carrier bag types, for the EOL2 end-of-life option (recycling). Results are provided per reference flow (see Table 8).
Impact category
io
CC
OD
HTC
HTNC
PM
IR
POF
TA
TE
FE
ME
ET
RD fos
RD
Water
Scenar
kg
kg
kg
kBq
kg NM
mol
mol
kg
kg
kg
CTUh
CTUh
CTUe
MJ
L
CO2 eq
CFC11 eq
PM2.5 eq
U235 eq
VOC
H+ eq
N eq
P eq
N eq
Sb eq
LDPEavg
8.2E-02
5.6E-09
1.3E-09
-4.3E-10
3.0E-05
1.7E-03
1.7E-04
1.7E-04
2.7E-04
7.9E-07
3.3E-05
9.1E-02
1.3E+00
2.1E-06
8.6E-02
LDPEs
1.2E-01
8.3E-09
1.9E-09
-6.4E-10
4.4E-05
2.6E-03
2.6E-04
2.5E-04
4.0E-04
1.2E-06
4.9E-05
1.3E-01
2.0E+00
3.1E-06
1.3E-01
LDPEh
9.8E-02
6.7E-09
1.6E-09
-5.2E-10
3.6E-05
2.1E-03
2.1E-04
2.0E-04
3.3E-04
9.5E-07
3.9E-05
1.1E-01
1.6E+00
2.6E-06
1.0E-01
LDPErec
1.7E-01
1.2E-08
2.7E-09
-5.6E-10
6.5E-05
3.6E-03
3.6E-04
3.7E-04
5.8E-04
1.9E-06
7.0E-05
1.9E-01
2.8E+00
4.4E-06
9.6E-02
PP
5.0E-01
7.5E-08
3.2E-09
1.2E-08
2.1E-04
1.5E-02
9.8E-04
1.2E-03
2.4E-03
1.9E-05
2.6E-04
4.0E-01
8.9E+00
4.1E-06
1.0E+00
PP
4.4E-01
6.5E-08
2.8E-09
1.0E-08
1.9E-04
1.3E-02
8.5E-04
1.0E-03
2.1E-03
1.6E-05
2.3E-04
3.5E-01
7.7E+00
3.5E-06
9.0E-01
wov
PET
6.6E-01
8.7E-08
6.4E-09
3.0E-08
3.3E-04
1.7E-02
1.2E-03
1.6E-03
3.1E-03
3.4E-05
3.0E-04
8.7E-01
1.2E+01
1.7E-05
1.3E+00
rec
PET
2.1E-01
2.8E-08
2.0E-09
9.4E-09
1.1E-04
5.5E-03
3.7E-04
5.1E-04
1.0E-03
1.1E-05
1.1E-04
2.9E-01
3.6E+00
5.2E-06
4.1E-01
pol
BP
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
PAP
1.1E-01
1.9E-08
1.7E-09
9.7E-08
2.5E-04
8.1E-03
4.4E-04
6.5E-04
1.6E-03
1.8E-05
1.6E-04
2.6E-01
2.2E+00
3.7E-05
1.6E+00
PAP
2.3E-01
3.3E-08
1.8E-09
1.1E-08
3.7E-04
5.6E-03
5.5E-04
8.0E-04
1.9E-03
8.9E-06
1.9E-04
1.8E-01
4.6E+00
4.8E-06
1.5E+00
b
COM
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
COTorg
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
COT
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
56 The D
anish Environmental Protection Agency / LCA of grocery carrier bags
Table 12. Characterized result scores for all carrier bag types, for the EOL3 end-of-life option (secondary reuse as a waste bin bag). Results are provided per refer-
ence flow (see Table 8).
Impact category
io
CC
OD
HTC
HTNC
PM
IR
POF
TA
TE
FE
ME
ET
RD fos
RD
Water
kg
kg
CTU
CTU
kg
kBq
kg NM
mol
mol
kg
kg
kg
Scenar
CTUe
MJ
L
CO2 eq
CFC11 eq
h
h
PM2.5 eq
U235 eq
VOC
H+ eq
N eq
P eq
N eq
Sb eq
LDPE
7.2E-02
1.4E-09
1.1E-09
-7.1E-09
9.6E-06
4.2E-04
1.3E-04
7.5E-05
4.6E-05
-4.1E-07
1.6E-05
5.2E-02
1.1E+00
1.6E-06
2.0E-02
avg
LDPE
9.8E-02
2.2E-09
1.6E-09
-9.5E-09
1.3E-05
5.7E-04
1.7E-04
1.0E-04
5.8E-05
-5.6E-07
2.1E-05
7.2E-02
1.5E+00
2.3E-06
1.7E-02
s
LDPE
9.1E-02
1.7E-09
1.4E-09
-8.9E-09
1.2E-05
5.2E-04
1.6E-04
9.3E-05
5.9E-05
-5.0E-07
1.9E-05
6.4E-02
1.4E+00
1.9E-06
-5.7E-02
h
LDPE
1.6E-01
3.1E-09
2.4E-09
-1.5E-08
2.4E-05
9.4E-04
2.7E-04
1.7E-04
1.2E-04
-5.6E-07
3.5E-05
1.1E-01
2.4E+00
3.3E-06
2.9E-02
rec
PP
6.0E-01
5.1E-08
2.3E-09
-4.9E-08
1.0E-04
8.5E-03
8.4E-04
5.3E-04
9.0E-04
1.2E-05
1.7E-04
2.4E-01
9.6E+00
2.0E-06
7.6E-01
PP
5.0E-01
4.4E-08
1.9E-09
-4.0E-08
8.4E-05
7.2E-03
6.9E-04
4.4E-04
7.6E-04
1.0E-05
1.4E-04
2.0E-01
8.0E+00
1.6E-06
6.5E-01
wov
PET
6.9E-01
6.5E-08
6.7E-09
-8.5E-09
2.6E-04
1.3E-02
8.3E-04
1.0E-03
1.8E-03
3.9E-05
2.0E-04
4.7E-01
1.1E+01
2.0E-05
1.4E+00
rec
PET
2.1E-01
2.2E-08
2.1E-09
5.4E-10
8.9E-05
4.3E-03
2.4E-04
3.5E-04
6.3E-04
1.4E-05
7.8E-05
1.4E-01
3.2E+00
6.9E-06
4.5E-01
pol
BP
1.3E-02
1.5E-08
2.0E-09
3.9E-08
1.0E-04
3.5E-03
2.0E-04
6.6E-04
1.3E-03
1.7E-05
2.2E-04
9.5E-02
1.7E+00
4.6E-06
-2.6E-02
PAP
-2.1E-02
1.3E-08
1.1E-09
9.7E-08
1.6E-04
5.8E-03
2.0E-04
3.5E-04
1.0E-03
1.7E-05
1.2E-04
1.6E-01
-1.4E-02
3.7E-05
2.9E-01
PAP
1.1E-01
2.7E-08
1.2E-09
9.7E-09
2.7E-04
3.3E-03
3.4E-04
5.1E-04
1.3E-03
8.4E-06
1.6E-04
9.5E-02
2.5E+00
4.7E-06
1.9E-01
b
COM
1.7E+00
1.2E-06
4.3E-08
-1.8E-07
2.9E-03
4.0E-02
4.7E-03
1.1E-02
3.4E-02
2.4E-04
2.5E-03
4.4E+00
2.8E+01
3.2E-05
5.5E+00
COTorg
1.1E+01
2.8E-05
4.9E-07
1.6E-06
1.1E-02
3.8E-01
2.5E-02
5.7E-02
1.4E-01
1.4E-03
9.7E-03
3.3E+01
2.0E+02
4.4E-04
7.6E+01
COT
3.8E+00
1.0E-05
1.7E-07
5.7E-07
3.8E-03
1.3E-01
8.6E-03
2.0E-02
4.8E-02
4.8E-04
3.4E-03
1.2E+01
7.1E+01
1.6E-04
2.7E+01
The Danish Environmental Protection Agency / LCA of grocery carrier bags
57
5.1.1 LDPE bags: LDPEavg, LDPEs, LDPEh, LDPErec, W
The performance of LDPE carrier bags can be described with the results associated with sce-
nario LDPEavg for LDPE carrier bags with average characteristics. The contribution of produc-
tion, distribution and end-of-life to the results was proportionally the same for scenarios
LDPEs, LDPEh and LDPErec, which differed for the weight of carrier bag and number of carri-
er bags needed to fulfil the function expressed in the functional unit. The results for the climate
change impact category for LDPEavg and the three end-of-life options is presented in Figure
8, with results subdivided according to production, distribution, use and end-of-life for the
packaging and the carrier bag (contribution analysis). A dedicated contribution analysis for the
production phase for the average virgin LDPE carrier bag is presented in Table 13.
For EOL1, LDPE bags presented net impacts for the climate change impact category. 70 % of
the impacts were related to the production of the carrier bag, of which 71 % were solely related
to the LDPE material production. The second largest contribution to the climate change im-
pacts was connected to the incineration process, where the fossil carbon in the LDPE was
released to the atmosphere through air emissions. In this case, the recovery of electricity and
heat from the incineration process lead to less savings in fossil carbon emissions than the
direct emissions. Further climate change impacts were linked to the distribution phase, mostly
from the transportation of the carrier bag.
EOL2 presented net climate change impacts as well, but with a lower magnitude than EOL1.
The production and distribution phases led to the same climate change impacts as EOL1, but
the recycling of LDPE at end-of-life provided climate change savings, which were mainly as-
cribable to the recovery of LDPE as secondary material for the market and consequent avoid-
ed LDPE production. Moreover, less fossil carbon was incinerated and released to atmos-
phere. EOL3 presented lower climate change impacts than EOL1 and EOL2. The reduced net
contribution of the production and distribution phases presented in Figure 8 are due to the
subtracted impacts connected to the waste bin bag that was avoided with the secondary reuse
of the LDPE carrier bag. Emissions of carbon fossil to atmosphere were also lower due to the
prevented emissions that would have occurred with incineration of the waste bin bag.
58 The Danish Environmental Protection Agency / LCA of grocery carrier bags
Table 13. Contribution analysis for the production (PRO) processes, which included the
manufacturing of the virgin LDPE carrier bag and the management of residues obtained
during production. The Table presents the characterized result for each impact catego-
ry, with the percent contribution given by the processes involved. Results provided for
1 average LDPE carrier bag.
Result
Contributing processes: energy and ancillary materials
Impact
Unit
score
category
Virgin LDPE
Calcium
Titanium
Management
(PRO)
Electricity
Heat
Ink
production
carbonate
dioxide
residues
CC
kg CO2 eq
8.0E-02
71%
5%
8%
6%
7%
2%
2%
OD
kg CFC11
3.0E-09
12%
19%
30%
10%
26%
3%
0%
eq
HTC
CTUh
1.6E-09
37%
3%
-1%
2%
60%
1%
-1%
HTNC
CTUh
9.7E-10
76%
73%
-79%
28%
58%
5%
-61%
PM
kgPM2.5
4.1E-05
73%
9%
-2%
3%
16%
3%
-3%
eq
IR
kBq U235
5.5E-04
20%
97%
-28%
7%
8%
2%
-6%
eq
POF
kg
3.0E-04
87%
3%
1%
2%
8%
1%
-2%
NMVOC
TA
mol H+ eq
3.2E-04
83%
6%
0%
3%
12%
2%
-6%
TE
mol N eq
5.3E-04
89%
6%
0%
4%
3%
3%
-5%
FE
kg P eq
5.7E-07
24%
80%
-38%
47%
37%
18%
-68%
ME
kg N eq
5.3E-05
80%
5%
1%
4%
9%
5%
-3%
ET
CTUe
6.6E-02
56%
2%
-1%
3%
34%
1%
5%
RD fos
MJ
2.2E+00
85%
4%
6%
2%
4%
1%
-3%
RD
kg Sb eq
1.9E-06
5%
0%
0%
11%
81%
2%
0%
Water
L
3.8E-02
7%
122%
-33%
9%
5%
-2%
-7%
Climate change, LDPEavg
0,12
0,1
w
flo 0,08
nce
0,06
/ refere 0,04
eq
2 0,02
CO
kg
0
-0,02
EOL1: Incineration
EOL2: Recycling
EOL3: Reuse as bin
End-of-life scenario
PRO
DIS
USE
DIS EOL
EOL
Net
Figure 17. Characterized results for the climate change impact category and the three
end-of-life options, expressed as kg CO2 equivalents per reference flow, for the LDPE
carrier bag LDPEavg. PRO: production, DIS: distribution, USE: use; DIS EOL: end-of-
life, packaging; EOL: end-of-life, carrier bag; NET: net result.
The Danish Environmental Protection Agency / LCA of grocery carrier bags
59
Overall, the climate change results indicate that recycling an LDPE carrier bag provides lower
impacts than incinerating it. Secondary reuse as waste bin bag, however, results in more ben-
efits than recycling. This trend in the impacts could be observed also for a few other impact
categories, which are: photochemical ozone formation, human toxicity, cancer effects and
resource depletion, fossil.
The remaining impact categories also provided overall net impacts, with exception of human
toxicity, non-cancer effects, and freshwater eutrophication. In these cases savings were asso-
ciated with the recovery of electricity and heat in the incineration process. Contrarily to the
climate change impact category, recycling never provided a better result than incineration for
these impact categories. This was mostly due to the energy requirements for the recycling
process and the transportation distances to the sorting and recycling facilities and the less
energy recovered in the incineration process. Reusing the LDPE carrier bag as a waste bin
bag before incineration always provided a better environmental performance than incineration
and recycling. For all end-of-life options, the management and recycling of the cardboard
packaging used for distribution of the carrier bags did not provide a high contribution to the
results, with exception of water use.
Regarding the contribution analysis for the production phase of average virgin LDPE carrier
bag provided in Table 13 (common to EOL1, EOL2 and EOL3), the LDPE material production
data largely contributed to the impacts in most of the impact categories, together with energy
consumption. Negative scores in some impact categories are due to the use of a consequen-
tial database. Depending on the way consequential modelling is applied in Ecoinvent, the
production of some intermediate exchanges can result in the decrease of production of anoth-
er, to which is assigned a negative sign. For example, in the case of market for heat from
natural gas that was used for this project, utilization of this heat source may lead to the avoid-
ed use of other heat sources, with a negative net impact.
The trend observed for LDPEavg in the results for all impact categories was similarly observed
for all the LDPE carrier bags. Differences were due to the weight of the different carrier bag
types and the number of bags necessary to fulfil the function. Figure 9 shows the climate
change characterized results for all the LDPE carrier bag options (LDPEavg, LDPEs, LDPEh,
LDPErec) and for the waste bin bag (W, also LDPE) for EOL1. Although some carrier bags
had lower weight than the other options to which they are compared, LDPEs and LDPErec
provided higher impacts because more than one bag was required in order to provide for the
functionality expressed in the functional unit. Between LDPE carrier bags, LDPEh (LDPE with
rigid handle) provided the best environmental performance for climate change. As previously
explained in the assumptions paragraph, it was not possible to model LDPErec with recycled
LDPE data, so the virgin LDPE production data was used instead.
The trend observed for LDPEavg in the results for all impact categories was similarly observed
for all the LDPE carrier bags. Differences were due to the weight of the different carrier bag
types and the number of bags necessary to fulfil the function. Figure 9 shows the climate
change characterized results for all the LDPE carrier bag options (LDPEavg, LDPEs, LDPEh,
LDPErec) and for the waste bin bag (W, also LDPE) for EOL1. Although some carrier bags
had lower weight than the other options to which they are compared, LDPEs and LDPErec
provided higher impacts because more than one bag was required in order to provide for the
functionality expressed in the functional unit. Between LDPE carrier bags, LDPEh (LDPE with
rigid handle) provided the best environmental performance for climate change. As previously
explained in the assumptions paragraph, it was not possible to model LDPErec with recycled
LDPE data, so the virgin LDPE production data was used instead.
60 The Danish Environmental Protection Agency / LCA of grocery carrier bags
Climate change, EOL1
0,25
w 0,20
flo
nce 0,15
/ refere 0,10
eq
2
CO 0,05
kg
0,00
W
LDPEavg
LDPEs
LDPEh
LDPErec
Waste bin bag / LDPE grocery carrier bags
PRO
DIS
USE
DIS EOL
EOL
Figure 9. Characterized results for the climate change impact category, incineration
end-of-life option (EOL1) expressed as kg CO2 equivalents per reference flow, for the
LDPE carrier bags LDPEavg, LDPEs, LDPEh, LDPErec and for the LDPE waste bin bag
(W). PRO: production, DIS: distribution, USE: use; DIS EOL: end-of-life, packaging;
EOL: end-of-life, carrier bag; NET: net result.
5.1.2 PP bags: PP, PPwov
The environmental performance of PP carrier bags can be described by the characterized
results associated with PP (non-woven PP carrier bag). The results for PPwov presented the
same contribution analysis, with slightly lower magnitude, since PPwov presented a slightly
lighter weight and consequently required less material and energy for its production.
As observed for the LDPE carrier bags, climate change results presented overall net impacts.
The impacts in EOL1 (and EOL2) were mainly associated with the production of the carrier
bag, of which 69 % were associated with the production of PP (Figure 10). Emissions were
also related to the release of fossil carbon to atmosphere during incineration and transporta-
tion. Recycling of PP presented lower impacts than incineration, for the recovery of material
and lower fossil carbon release to atmosphere. EOL3 presented reduced impacts with respect
to EOL1 for the savings associated with the avoided use and disposal of the waste bin bag,
but with a small difference. The mass of avoided LDPE was proportionally lower than in the
case of LDPE carrier bags, therefore it could not reduce the production and distribution im-
pacts as in the case of LDPE carrier bags. As a consequence, recycling resulted as more
beneficial disposal option than secondary reuse. PP carrier bags were considerably heavier
than the waste bin bag, so could proportionally substitute more primary produced PP than
avoiding the production of the LDPE waste bin bag. The same trend could be observed for the
impact category resource depletion, fossil.
All the remaining impact categories presented net impacts, with exception of human toxicity,
non-cancer effects. Savings for the latter impact category were associated with the recovery of
electricity and heat in the incineration process. However, for all impact categories different
than climate change, recycling was never more beneficial than incineration, and reuse as a
waste bin bag always provided the overall best environmental performance, even if with only a
slight difference with incineration. It is worth underlining that PP carrier bags may also not fully
provide for the functionality of an LDPE waste bin bag due to their permeability to water.
The Danish Environmental Protection Agency / LCA of grocery carrier bags
61
Table 14 provides the contribution analysis for the production phase for the PP carrier bag.
Similarly to LDPE, the production of PP contributes largely to the impacts of the production
phase, but to a lower extent. Other processes contributing to the impacts of production are
electricity, heat and cotton, necessary for the cotton threads.
Table 14. Contribution analysis for the production (PRO) processes, which included the
manufacturing of the virgin PP carrier bag and the management of residues obtained
during production. The Table presents the characterized result for each impact catego-
ry, with the percent contribution given by the processes involved. Results provided for
1 PP bag.
Result
Contributing processes: energy and ancillary materials
Impact cat-
Unit
score
egory
PP pro-
Cotton
Management
(PRO)
Electricity
Heat
Water
Ink
duction
thread
residues
CC
kg CO2
4.5E-01
66%
12%
7%
0%
4%
8%
4%
eq
OD
kg
CFC11
6.0E-08
3%
13%
7%
0%
72%
4%
0%
eq
HTC
CTUh
3.5E-09
55%
16%
-3%
0%
21%
9%
1%
HTNC
CTUh
1.3E-08
23%
73%
-27%
0%
20%
10%
1%
PM
kgPM2.5 2.4E-04
59%
22%
-1%
0%
7%
14%
0%
eq
IR
kBq
8.1E-03
8%
91%
-9%
0%
7%
4%
0%
U235 eq
POF
kg
1.4E-03
81%
8%
1%
0%
3%
7%
0%
NMVOC
TA
mol H+
1.6E-03
71%
15%
0%
0%
5%
9%
0%
eq
TE
mol N
3.3E-03
69%
14%
0%
0%
6%
11%
0%
eq
FE
kg P eq
1.7E-05
40%
37%
-6%
0%
12%
16%
0%
ME
kg N eq 3.4E-04
63%
11%
1%
0%
4%
21%
0%
ET
CTUe
2.2E-01
59%
9%
-2%
0%
22%
10%
3%
RD fos
MJ
1.3E+01
79%
9%
4%
0%
2%
5%
0%
RD
kg Sb eq 2.2E-06
10%
0%
1%
0%
31%
57%
0%
Water
L
7.1E-01
2%
94%
-9%
0%
16%
-3%
0%
5.1.3 Recycled PET carrier bags: PETrec
Characterized climate change results for recycled PET carrier bags are provided in Figure 11
below. Recycled PET carrier bags showed a similar trend with respect to previously examined
fossil carbon-based carrier bags: overall net climate change impacts, which was governed by
the carrier bag production phase (80 %, Table 15).
Although PET bags were large in volume and could potentially substitute the highest fraction
of waste bin bags (Table 4), the difference between EOL1 and EOL3 was small, due to the
proportionally lower weight of the avoided waste bin bag with respect to the PET bag. Recy-
cling the PET carrier bag provided lower environmental impacts than EOL1 and EOL3 due to
the recovery of recycled PET material and lower carbon fossil emissions generated during the
incineration phase. Recycling provided an environmentally better result than incineration and
secondary reuse also for human toxicity, cancer effects, freshwater eutrophication, resource
depletion and water consumption.
62 The Danish Environmental Protection Agency / LCA of grocery carrier bags
Climate change, PP
0,7
0,6
w
flo 0,5
nce 0,4
0,3
/ refere
eq 0,2
2
CO 0,1
kg
0
-0,1
EOL1: Incineration
EOL2: Recycling
EOL3: Reuse as bin
End-of-life scenario
PRO
DIS
USE
DIS EOL
EOL
Net
Figure 10. Characterized results for the climate change impact category and the three
end-of-life options, expressed as kg CO2 equivalents per reference flow, for the PP car-
rier bag PP. PRO: production, DIS: distribution, USE: use; DIS EOL: end-of-life, packag-
ing; EOL: end-of-life, carrier bag; NET: net result.
For the remaining impact categories, recycling was worse than incineration, and reuse as
waste bin bag before incineration provided only slightly better environmental results. Savings
occur for the human toxicity, non-cancer effects impact category due to the energy recovered
during incineration.
Table 15. Contribution analysis for the production (PRO) processes, which included the
manufacturing of the recycled PET carrier bag and the management of residues ob-
tained during production. The Table presents the characterized result for each impact
category, with the percent contribution given by the processes involved. Results pro-
vided for 1 recycled PET bag.
Contributing processes: energy and ancillary materials
Result
Impact
Unit
score
Recycled
category
Cotton
Management
(PRO)
PET pro-
Electricity
Heat
Ink
Water
thread
residues
duction
CC
kg CO2
5.8E-01
80%
10%
5%
1%
3%
0%
1%
eq
OD
kg
CFC11
7.4E-08
25%
11%
6%
1%
58%
0%
0%
eq
HTC
CTUh
8.0E-09
85%
7%
-1%
1%
9%
0%
-1%
HTNC
CTUh
5.2E-08
86%
19%
-7%
1%
5%
0%
-3%
PM
kgPM2.5 4.0E-04
83%
13%
-1%
2%
4%
0%
-1%
eq
IR
kBq
1.3E-02
47%
55%
-5%
0%
4%
0%
-1%
U235 eq
kg
POF
1.5E-03
88%
8%
1%
1%
3%
0%
-1%
NMVOC
The Danish Environmental Protection Agency / LCA of grocery carrier bags
63
Table 15. (continued) Contribution analysis for the production (PRO) processes, which
included the manufacturing of the recycled PET carrier bag and the management of
residues obtained during production. The Table presents the characterized result for
each impact category, with the percent contribution given by the processes involved.
Results provided for 1 recycled PET bag.
Contributing processes: energy and ancillary materials
Result
Impact cat-
Unit
score
Recycled
egory
Cotton
Management
(PRO)
PET produc-
Electricity
Heat
Ink
Water
thread
residues
tion
mol H+
TA
2.2E-03
86%
11%
0%
1%
4%
0%
-2%
eq
mol N
TE
4.3E-03
84%
11%
0%
2%
5%
0%
-2%
eq
FE
kg P eq 4.5E-05
85%
14%
-2%
1%
5%
0%
-3%
kg N
ME
3.8E-04
84%
9%
1%
4%
4%
0%
-1%
eq
ET
CTUe
4.7E-01
67%
4%
-1%
1%
10%
0%
18%
RD fos
MJ
1.4E+01
86%
8%
4%
1%
2%
0%
-1%
kg Sb
RD
2.1E-05
95%
0%
0%
1%
3%
0%
0%
eq
Water
L
1.4E+00
49%
48%
-5%
0%
8%
0%
-1%
Climate change, PETrec
0,9
0,8
w
flo 0,7
0,6
nce
0,5
/ refere 0,4
eq
2 0,3
CO 0,2
kg 0,1
0
EOL1: Incineration
EOL2: Recycling
EOL3: Reuse as bin
End-of-life scenario
PRO
DIS
USE
DIS EOL
EOL
Net
Figure 11. Characterized results for the climate change impact category and the three
end-of-life options, expressed as kg CO2 equivalents per reference flow, for the recycled
PET carrier bag PETrec. PRO: production, DIS: distribution, USE: use; DIS EOL: end-of-
life, packaging; EOL: end-of-life, carrier bag; NET: net result.
64 The Danish Environmental Protection Agency / LCA of grocery carrier bags
5.1.4 Polyester bags: PETpol
In accordance with what already observed for other carrier bags, climate change impacts were
mostly ascribable to the carrier bag production phase (76 % of the climate change impacts, as
observed for recycled PET carrier bags). Table 16 provides the contribution analysis for the
production phase.
Table 16. Contribution analysis for the production (PRO) processes, which included the
manufacturing of the virgin PET polyester carrier bag and the management of residues
obtained during production. The Table presents the characterized result for each im-
pact category, with the percent contribution given by the processes involved. Results
provided for 1 PET polyester bag.
Contributing processes: energy and ancillary materials
Result
Impact
Unit
score
Virgin
category
Cotton
Management
(PRO)
PET pro- Electricity
Heat
Ink
Water
thread
residues
duction
CC
kg CO2
2.0E-01
76%
9%
5%
6%
3%
0%
1%
eq
OD
kg
CFC11
2.5E-08
23%
11%
6%
3%
58%
0%
0%
eq
HTC
CTUh
2.7E-09
82%
7%
-1%
4%
9%
0%
-1%
HTNC
CTUh
1.7E-08
83%
19%
-7%
3%
5%
0%
-3%
PM
kgPM2.5 1.4E-04
78%
12%
-1%
8%
4%
0%
-1%
eq
IR
kBq
4.4E-03
44%
56%
-6%
2%
4%
0%
-1%
U235 eq
POF
kg
5.0E-04
84%
8%
1%
6%
3%
0%
-1%
NMVOC
TA
mol H+
7.5E-04
81%
11%
0%
6%
4%
0%
-2%
eq
TE
mol N
1.5E-03
79%
10%
0%
8%
5%
0%
-1%
eq
FE
kg P eq
1.6E-05
81%
14%
-2%
6%
4%
0%
-2%
ME
kg N eq 1.4E-04
72%
8%
1%
16%
4%
0%
-1%
ET
CTUe
1.5E-01
63%
4%
-1%
5%
11%
0%
18%
RD fos
MJ
4.8E+00
83%
8%
4%
4%
2%
0%
-1%
RD
kg Sb eq 7.2E-06
91%
0%
0%
6%
3%
0%
0%
Water
L
4.5E-01
49%
49%
-5%
-2%
8%
0%
-1%
EOL 3 was the most favourable disposal option for climate change, while EOL1 was the worst,
due to fossil carbon emissions to air during incineration. The difference between EOL1 and
EOL3 results for climate change is due to the lower weight of the polyester bag with respect to
the recycled PET carrier bag, which therefore substitutes less material when reused as a
waste bin bag. EOL3 is the disposal option that provides the lowest impacts in most of the
impact categories assessed.
5.1.5 Comparison of fossil plastic carrier bags
The following Figure 12 aims at comparing the climate change results associated with the
fossil carbon-based grocery shopping bags that have been presented so far. The comparison
of results highlights that the lowest climate change impacts were calculated for LDPE. This
The Danish Environmental Protection Agency / LCA of grocery carrier bags
65
result is related to the fact that LDPE carrier bags were the lightest carrier bag alternatives that
could provide for the volume and weight holding capacity of the functional unit, while requiring
the least amount of material to be produced. Between LDPE carrier bags, the best environ-
mental performance for climate change was associated with the LDPE carrier with rigid han-
dle, since two of the simple LDPE (LDPEs) and recycled LDPE (LDPErec) would be required
to provide for the same function.
Climate change, EOL1
0,90
0,80
w
flo 0,70
0,60
nce
0,50
/ refere 0,40
eq
2 0,30
CO 0,20
kg 0,10
0,00
LDPEavg
LDPEs
LDPEh
LDPErec
PP
PPwov
PETrec
PETpol
Fossil plastic grocery carrier bags
PRO
DIS
USE
DIS EOL
EOL
Figure 12. Characterized results for the climate change impact category, incineration
end-of-life option (EOL1) expressed as kg CO2 equivalents per reference flow, for the
fossil carbon-based carrier bags LDPEavg, LDPEs, LDPEh, LDPErec, PP, PPwov,
PETrec and PETpol. PRO: production, DIS: distribution, USE: use; DIS EOL: end-of-life,
packaging; EOL: end-of-life, carrier bag; NET: net result.
5.1.6 Biopolymer bags: BP
Climate change impacts for the starch-complexed biopolymer bags (BP) are provided in Figure
13. EOL2 scored zero impacts because recycling was not considered viable for this type of
carrier bag material. Production of the carrier bag presented the highest contribution to the
impacts. The contribution analysis for the production phase shown in Table 17 shows that the
production of biopolymer is the process mostly contributing to the results. However, differently
than for fossil carbon-based grocery shopping bags, incineration provided savings due to the
considerably lower content of fossil carbon in the bag material than the previously examined
bags. Secondary reuse provided considerably lower impacts than incineration, because reuse
as a waste bin bag would avoid the production and disposal of a fossil carbon-based bag. For
the remaining impact categories, EOL3 always provided a better performance than EOL1, but
with a proportionally lower difference between the two options. Reuse of BP carrier bag as a
waste bin bag might however not provide for the same functionality of the LDPE waste bin
bag, since the survey carried out at DTU Environment has evidenced a lower resistance to
puncturing and tearing than other bags. All impact categories provided net impacts with excep-
tion of water resource use in EOL3, where the consumption of water was lower than the water
use for the waste bin bag production.
66 The Danish Environmental Protection Agency / LCA of grocery carrier bags
Table 17. Contribution analysis for the production (PRO) processes, which included the
manufacturing of the biopolymer carrier bag and the management of residues obtained
during production. The Table presents the characterized result for each impact catego-
ry, with the percent contribution given by the processes involved. Results provided for
1 biopolymer bag.
Contributing processes: energy and ancillary materials
Impact cate-
Result score
Unit
Manage-
gory
(PRO)
Biopolymer
Titanium
Electricity
Water
Ink
ment resi-
production
dioxide
dues
CC
kg CO2 eq
4.9E-02
86%
9%
5%
0%
1%
0%
OD
kg CFC11 eq
7.2E-09
87%
8%
5%
0%
0%
0%
HTC
CTUh
1.2E-09
62%
4%
34%
0%
0%
0%
HTNC
CTUh
1.9E-08
95%
4%
1%
0%
0%
0%
PM
kgPM2.5 eq
6.3E-05
89%
6%
4%
0%
1%
0%
IR
kBq U235 eq
1.7E-03
65%
34%
1%
0%
0%
0%
POF
kg NMVOC
1.8E-04
89%
5%
5%
0%
1%
0%
TA
mol H+ eq
4.1E-04
91%
5%
4%
0%
0%
0%
TE
mol N eq
7.4E-04
94%
5%
1%
0%
1%
0%
FE
kg P eq
8.3E-06
93%
6%
1%
0%
0%
0%
ME
kg N eq
1.2E-04
95%
2%
2%
0%
1%
0%
ET
CTUe
5.5E-02
79%
3%
17%
0%
0%
0%
RD fos
MJ
1.5E+00
91%
6%
3%
0%
1%
0%
RD
kg Sb eq
2.5E-06
78%
0%
26%
0%
1%
-5%
Water
L
2.1E-03
-26%
87%
41%
3%
-13%
8%
Climate change, BP
0,14
0,12
w
0,1
flo 0,08
nce 0,06
0,04
/ refere
0,02
eq
2
0
CO
kg -0,02
-0,04
-0,06
EOL1: Incineration
EOL2: Recycling
EOL3: Reuse as bin
End-of-life scenario
PRO
DIS
USE
DIS EOL
EOL
Net
Figure 13. Characterized results for the climate change impact category and the three
end-of-life options, expressed as kg CO2 equivalents per reference flow, for the starch-
complexed biopolymer carrier bag BP. PRO: production, DIS: distribution, USE: use;
DIS EOL: end-of-life, packaging; EOL: end-of-life, carrier bag; NET: net result.
The Danish Environmental Protection Agency / LCA of grocery carrier bags
67
5.1.7 Paper bags: PAP, PAPb
The environmental performance of paper carrier bags was calculated for the case of both
unbleached and bleached craft paper. The characterized results for the climate change impact
category for unbleached paper (PAP) are presented in Figure 14. Table 18 provides the con-
tribution analysis for the production phase. The majority of the impacts from the production can
be ascribed to craft paper production.
Table 18. Contribution analysis for the production (PRO) processes, which included the
manufacturing of the paper carrier bag and the management of residues obtained dur-
ing production. The Table presents the characterized result for each impact category,
with the percent contribution given by the processes involved. Results provided for 1
unbleached paper bag.
Result
Contributing processes: energy and ancillary materials
Impact
Unit
score
category
Craft paper
Management
(PRO)
Electricity
Glue
Ink
production
residues
CC
kg CO2
3.1E-02
87%
6%
2%
10%
-5%
eq
OD
kg
CFC11
4.9E-09
74%
6%
16%
4%
0%
eq
HTC
CTUh
7.1E-10
93%
3%
1%
4%
-1%
HTNC
CTUh
4.9E-08
100%
1%
0%
0%
-1%
PM
kgPM2.
8.8E-05
95%
2%
0%
3%
-1%
5 eq
IR
kBq
2.4E-03
78%
11%
11%
1%
-1%
U235 eq
kg
1.7E-04
91%
3%
3%
5%
-2%
POF
NMVOC
mol H+
2.5E-04
94%
3%
2%
5%
-5%
TA
eq
mol N
6.0E-04
93%
3%
1%
5%
-2%
TE
eq
FE
kg P eq
8.3E-06
97%
3%
0%
3%
-3%
ME
kg N eq
6.6E-05
89%
2%
1%
9%
-2%
ET
CTUe
6.9E-02
96%
1%
1%
3%
-1%
RD fos
MJ
5.9E-01
79%
7%
11%
9%
-6%
kg Sb
1.9E-05
100%
0%
0%
1%
0%
RD
eq
Water
L
1.4E-01
88%
17%
-2%
-1%
-1%
As in the case of the biopolymer bag, climate change impacts for the incineration process
provided net savings. The production process contributed proportionally less to the climate
change impacts than in the previously examined bags. Recycling of paper provided net and
higher climate change impacts than incineration, due to transportation distances, energy re-
quirements and, mostly, to the low savings associated with avoided production of craft paper.
The quality of craft paper used for paper bags was assumed to be only recyclable into paper
for cardboard production.
For all the remaining impact categories with exception of resource depletion, recycling always
performed worse than incineration, and secondary reuse always provided the absolute lowest
68 The Danish Environmental Protection Agency / LCA of grocery carrier bags
impacts (saving in the case of resource depletion), provided that the paper carrier bag can
provide the same functionality as a waste bin bag than the LDPE waste bin bag.
Impacts for the bleached paper bag (PAPb) were considerably higher due to the production
phase of the bleached paper. Overall, the same trend between disposal options was observed,
with recycling always providing larger impacts than incineration and secondary reuse. The
results of the environmental assessment indicate that utilizing unbleached paper for the paper
bag material is preferable than utilizing bleached paper.
Climate change, PAP
0,12
0,1
w 0,08
flo
0,06
nce 0,04
0,02
/ refere
0
eq
2 -0,02
CO -0,04
kg -0,06
-0,08
EOL1: Incineration
EOL2: Recycling
EOL3: Reuse as bin
End-of-life scenario
PRO
DIS
USE
DIS EOL
EOL
Net
Figure 14. Characterized results for the climate change impact category and the three
end-of-life options, expressed as kg CO2 equivalents per reference flow, for the un-
bleached paper carrier bag PAP. PRO: production, DIS: distribution, USE: use; DIS
EOL: end-of-life, packaging; EOL: end-of-life, carrier bag; NET: net result.
5.1.8 Cotton and composite bags: COTorg, COT, COM
The characterized results for the cotton bag options (COTorg, COT) and the carrier bag with
composite materials (COM) are presented in the same paragraph due to their shared charac-
teristics. As it is illustrated for the climate change results for organic cotton in Figure 15, these
types of carrier bags presented the highest observed impacts related to their production. EOL2
scored zero in Figure 15 since recycling was not considered viable for this type of carrier bag.
The same was assumed for COT and COM.
In the case of organic cotton (COTorg), production contributed to 99 % of the impact, 98 %
and 96% for COT and COM scenarios, respectively. The contribution analysis for the produc-
tion phase of these bags is provided in Tables 19 – 21. The high environmental cost of the
cotton production can be ascribed to the energy and material required, which is responsible for
80 % of the climate change impacts. In general, the results showed very little difference be-
tween EOL1 and EOL3, due to the comparatively small weight of the avoided waste bin bag in
comparison to the mass (and resources required for its production) of the cotton bag. The
same behaviour was observed for all impact categories, as well as for COT and COM, even if
with a lower magnitude in the impacts.
The environmental impacts connected to the production of the organic cotton bag (COTorg)
were considerably higher than those of the conventional cotton bag (COT). This is due to the
fact that organic cotton production does not involve the use of synthetic chemicals such as
The Danish Environmental Protection Agency / LCA of grocery carrier bags
69
fertilizers and pesticides, which lowers the yield of the cultivation. Eventually, more resources
and land are required to produce the same amount of cotton than in conventional cotton culti-
vation processes.
Table 19. Contribution analysis for the production (PRO) processes, which included the
manufacturing of the organic cotton carrier bag and the management of residues ob-
tained during production. The Table presents the characterized result for each impact
category, with the percent contribution given by the processes involved. Results pro-
vided for 1 organic cotton bag.
Contributing processes: energy and ancillary materials
Result
Impact catego- Unit
score
Cotton
ry
Electrici-
Management
(PRO)
produc-
Heat
N fertiliser
ty
residues
tion
CC
kg CO2 eq
5.4E+00
99%
0%
1%
0%
0%
OD
kg CFC11 eq
1.4E-05
100%
0%
0%
0%
0%
HTC
CTUh
2.4E-07
100%
0%
0%
0%
0%
HTNC
CTUh
8.7E-07
101%
0%
-1%
0%
0%
PM
kgPM2.5 eq
5.5E-03
100%
0%
0%
0%
0%
IR
kBq U235 eq
1.9E-01
100%
0%
0%
0%
0%
POF
kg NMVOC
1.3E-02
100%
0%
0%
0%
0%
TA
mol H+ eq
2.9E-02
100%
0%
0%
0%
0%
TE
mol N eq
7.0E-02
100%
0%
0%
0%
0%
FE
kg P eq
6.8E-04
100%
0%
0%
0%
0%
ME
kg N eq
4.9E-03
100%
0%
0%
0%
0%
ET
CTUe
1.6E+01
100%
0%
0%
0%
0%
RD fos
MJ
1.0E+02
99%
0%
1%
0%
0%
RD
kg Sb eq
2.2E-04
100%
0%
0%
0%
0%
Water
L
3.8E+01
100%
0%
0%
0%
0%
Climate change, COTorg
12
10
w
flo
8
nce
6
/ refere
4
eq
2
2
CO
kg
0
-2
EOL1: Incineration
EOL2: Recycling
EOL3: Reuse as bin
End-of-life scenario
PRO
DIS
USE
DIS EOL
EOL
Net
Figure 15. Characterized results for the climate change impact category and the three
end-of-life options, expressed as kg CO2 equivalents per reference flow, for the organic
cotton carrier bag COTORG. PRO: production, DIS: distribution, USE: use; DIS EOL:
end-of-life, packaging; EOL: end-of-life, carrier bag; NET: net result.
70 The Danish Environmental Protection Agency / LCA of grocery carrier bags
Table 20. Contribution analysis for the production (PRO) processes, which included the
manufacturing of the conventional cotton carrier bag and the management of residues
obtained during production. The Table presents the characterized result for each im-
pact category, with the percent contribution given by the processes involved. Results
provided for 1 conventional cotton bag.
Contributing processes: energy and ancillary
Result
materials
Impact category
Unit
score
(PRO)
Cotton
Management
Electricity
Heat
production
residues
CC
kg CO2 eq
3.9E+00
99%
0%
1%
0%
OD
kg CFC11
1.0E-05
100%
0%
0%
0%
eq
HTC
CTUh
1.7E-07
100%
0%
0%
0%
HTNC
CTUh
6.2E-07
101%
0%
-1%
0%
PM
kgPM2.5
3.9E-03
100%
0%
0%
0%
eq
IR
kBq U235
1.3E-01
101%
0%
-1%
0%
eq
POF
kg NMVOC
8.9E-03
100%
0%
0%
0%
TA
mol H+ eq
2.1E-02
100%
0%
0%
0%
TE
mol N eq
5.0E-02
100%
0%
0%
0%
FE
kg P eq
4.8E-04
100%
0%
0%
0%
ME
kg N eq
3.5E-03
100%
0%
0%
0%
ET
CTUe
1.1E+01
100%
0%
0%
0%
RD fos
MJ
7.2E+01
99%
0%
1%
0%
RD
kg Sb eq
1.6E-04
100%
0%
0%
0%
Water
L
2.7E-01
100%
0%
0%
0%
Table 21. Contribution analysis for the production (PRO) processes, which included the
manufacturing of the composite carrier bag and the management of residues obtained
during production. The Table presents the characterized result for each impact catego-
ry, with the percent contribution given by the processes involved. Results provided for
1 composite bag.
Contributing processes: energy and ancillary mate-
rials
Result
Impact cate-
Man-
Unit
score
gory
Jute
Cotton
agement
(PRO)
PP pro-
produc-
produc-
Electricity
Heat
duction
residues
tion
tion
CC
kg CO2
1.7E+00
68%
27%
3%
0%
2%
0%
eq
OD
kg
CFC11
1.2E-06
3%
97%
0%
0%
0%
0%
eq
HTC
CTUh
4.3E-08
52%
48%
1%
0%
0%
0%
HTNC
CTUh
-1.2E-07
158%
-62%
0%
0%
4%
0%
PM
kgPM2.
3.0E-03
84%
16%
1%
0%
0%
0%
5 eq
The Danish Environmental Protection Agency / LCA of grocery carrier bags
71
Table 21. (continued) Contribution analysis for the production (PRO) processes, which
included the manufacturing of the composite carrier bag and the management of resi-
dues obtained during production. The Table presents the characterized result for each
impact category, with the percent contribution given by the processes involved. Results
provided for 1 composite bag.
Contributing processes: energy and ancillary materials
Result
Man-
Impact cate-
Unit
score
Jute
Cotton
agement
gory
PP pro-
(PRO)
produc-
produc-
Electricity
Heat
duction
residues
tion
tion
IR
kBq
U235
3.6E-02
59%
44%
0%
0%
-3%
0%
eq
POF
kg
NMVO
5.0E-03
74%
21%
5%
0%
0%
0%
C
TA
mol H+
1.1E-02
77%
21%
2%
0%
0%
0%
eq
TE
mol N
3.5E-02
82%
17%
1%
0%
0%
0%
eq
FE
kg P eq 2.4E-04
76%
24%
1%
0%
-1%
0%
ME
kg N eq 2.6E-03
82%
16%
2%
0%
0%
0%
ET
CTUe
4.2E+00
67%
33%
1%
0%
0%
0%
RD fos
MJ
3.0E+01
62%
29%
7%
0%
3%
0%
RD
kg Sb
3.1E-05
39%
61%
0%
0%
0%
0%
eq
Water
L
5.1E+00
39%
62%
0%
0%
-2%
0%
5.2
Overview
The aim of the following Figures 16 and 17 is to provide a comparison between the climate
change results for the EOL1 disposal scenarios of all carrier bag alternatives. Cotton and
composite bags were left out of Figure 16 in order to visualize the results for the remaining
carrier bags, which would be out scaled otherwise, as shown in the following Figure 17.
The lowest climate change impacts were provided by LDPE carrier bags with rigid handle,
paper bags and biopolymer bags, with slight differences in results. Heavier PP, PET, polyester
and bleached paper carrier bags provided higher impact scores. The highest absolute impacts
were scored by organic cotton bags, mostly for the environmental cost of the organic cotton
production.
72 The Danish Environmental Protection Agency / LCA of grocery carrier bags
Climate change, EOL1
0,9
0,8
w 0,7
flo 0,6
nce 0,5
0,4
/ refere 0,3
eq
2 0,2
CO 0,1
kg
0,0
-0,1
Grocery carrier bags
PRO
DIS
USE
DIS EOL
EOL
Figure 16. Characterized results for the climate change impact category, incineration
end-of-life option (EOL1) expressed as kg CO2 equivalents per reference flow, for the
carrier bags LDPEavg, LDPEs, LDPEh, LDPErec, PP, PPwov, PETrec, PETpol, BP, PAP,
PAPb. PRO: production, DIS: distribution, USE: use; DIS EOL: end-of-life, packaging;
EOL: end-of-life, carrier bag; NET: net result.
Climate change, EOL1
12
10
w
flo
8
nce
6
/ refere
4
eq
2
2
CO
kg
0
-2
Grocery carrier bags
PRO
DIS
USE
DIS EOL
EOL
Figure 17. Characterized results for the climate change impact category, incineration
end-of-life option (EOL1) expressed as kg CO2 equivalents per reference flow, for the
carrier bags LDPEavg, LDPEs, LDPEh, LDPErec, PP, PPwov, PETrec, PETpol, BP, PAP,
PAPb, COM, COTorg, COT. PRO: production, DIS: distribution, USE: use; DIS EOL: end-
of-life, packaging; EOL: end-of-life, carrier bag; NET: net result
.
The Danish Environmental Protection Agency / LCA of grocery carrier bags
73
6. Discussion
6.1
Identification of the best disposal option for each carrier
bag
Table 22 indicates, for each of the carrier bags in the rows, the disposal option providing the
lowest environmental impacts, for each of the impact categories in the columns. In order to
facilitate reading, incineration (EOL1) was associated with red colour, recycling (EOL2) was
associated with light blue and secondary reuse as waste bin bag (EOL3) was assigned light
green colour.
Overall, EOL3 is the disposal option that provided the lowest environmental impacts for most
of the impact categories and carrier bag options. As observed in the contribution analysis for
each of the carrier bags, this is due to the fact that reuse as waste bin bag before incineration
allowed avoiding production and disposal of an LDPE carrier bag. The difference between
EOL1 results and EOL3 results was larger (and EOL3 comparatively more beneficial) when
the weight of the carrier bag was comparable to the weight of the LDPE waste bin bag, as in
the case of LDPE carrier bags (LDPEs, LDPEh, LDPErec), biopolymer bags (BP) and paper
bags (PAP, PAPb). For heavier carrier bags, and especially for the cotton (COTorg, COT) and
the composite (COM) bags, the difference between EOL1 and EOL3 result was smaller. EOL3
thus resulted being the overall best disposal option, provided that the reused carrier bag can
fulfil the waste bin bag function.
The results shown in the table also highlight that for heavier plastic carrier bags (PP, PPwov,
PETrec) recycling (EOL2) resulted in being the most favourable disposal option in some im-
pact categories, especially resource depletion and climate change. Therefore, collecting the
waste bin bags within the recyclables waste stream might be a viable option for this type of
carrier bags. The results for the ozone depletion, human toxicity, non-cancer effects and
freshwater eutrophication impact categories showed a consistent preference for the EOL1
disposal scenario, due to the avoided environmental impacts connected to electricity and heat
production that are avoided recovering energy within the incineration process.
74 The Danish Environmental Protection Agency / LCA of grocery carrier bags
Table 22. Disposal options providing the lowest environmental impacts for each of the
carrier bags in the rows and each of the impact categories in the columns. The colour
scale refers to the disposal option: red was assigned to incineration (EOL1), blue to
recycling (EOL2), and green to secondary reuse as a waste bin bag (EOL3). Please refer
to the abbreviations for the acronyms for carrier bags scenarios and impact categories.
Sce-
HT
RD
Wa-
nario
CC
OD
HTC
PM
IR
POF
TA
TE
FE
ME
ET
RD
NC
fos
ter
name
LDPE
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
avg
3
1
3
1
3
3
3
3
3
1
3
3
3
3
3
LDPE
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
s
3
1
3
1
3
3
3
3
3
1
3
3
3
3
1
LDPE
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
h
3
1
3
1
3
3
3
3
3
1
3
3
3
3
3
LDPE
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
rec
3
1
3
1
3
3
3
3
3
1
3
3
3
3
3
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
PP
2
1
3
1
3
3
3
3
3
1
3
3
2
3
3
PPwo
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
v
2
1
3
1
3
3
3
3
3
1
3
3
2
3
3
PETr
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
ec
2
1
2
1
3
3
3
3
3
2
3
3
3
2
2
PET-
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
pol
3
1
2
1
3
3
3
3
3
2
3
3
3
2
2
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
BP
3
1
3
1
3
3
3
3
3
1
3
3
3
3
3
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
PAP
3
1
3
1
3
3
3
3
3
1
3
3
3
3
3
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
PAPb
3
1
3
1
3
3
3
3
3
1
3
3
3
3
3
CO-
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
Torg
3
1
3
1
3
3
3
3
3
1
3
3
3
3
3
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
COT
3
1
3
1
3
3
3
3
3
1
3
3
3
3
3
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
COM
3
1
3
1
3
3
3
3
3
1
3
3
3
3
3
The Danish Environmental Protection Agency / LCA of grocery carrier bags
75
6.2
Which carrier bag provides the lowest environmental
impact to fulfil the function?
Table 23 provides the hierarchy of the characterized results between all carrier bags and dis-
posal options. Each column provides the carrier bag and disposal option results, ordered from
lowest impact to highest impact, for each of the impact categories indicated in the columns.
The colour pattern was assigned in order to distinguish carrier bag types and to aid readability.
Dark blue was assigned to LDPE, lighter blue to PP bags and so on.
For climate change, the carrier bags scoring the lowest climate change impacts were un-
bleached paper, biopolymer and LDPE carrier bags. Paper and biopolymer bags provided the
lowest scores when reused as a waste bin bag. Whether it was reused or incinerated, paper
provided a slightly better climate change performance than LDPE carrier bags. LDPE carrier
bags provided a preferable performance than other carrier bags for climate change when they
were reused, secondarily when they were recycled and thirdly incinerated. Heavier carrier
bags provided the highest climate change impacts, with polyester, PP, recycled PET, compo-
site and cotton providing increasingly higher climate change impacts. As observed in the con-
tribution analysis, a similar pattern could be identified for the impact categories of human tox-
icity, cancer effects, and resource depletion, fossil. The lowest impacts for the remaining im-
pact categories were provided by LDPE carrier bags. LDPEavg results represent an average
LDPE carrier bag; between LDPE carrier bags LDPEh obtained the lowest impacts in most
impact categories. The highest impacts in all impact categories were provided by organic cot-
ton.
Overall, light carrier bags such as LDPE, paper and biopolymer were the carrier bag alterna-
tives that provided the lowest environmental impacts in order to provide for the function ex-
pressed in the functional unit of this LCA. Heavier multiple-use carrier bags such as composite
and cotton bags obtain the highest environmental impacts across all impact categories. For
this reason, it is useful to determine the number of necessary reuse times to lower the envi-
ronmental impacts related to their production to values comparable to lighter carrier bags.
76 The Danish Environmental Protection Agency / LCA of grocery carrier bags
Table 23. Hierarchy of the results obtained by each carrier bag alternative for each of
the disposal options, subdivided by impact categories. The cells in the table represent
the result scores, sorted from lowest (lowest environmental impacts per impact catego-
ry, top) to highest (highest environmental impacts per impact category, bottom). The
colour scale was assigned to facilitate distinguishing between carrier bag types.
HTN
RD
Wa-
CC
OD
HTC
PM
IR
POF
TA
TE
FE
ME
ET
RD
C
fos
ter
LDPE
LDPE
LDPE
LDPE
LDPE
LDPE
LDPE
PAP
PAP
COM
LDPEs
PPwov
PAP
PPwov LDPEh
avg
avg
avg
avg
avg
rec
avg
EOL3
EOL3
EOL1
EOL3
EOL3
EOL3
EOL3
EOL3
EOL1
EOL3
EOL3
EOL2
EOL2
EOL1
EOL3
LDPE
LDPE
LDPE
LDPE
LDPE
BP
LDPEh
PP
LDPEh LDPEh
LDPEh LDPEh LDPEs
LDPEh
BP
avg
rec
avg
avg
avg
EOL3
EOL1
EOL1
EOL3
EOL3
EOL2
EOL2
EOL1
EOL3
EOL3
EOL3
EOL3
EOL3
EOL3
EOL3
LDPE
LDPE
LDPE
PAP
PAPb PPwov LDPEs LDPEs LDPEh LDPEs LDPEs LDPEh LDPEh
PAP
LDPEs
avg
avg
avg
EOL1
EOL3
EOL1
EOL3
EOL3
EOL3
EOL2
EOL2
EOL1
EOL3
EOL1
EOL3
EOL3
EOL1
EOL1
LDPE
LDPE
LDPE
LDPE
LDPE
LDPE
LDPE
LDPE
LDPE
LDPE
LDPEh
LDPEs
PP
LDPEs
LDPEh
avg
avg
rec
avg
avg
avg
rec
avg
avg
avg
EOL3
EOL3
EOL3
EOL3
EOL3
EOL3
EOL2
EOL1
EOL1
EOL1
EOL3
EOL2
EOL1
EOL2
EOL3
LDPE
LDPE
LDPE
LDPEs
LDPEs LDPEh LDPEh PAPb
PAPb LDPEh
LDPEs LDPEh LDPEh
PP
BP
avg
avg
avg
EOL1
EOL1
EOL1
EOL1
EOL3
EOL2
EOL1
EOL3
EOL1
EOL3
EOL3
EOL1
EOL2
EOL1
EOL1
LDPE
LDPE
LDPE
LDPE
LDPE
BP
LDPEs LDPEh PETrec LDPEs LDPEs PPwov PPwov
LDPEs PPwov
rec
rec
rec
avg
rec
EOL1
EOL3
EOL3
EOL1
EOL1
EOL1
EOL3
EOL2
EOL3
EOL1
EOL2
EOL3
EOL3
EOL2
EOL3
LDPE
LDPE
LDPE
LDPE
LDPE
LDPE
LDPEh
PAP
LDPEh
PP
LDPEs LDPEh
BP
PAPb LDPEh
rec
rec
rec
avg
avg
avg
EOL3
EOL1
EOL1
EOL3
EOL1
EOL3
EOL3
EOL3
EOL2
EOL1
EOL3
EOL3
EOL3
EOL2
EOL1
LDPE-
LDPE
LDPE
LDPE
LDPE
LDPE
LDPEs
LDPEh
PETpol PETpol
PAP
PAPb
BP
LDPEh LDPEh
rec
avg
avg
rec
avg
avg
EOL3
EOL2
EOL3
EOL2
EOL2
EOL3
EOL3
EOL1
EOL1
EOL3
EOL1
EOL2
EOL1
EOL3
EOL1
LDPE
LDPE
LDPE
LDPE
LDPE
LDPEh
PAPb PETpol
BP
PAP
PETpol
PETpol LDPEs
BP
LDPEs
avg
rec
avg
avg
rec
EOL2
EOL1
EOL1
EOL3
EOL2
EOL2
EOL3
EOL1
EOL3
EOL3
EOL2
EOL1
EOL2
EOL2
EOL1
PAP
LDPEh LDPEh PAPb LDPEh LDPEh
PAP
PP
PAPb LDPEh PETrec LDPEh LDPEs
PP
LDPEs
EOL2
EOL2
EOL1
EOL1
EOL2
EOL2
EOL3
EOL2
EOL2
EOL2
EOL3
EOL2
EOL2
EOL1
EOL1
LDPE
LDPE
LDPE
LDPE
LDPE
LDPEs LDPEs
BP
LDPEs LDPEs PETrec LDPEh
LDPEs
LDPEh LDPEh
avg
rec
avg
rec
avg
EOL2
EOL3
EOL1
EOL2
EOL2
EOL3
EOL3
EOL2
EOL1
EOL2
EOL1
EOL1
EOL1
EOL3
EOL2
LDPE
LDPE
LDPE
LDPE
LDPE
PAPb
PAP
PAP
PAPb
LDPEs PPwov
LDPEh PAPb
PAP
LDPEs
rec
rec
avg
rec
rec
EOL3
EOL2
EOL1
EOL3
EOL3
EOL2
EOL1
EOL1
EOL2
EOL1
EOL2
EOL2
EOL1
EOL2
EOL2
LDPE
LDPE
LDPEs
PAP
PAPb
COT
PPwov
BP
LDPEh
PP
PAPb
COM
BP
LDPEs LDPEh
rec
rec
EOL2
EOL1
EOL2
EOL1
EOL3
EOL3
EOL1
EOL2
EOL1
EOL3
EOL1
EOL2
EOL2
EOL3
EOL3
COT
LDPE
LDPE
LDPEh
PAP
LDPEs
PETpol
COM PETrec PETrec PAPb LDPEs LDPEs LDPEs
LDPEs
org
rec
rec
EOL1
EOL3
EOL2
EOL3
EOL3
EOL2
EOL2
EOL3
EOL1
EOL2
EOL1
EOL2
EOL1
EOL2
EOL3
LDPE
LDPE
BP
PPwov
PPwov PAPb LDPEs PETpol PETpol PAPb
PAP
PETpol PAPb PPwov PAPb
rec
avg
EOL1
EOL3
EOL1
EOL1
EOL1
EOL3
EOL1
EOL2
EOL3
EOL3
EOL3
EOL2
EOL3
EOL3
EOL3
LDPE
LDPE
LDPE
LDPE
LDPE
LDPEs
BP
BP
LDPEh PETpol
BP
PETpol
PPwov PPwov
PAPb
avg
rec
rec
rec
rec
EOL1
EOL3
EOL3
EOL3
EOL1
EOL1
EOL1
EOL1
EOL1
EOL1
EOL1
EOL1
EOL1
EOL2
EOL1
LDPE
PAP
LDPEs LDPEs
PP
PETpol
BP
PAP
PP
PPwov PETpol
PAP
BP
PP
PAP
rec
EOL2
EOL1
EOL3
EOL3
EOL3
EOL1
EOL3
EOL1
EOL3
EOL1
EOL3
EOL1
EOL2
EOL3
EOL2
LDPE
PAPb PETpol PETpol
BP
BP
PETpol
PAP
LDPEh
PAP
PETpol
PAP
PETpol PETpol
PAP
rec
EOL1
EOL1
EOL2
EOL3
EOL3
EOL1
EOL1
EOL1
EOL1
EOL2
EOL1
EOL1
EOL3
EOL1
EOL2
LDPE
LDPE
PETpol PETpol PETpol
PAP
PP
PETpol
PPwov
BP
PP
PPwov PAPb
BP
PETpol
rec
rec
EOL3
EOL3
EOL3
EOL3
EOL1
EOL2
EOL3
EOL1
EOL1
EOL1
EOL2
EOL3
EOL2
EOL1
EOL1
The Danish Environmental Protection Agency / LCA of grocery carrier bags
77
Table 23. (continued) Hierarchy of the results obtained by each carrier bag alternative
for each of the disposal options, subdivided by impact categories. The cells in the table
represent the result scores, sorted from lowest (lowest environmental impacts per im-
pact category, top) to highest (highest environmental impacts per impact category,
bottom). The colour scale was assigned to facilitate distinguishing between carrier bag
types.
CC
OD
HTC
HTNC
PM
IR
POF
TA
TE
FE
ME
ET
RD fos
RD
Water
LDPE
PETpol PAPb PPwov PETpol PETpol PAPb
PAPb
PAPb
PAPb
PP
COT
PETpol PAPb PETpol
rec
EOL2
EOL1
EOL1
EOL3
EOL2
EOL2
EOL1
EOL3
EOL1
EOL3
EOL3
EOL2
EOL3
EOL3
EOL2
LDPE
PAPb
PAPb
BP
BP
PAP
COT
LDPEs PETrec PETpol PAPb PPwov PAPb
PAPb PETpol
rec
EOL2
EOL3
EOL1
EOL1
EOL3
EOL3
EOL1
EOL1
EOL1
EOL1
EOL3
EOL1
EOL2
EOL1
EOL3
LDPE
LDPE
PETpol
PP
PAPb
PAP
PAP
PP
COM PETpol
PP
PAP
PETpol PAPb PPwov
rec
avg
EOL2
EOL3
EOL3
EOL3
EOL1
EOL3
EOL1
EOL3
EOL1
EOL1
EOL1
EOL1
EOL3
EOL1
EOL2
LDPE
LDPE
PETpol PAPb
PAP
PPwov LDPEh PETrec
COT
PPwov PETrec PPwov PAPb
BP
PPwov
rec
avg
EOL1
EOL2
EOL1
EOL3
EOL2
EOL3
EOL1
EOL2
EOL1
EOL1
EOL2
EOL1
EOL1
EOL3
EOL2
LDPE
PPwov PPwov PETpol LDPEh PPwov PPwov LDPEs
BP
BP
BP
PP
PPwov PETpol
PP
avg
EOL2
EOL1
EOL1
EOL2
EOL2
EOL1
EOL2
EOL3
EOL1
EOL1
EOL3
EOL2
EOL2
EOL3
EOL3
LDPE
COT
PPwov PPwov
PP
PPwov
PP
PAP
PPwov
LDPEh
BP
PAP
PPwov PETpol
PP
rec
org
EOL3
EOL3
EOL1
EOL3
EOL2
EOL2
EOL1
EOL3
EOL3
EOL2
EOL3
EOL3
EOL1
EOL1
EOL3
LDPE
PP
PP
LDPEs
PAP
PP
PP
PETpol LDPEs
PAP
COM
PP
PP
PETpol PPwov
rec
EOL2
EOL1
EOL2
EOL2
EOL3
EOL1
EOL1
EOL3
EOL1
EOL1
EOL1
EOL2
EOL1
EOL2
EOL2
LDPE
PPwov
PP
PETrec PETrec
PP
PETrec
PAP
PAPb
PAP
COT
PETpol PPwov PETrec
PP
rec
EOL1
EOL3
EOL3
EOL3
EOL1
EOL1
EOL1
EOL3
EOL3
EOL1
EOL2
EOL1
EOL2
EOL2
EOL1
LDPE
COT
PP
PETrec PPwov
PP
PETrec PPwov
PPwov
BP
PAP
PPwov
PP
PETrec PETrec
rec
org
EOL3
EOL1
EOL2
EOL3
EOL1
EOL2
EOL1
EOL3
EOL2
EOL2
EOL3
EOL3
EOL2
EOL2
EOL1
LDPE
LDPE
PP
PETrec
PP
PAPb PETrec
PAP
PP
PP
PAP
PP
PP
PETrec PETrec
rec
rec
EOL1
EOL3
EOL2
EOL3
EOL3
EOL2
EOL1
EOL2
EOL2
EOL2
EOL1
EOL1
EOL3
EOL2
EOL3
COT
COT
LDPE
PETrec PPwov PETrec PAPb
PAPb PETrec
PAPb
PETrec
PETrec PETrec COM PETrec
org
org
avg
EOL2
EOL2
EOL2
EOL2
EOL1
EOL1
EOL1
EOL2
EOL3
EOL3
EOL3
EOL1
EOL3
EOL1
EOL2
PETrec
PP
PETrec PETpol PETrec
PP
PETpol
BP
PETpol PETrec LDPEh PETrec PETrec COM
PAPb
EOL3
EOL2
EOL3
EOL2
EOL2
EOL2
EOL2
EOL1
EOL3
EOL1
EOL2
EOL1
EOL2
EOL1
EOL2
PETrec PETrec PETrec COM
PAPb PETrec PAPb PETrec
PAP
PETrec LDPEs PETrec PETrec
PAP
PAP
EOL1
EOL2
EOL1
EOL3
EOL2
EOL2
EOL2
EOL1
EOL3
EOL3
EOL2
EOL2
EOL1
EOL3
EOL2
COM
COM
COM
PAP
COM
COM
PPwov
COM
PPwov
COM
PAPb
COM
COM
PAP
COM
EOL3
EOL1
EOL3
EOL2
EOL3
EOL3
EOL2
EOL3
EOL3
EOL1
EOL2
EOL3
EOL3
EOL2
EOL3
LDPE
COM
COM
COM
PPwov
COM
COM
PP
COT
PP
COM
COM
COM
PAP
COM
rec
EOL1
EOL3
EOL1
EOL2
EOL1
EOL1
EOL2
EOL3
EOL3
EOL3
EOL1
EOL1
EOL1
EOL1
EOL2
COT
COT
COT
COT
PP
COT
COT
PETrec
PETrec
COT
PETpol
COT
COT
COT
COT
org
EOL3
EOL1
EOL3
EOL2
EOL3
EOL3
EOL2
EOL3
EOL1
EOL2
EOL3
EOL3
EOL3
EOL3
EOL3
COT
COT
COT
COT
COT
COT
COM
COM
COM
COT
PPwov
COT
COT
COT
COT
EOL1
EOL3
EOL1
EOL3
EOL1
EOL1
EOL1
EOL1
EOL3
EOL3
EOL2
EOL1
EOL1
EOL1
EOL1
COT
COT
COT
COT
COT
COT
COT
COT
PETrec COTorg COTorg COT
COT
COT
PP
org
org
org
org
org
org
org
org
EOL2
EOL3
EOL3
EOL1
EOL1
EOL3
EOL2
EOL3
EOL1
EOL3
EOL1
EOL3
EOL3
EOL3
EOL3
COT
COT
COT
COT
COT
COT
COT
COT
COT
COT
COT
COT
COT
COT
PETrec
org
org
org
org
org
org
org
org
org
org
org
org
org
org
EOL2
EOL1
EOL3
EOL1
EOL3
EOL1
EOL1
EOL1
EOL1
EOL3
EOL3
EOL1
EOL1
EOL1
EOL1
78 The Danish Environmental Protection Agency / LCA of grocery carrier bags
6.3
How many times should a carrier bag be reused?
This Section provides the calculated number of primary reuse times for each carrier bag type,
as indicated in Section 3. The number of reuse times provided in Table 24 indicates how many
times the carrier bag alternatives in the rows should be reused in order to provide the same
environmental performance of the reference LDPE carrier bag (LDPEavg), associated with
EOL3 as a disposal option. The number of reuse times for each carrier bag alternative was
calculated for each disposal option: EOL1, EOL2, and EOL3
The results are provided for the climate change impact category, as well as across impact
categories. The result score across all impact categories was obtained by calculating the
number of primary reuse times necessary for each impact category, and identifying the maxi-
mum score across all impact categories. This maximum score represents the maximum num-
ber of reuse times that would be required to obtain the same environmental performance of
the reference LDPE carrier bag considering all impact categories. Results for each impact
category, minimum-maximum ranges between number of reuse times and average number of
reuse times are provided in Appendix C.
Zero values are shown where LDPEavg, EOL3 is compared to itself. Values lower than zero
corresponds to carrier bag options that already provide a better environmental performance
than the carrier bag option to which they are compared. Values higher than zero indicate how
many times the corresponding carrier bags in the rows should be reused before being dis-
posed of (with its corresponding end-of-life scenario) in order to provide the environmental
performance of LDPEavg, EOL3.
Table 24. Calculated number of primary reuse times for the carrier bags in the rows,
associated with the disposal options in the columns, necessary to provide the same
environmental performance of the average LDPE carrier bag, reused as a waste bin bag
before incineration (EOL3). Results are provided for the climate change impact category
and across impact categories. Yellow cells highlight the most preferable disposal op-
tion. Results for COTorg, COT and COM have been rounded.
LDPEavg, EOL3
Climate change
All impact categories
EOL1
EOL2
EOL3
EOL1
EOL2
EOL3
LDPEavg
0.5
0.1
0.0
1.2
5.0
0.0
LDPEs
1.3
0.7
0.3
2.3
7.8
0.5
LDPEh
0.9
0.4
0.3
1.7
6.1
0.3
LDPErec
2.2
1.4
1.2
3.4
11.7
1.6
PP
8.0
6.0
7.3
38
52
37
PPwov
6.8
5.0
5.9
33
45
32
PETrec
9.6
8.2
8.6
95
84
96
PETpol
2.6
1.9
1.9
35
28
35
BP
0.2
-
-0.8
41
-
42
PAP
-0.2
0.5
-1.3
42
77
43
PAPB
1.5
2.2
0.6
30
72
43
COTorg
150
-
149
20000
-
20000
COT
53
-
52
7100
-
7100
COM
23
-
23
870
-
870
The Danish Environmental Protection Agency / LCA of grocery carrier bags
79
For climate change, the LDPE carrier bag alternatives LDPEs, LDPEh, LDPErec provided a
comparable performance to the average LDPE carrier bag, with lower number of reuse times
obtained for the EOL3 disposal options. The results indicate that LDPEh is the carrier bag
providing the best climate change performance, since this carrier bag type is associated to the
lowest number of reuse times for all end-of-life options. In general, LDPE carrier bags should
be reused at least one time before being used as a waste bin bag.
Heavier fossil-carbon based bags provided the lowest number of reuse times for the EOL2
disposal options. The results indicate that these types of carrier bags should be reused 5 – 10
times before being disposed, with exception for the polyester bag, whose preferable disposal
option was EOL3 and which scored a needed reuse of 2 times.
Unbleached paper and biopolymer bags scored negative values, indicating that the climate
change impact associated with these bags is already lower than the climate change impact
associated with the average LDPE carrier bag. The negative value indicates that for these
types of carrier bags, reuse before disposal would not even be necessary to provide a better
climate change result. Moreover, the results indicate that paper and biopolymer are a better
option than LDPE with respect to climate change impacts. Bleached paper should be reused
for 2 times, due to the higher environmental costs related to its production.
The absolute highest number of reuse times for the climate change impact category was ob-
tained for composite and cotton carrier bags. In particular, conventional cotton carrier bags
should be reused at least 50 times before being disposed of; organic cotton carrier bags
should be reused 150 times based on their environmental production cost. This calculated
number of primary reuse times for cotton bags complies with results of previous studies. For
example, Edwards and Fry (2011) calculated a number of around 130 reuse times required for
cotton carrier bags to provide similar climate change impacts in comparison to HDPE carrier
bags, which were chosen as reference in that study.
When all impact categories were taken into consideration, Table 24 provides the highest num-
ber of reuse times across all the considered environmental indicators. The results for each
impact category are available in Appendix C. LDPE carrier bags provided the absolute best
environmental performance. With reuse as waste bin bag as the considered as disposal op-
tion, it suffices to reuse LDPE carrier bags one time before reusing them as waste bin bag.
Heavier PP carrier bags and polyester bags would need to be reused 30 – 40 times. Paper
and biopolymer carrier bags should be reused up to 40 times in order to provide for a similar
environmental performance, mostly due to the impacts in the freshwater eutrophication impact
category. In a number of categories bleached paper was found to have a lower impact than
unbleached paper. The reason for this difference was found to be due to a lower data quality
for bleached paper that did not include as detailed a dataset. Since the difference in produc-
tion of bleached versus unbleached kraft paper is only the bleaching step, we did not find it
realistic that unbleached paper could have higher impacts. For these categories we therefore
assume that the bleached number must be the same or higher than the unbleached number.
In order to provide a comparable performance to LDPE in all impact categories, the number of
reuse times for cotton and composite bags increased to thousands of times.
For LDPE carrier bags, the number of reuse times was rather uniform across impact catego-
ries. For PP and PET bags, some impact categories presented higher reuse times than others,
especially ozone depletion, terrestrial eutrophication, freshwater eutrophication and water use.
For these indicators, the results of PP and PET carrier bags were considerably higher (such as
one order of magnitude) than the results obtained by the LDPE carrier bag. This occurred
because for PP and PET carrier bags the higher environmental cost of production is not com-
pensated by the energy or material recovered – while for the lighter LDPE carrier bag the
environmental production costs are lower. The same observations can be made for BP and
80 The Danish Environmental Protection Agency / LCA of grocery carrier bags
PAP carrier bags, which obtained considerably higher numbers of reuse times for terrestrial
and freshwater eutrophication impact categories. Lastly, the high number of reuse times
scored by cotton and composite bags is due only to the ozone depletion impact category,
where cotton production provides considerably large impacts.
It is important to remark that, even if LDPE scored a low (to zero) number of reuse times, this
is due to the fact that it was compared to a reference LDPE carrier bag. Reuse of each type of
carrier bags, even LDPE, should be carried out as many times as possible before disposal. In
the case of heavier carrier bags, customers of Danish supermarkets should be informed on the
optimal number of reuse times of multiple-use carrier bags offered as alternatives for the
LDPE carrier.
Finally, it is important to consider that the avoided reference bag can in practice also be re-
used, and if this is the case then the reuse number calculated above would proportionally be
as many times higher as it was reused. The resulting reuse numbers calculated in this study
should therefore be seen as a minimum reuse number that could be higher.
All results presented above are linked to specific types of bags used on the market today. If
the bags were designed differently with larger volume to carrying weight ratio, from recycled
material instead of primary material where only one type material is presented, or some other
type of improvement the results would come out better than the standard version of the same
bag.
This study focused on identifying the number of reuse times based on the environmental per-
formance of the carrier bags, rather than considering the actual realistic lifetime for different
bag types considering their material type, production, and functionality. The results obtained
on the minimum number of reuse times are intended to raise the discussion among the stake-
holders on the effective expected lifetime of each carrier bag. While the calculated number of
reuse times might be compliant with the functional lifetime of PP, PET and polyester carrier
bags, it might surpass the lifetime of bleached paper, composite and cotton carriers, especially
considering all environmental indicators.
6.4
Influence on data and assumptions on the results
Data availability was found to be rather low. The number of reviewed LCA reports and data
available in the literature was limited. In particular, data on the manufacturing part for the car-
rier bags (energy and ancillary materials requirements) was rather scarce in the majority of the
LCA reports consulted for this project. As far as the production of the main material of the
carrier bags is concerned, more datasets were available for LDPE, and fewer datasets were
available for other plastic types, such as PP, polyester, biopolymers and textiles. This did not
allow as much preliminary testing on the datasets employed as it was possible for virgin LDPE.
Higher data quality and availability would allow LCA practitioners to explore better alternative
materials for the production of carrier bags, especially data on recycled polymers and their
performance during manufacture and recycling.
The physico-chemical material composition used for modelling input-specific emissions in the
EASETECH LCA model allowed retrieving generic impacts for material groups, such as plas-
tic, paper, textile. The emissions mostly contributed to impacts to atmosphere via the incinera-
tion process, especially for plastic carrier bags.
Regarding the carrier bag manufacturing process, we observed that most of the production
impacts were ascribable to the production of the carrier bag material (Tables 13 – 21). The
material production process contributed less only in the LDPE and PP carrier bags manufac-
turing, but described most of the impacts from the manufacturing phase for most of the re-
maining carrier bags, as observed in previous LCA studies. Carrying out a streamlined LCA
The Danish Environmental Protection Agency / LCA of grocery carrier bags
81
considering only the production of the carrier bags’ main material would have underestimated
the impacts for LDPE and PP. However, even if for LDPE carrier bags most of the production
emissions arise from manufacturing phase (energy and ancillary material requirements), these
carrier bags are still providing the overall best environmental performance. In general, manu-
facturing data quality was mostly sensitive when bags were composed of light material or
material with low associated impacts.
For the modelling of the virgin LDPE waste bin bag we employed a dataset representing lower
quality LDPE than the one used for modelling LDPE carrier bags. The use of this dataset re-
sulted in lower savings from avoiding production and disposal of a waste bin bag. If we had
modelled the waste bin bag as the LDPE carrier bags, savings from replacing a waste bin bag
would have been even higher. Still, even using a conservative assumption for the production
data of the waste bin bag, reuse as waste bin bag was one of the most preferable end-of-life
options, especially for low weight and non-fossil carbon carrier bags (LDPE, paper, biopoly-
mer). If the waste bin bag was made of recycled polymer material, we expect that the impacts
connected to its production would have been slightly lower. In this case, the carrier bag sce-
narios that would be mostly affected would be the ones associated with the lightest carrier bag
weight: LDPE, paper, biopolymer. These carrier bags would present slightly lower benefits
from EOL3, but still result among the carrier bags with the overall lowest associated impacts
for EOL1.
The large transportation distances were considered conservative. Although distribution did not
largely contribute to the impacts, knowing the exact location of the facilities, especially the
recycling facilities assumed to be in Europe, would probably lower the impacts connected to
transportation. Lower transportation distances are especially expected to slightly reduce the
impacts of the EOL2 scenarios.
We did not find any available specific end-of-life data for recycled polymers, therefore we
could not apply specific higher losses during material production and recovery. If higher losses
would occur during manufacturing and recovery, there would be higher impacts related to the
production of the carrier bag with recycled material, as well as lower revenues from the recy-
cling process. This would affect the result for EOL2 as preferable waste management option
for PETrec.
Regarding the critical assumptions highlighted in Section 3, rounding to two bags when the
functionality expressed in the functional unit was not provided resulted in larger impacts for
bags that did not comply with the functional unit. In particular, the organic cotton bag provided
considerably high impacts.
Moreover, using virgin LDPE to model recycled LDPE resulted in higher impacts from the
production phase of the LDPErec carrier bag, but also to higher revenues from recycling. In-
deed, the recycled material is going to substitute production of virgin material instead of recy-
cled polymer.
The assumption of lower yield used to model the production of organic cotton increased the
impacts connected to its production, as can be seen from the contribution analyses in Table 19
and 20. However, the use of two bags in order to comply for the functional unit for organic
cotton bags influenced the results to a larger extent. For example, comparing the climate
change score for one organic cotton bag (5.4 kg CO2-eq/bag, Table 19) and for one conven-
tional cotton bag (3.9 kg CO2-eq/bag, Table 20), we obtain the following:
5.43.910038%
3.9
82 The Danish Environmental Protection Agency / LCA of grocery carrier bags
5.423.9100 %
77
1
3.9
Where 38 % represents the increase in climate change impact with respect to conventional
cotton by using a lower yield for organic cotton, and 177 % represents the Increase in climate
change impact with respect to conventional cotton by using 2 bags for organic cotton. 38 % is
higher than the assumed yield (-30 %) because organic cotton bags presented a slightly larger
weight with respect to conventional cotton bags.
If we had included the additional data on the conventional cotton bag pointed out by the pro-
ject partners after the first iteration of the report (please see Section 2), the average weight
associated to the conventional cotton bag would have lowered to 194.6 grams from the initial
232 grams (see Table 2), and the volume would have been 28.3 litres. The number of bags
required to fulfil the functional unit would have still been 1, but the lower weight would have
lowered the impacts (for example, we calculated 16 % lower impacts for climate change) and
lowered the number of reuse times by roughly 10 times. These considerations about volume of
the organic cotton bag and the weight of the conventional cotton bag will be expanded further
in a dedicated part about design considerations (please see Section 7).
As far as the choice for the marginal energy technologies is concerned, using a non-future
marginal energy would have entailed having coal in the energy mix, and would have provided
higher savings from energy recovery in the incineration process, especially for climate change.
Considering recycling feasible for biopolymer and textile carrier bags would mean allowing for
the recovery of these materials through separate collection and re-processing, therefore ulti-
mately lowering the impacts connected to the production of the carrier bags. However, specific
attention should be required to the substituted materials from such recovery processes, espe-
cially for cotton, which is unlikely to substitute production of primary cotton.
Lastly, in case the carrier bags cannot fulfil the functionality of waste bin bags, EOL3 should
not be considered as a viable option.
The choice of reference flow, the use of virgin LDPE data for LDPErec and reuse as waste bin
bag only for LDPE carrier bags were tested in a sensitivity analysis, which is provided in Sec-
tion 7.
The Danish Environmental Protection Agency / LCA of grocery carrier bags
83
7. Sensitivity analysis: critical
assumptions
This Section evaluates whether and in what measure a selection of the modelling choices and
critical assumptions identified in the LCA methodology Section (Section 3) influence the re-
sults. The results for the most preferable disposal option and carrier bag, as well as number of
primary reuse times, were re-calculated according to alternative modelling choices.
7.1
Choice of reference flow: rounding
The choice of calculating the reference flow by rounding to two carrier bags when one was not
sufficient to comply with the functional unit was tested by calculating the required number of
bags with fractions. This sensitivity analysis is based on the fact that the rounding to two bags
might provide a large overcapacity with respect to the functional unit. We also wanted to test
the effect on the results on “optimizing” the carrying capacity of the bags instead of just as-
suming that another bag of the same type would be bought by the customers.
The reference flow of this sensitivity analysis step was re-calculated for the bags that did not
comply with the functional unit and that required two bags (as shown in Table 3): LDPEs,
LDPErec, BP, PAP, PAPb and COTorg. The number of substituted waste bin bags was re-
calculated as well (Table 25). The effect of using fractions instead of rounding to another bag
has also lowered the number of substituted waste bin bags for the corresponding carrier bags.
For the bags that could provide more volume and weight holding capacity than the average
LDPE carrier bag (for example woven PP and conventional cotton) one bag was considered
instead of the fraction, and the number of substituted waste bin bags was left unchanged.
The reference flow change did not influence the preferred disposal option for each carrier bag.
The hierarchy of the most preferable carrier bag option for each impact category changed only
slightly. Paper obtained comparatively better results in human toxicity, cancer effects, and in
resource depletion, fossil, than in the present study, due to the lower environmental costs
related to the production of the carrier bag. The emissions related to production were larger
when the number of bags per reference flow was rounded to two. In general, LDPE carrier
bags still resulted as the carrier alternative providing the overall best performance in the high-
est number of impact categories, with LDPEs now providing the overall best performance
within virgin LDPE carrier bags.
The reference flow change for some of the carrier bags mostly influenced their calculated
number of reuse times. Table 26 shows that LDPEs and COTorg were the carrier bags that
considerably lowered the number of reuse times. In particular, when the reference flow was
not rounded, organic cotton presented less than half of the calculated number of reuse times
than what previously calculated, both for climate change and for all impact categories. The
results highlight the importance of the design of the bags, which is going to be discussed fur-
ther in a dedicated paragraph.
LDPEs, BP and PAP provided a negative number of reuse times, which signifies that these
carrier bag types provided a better environmental performance for climate change than the
average LDPE carrier bag. Across all impact categories, LDPE carrier bags provided a similar
performance, while heavier fossil carbon-based carrier bags, paper and biopolymer, presented
a generally higher number of calculated reuse times. Calculated number of reuse times for BP
and PAP was halved when considered across all impact categories.
84 The Danish Environmental Protection Agency / LCA of grocery carrier bags
Table 25. Reference flow and number of substituted bin bags used for the scenario
analysis.
Weight holding
Reference flow Number of sub-
Scenario
Volume
Reference flow
Capacity
(number of bags
stituted bin
name
enough?
calculation
enough?
needed)
bags
LDPEavg
Yes
Yes
Not changed
1.0
1.0
𝑉𝑜𝑙𝑢𝑚𝑒 𝐿𝐷𝑃𝐸𝑎𝑣𝑔 𝑊𝑒𝑖𝑔ℎ𝑡 ℎ𝑜𝑙𝑑. 𝐿𝐷𝑃𝐸𝑎𝑣𝑔
LDPEs
No
No
𝑀𝑎𝑥 (
,
)
𝑉𝑜𝑙𝑢𝑚𝑒 𝐿𝐷𝑃𝐸𝑠
𝑊𝑒𝑖𝑔ℎ𝑡 ℎ𝑜𝑙𝑑. 𝐿𝐷𝑃𝐸𝑠
1.2
1.0
LDPEh
Yes
Yes
Not changed
1.0
1.1
𝑉𝑜𝑙𝑢𝑚𝑒 𝐿𝐷𝑃𝐸𝑎𝑣𝑔 𝑊𝑒𝑖𝑔ℎ𝑡 ℎ𝑜𝑙𝑑. 𝐿𝐷𝑃𝐸𝑎𝑣𝑔
LDPErec
No
No
𝑀𝑎𝑥 (
,
)
𝑉𝑜𝑙𝑢𝑚𝑒 𝐿𝐷𝑃𝐸𝑟𝑒𝑐 𝑊𝑒𝑖𝑔ℎ𝑡 ℎ𝑜𝑙𝑑. 𝐿𝐷𝑃𝐸𝑟𝑒𝑐
1.1
1.1
PP
Yes
Yes
Not changed
1.0
1.3
PPwov
Yes
Yes
Not changed
1.0
1.6
PETrec
Yes
Yes
Not changed
1.0
1.9
PETpol
Yes
Yes
Not changed
1.0
1.4
𝑉𝑜𝑙𝑢𝑚𝑒 𝐿𝐷𝑃𝐸𝑎𝑣𝑔 𝑊𝑒𝑖𝑔ℎ𝑡 ℎ𝑜𝑙𝑑. 𝐿𝐷𝑃𝐸𝑎𝑣𝑔
BP
No
No*
𝑀𝑎𝑥 (
,
)
𝑉𝑜𝑙𝑢𝑚𝑒 𝐿𝐷𝑃𝐸𝑟𝑒𝑐 𝑊𝑒𝑖𝑔ℎ𝑡 ℎ𝑜𝑙𝑑. 𝐿𝐷𝑃𝐸𝑟𝑒𝑐
1.0
1.0
𝑊𝑒𝑖𝑔ℎ𝑡 ℎ𝑜𝑙𝑑. 𝐿𝐷𝑃𝐸𝑎𝑣𝑔
PAP
Yes
No*
𝑊𝑒𝑖𝑔ℎ𝑡 ℎ𝑜𝑙𝑑. 𝑃𝐴𝑃
1.0
1.0
𝑊𝑒𝑖𝑔ℎ𝑡 ℎ𝑜𝑙𝑑. 𝐿𝐷𝑃𝐸𝑎𝑣𝑔
PAPb
Yes
No*
𝑊𝑒𝑖𝑔ℎ𝑡 ℎ𝑜𝑙𝑑. 𝑃𝐴𝑃𝑏
1.0
1.0
𝑉𝑜𝑙𝑢𝑚𝑒 𝐿𝐷𝑃𝐸𝑎𝑣𝑔
COTorg
No
Yes
𝑉𝑜𝑙𝑢𝑚𝑒 𝐶𝑂𝑇𝑜𝑟𝑔
1.1
1.0
COT
Yes
Yes
Not changed
1.0
1.2
COM
Yes
Yes
Not changed
1.0
1.4
* In this sensitivity analysis the weight holding capacity of 12.0 kg of paper and biopolymer bags was considered effec-
tive.
Table 26. Calculated number of primary reuse times for each carrier bag in the rows in
comparison to LDPEavg, EOL3, for the reference flow in Table 25. Results are provided
for the climate change impact category and across impact categories. Results for CO-
Torg, COT and COM have been rounded. Results in brackets report the previously cal-
culated results in Table 24 for the carrier bags with a changed reference flow.
LDPEavg, EOL3
Climate change
All impact categories
EOL1
EOL2
EOL3
EOL1
EOL2
EOL3
LDPEs
0.3 (0.5)
0.0 (0.1)
-0.2 (0.00)
0.9 (1.2)
4.1 (5.0)
0.2 (0.0)
LDPEh
0.9
0.4
0.3
1.7
6.1
0.3
LDPErec
0.8 (2.2)
0.3 (1.4)
0.2 (1.2)
1.7 (1.7)
6.2 (6.1)
0.5 (0.3)
PP
8.0
6.0
7.3
38
52
37
PPwov
6.8
5.0
5.9
33
45
32
PETrec
9.6
8.2
8.6
95
84
96
PETpol
2.6
1.9
1.9
35
28
35
BP
-0.4 (0.2)
-
-0.9 (-0.8)
21 (41)
-
22 (42)
PAP
-0.6 (-0.2)
-0.3 (0.5)
-1.1 (-1.3)
22 (42)
38
22 (43)
PAPb8
0.3
0.6
-0.2
22 (42)
38
22 (43)
COTorg
84 (150)
-
83 (149) 10000 (20000)
- 10000 (20000)
COT
53
-
52
7100
-
7100
8 The highest value for bleached paper was increased to be equal to the value for unbleached paper
The Danish Environmental Protection Agency / LCA of grocery carrier bags
85
COM
23
-
23
870
-
870
7.2
Secondary reuse as a waste bin bag allowed only for LDPE
carriers
In this Section, results are presented considering that secondary reuse as a waste bin bag
(EOL3) could be possible only for LDPE carrier bags. This modelling choice would represent
the choice of allowing secondary reuse as a waste bin bag only for the carrier bags that can
fully provide for the same functionality. The results for the best disposal option for each carrier
bag are provided in Table 26. As previously discussed, reuse as waste bin bag before being
incinerated is the best disposal option for LDPE carrier bags. For heavier plastic bags recy-
cling resulted often one of the best options, provided that the carrier bags can be effectively
recycled. For the remaining bags, incineration was the disposal option that provided the lowest
environmental impacts.
As far as the hierarchy of results is concerned, the carrier bags providing the lowest impacts
have only slightly changed. Incineration of paper and biopolymer carrier bags and secondary
reuse of the LDPE carrier bags still provided the lowest climate change environmental im-
pacts. For the other impact categories, LDPE carrier bags represented the alternative with the
overall lowest environmental impacts, as already observed. The results indicate that allowing
secondary reuse as waste bin bag only for LDPE carrier bag provides little influence on the
hierarchy of the most favourable carrier bag alternative for each impact category. For the
number of reuse times, if EOL3 is not allowed for all carrier bag alternatives other than LDPE
carrier bags, non-LDPE carrier bags have to be reused in average at least one additional time
before being incinerated. The results correspond to Table 24 presented previously, without
considering the EOL3 column for the non-LDPE carrier bags.
86 The Danish Environmental Protection Agency / LCA of grocery carrier bags
Table 26. Disposal options providing the lowest environmental impacts for each of the
carrier bags in the rows and each of the impact categories in the columns. The colour
scale refers to the disposal option: red was assigned to incineration (EOL1), blue to
recycling (EOL2), and green to secondary reuse as a waste bin bag (EOL3). EOL3 was
considered possible only for LDPE carrier bags.
Scenario
HTN
RD
Wa-
CC
OD
HTC
PM
IR
POF
TA
TE
FE
ME
ET
RD
name
C
fos
ter
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
LDPEavg
3
1
3
1
3
3
3
3
3
1
3
3
3
3
3
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
LDPEs
3
1
3
1
3
3
3
3
3
1
3
3
3
3
1
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
LDPEh
3
1
3
1
3
3
3
3
3
1
3
3
3
3
3
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
LDPErec
3
1
3
1
3
3
3
3
3
1
3
3
3
3
3
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
PP
2
1
1
1
1
1
1
1
1
1
1
1
2
1
1
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
PPwov
2
1
1
1
1
1
1
1
1
1
1
1
2
1
1
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
PETrec
2
1
2
1
1
1
1
1
1
2
1
1
2
2
2
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
PETpol
2
1
2
1
1
1
1
1
1
2
1
1
2
2
2
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
BP
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
PAP
1
1
1
1
1
1
1
1
1
1
1
1
1
2
1
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
PAPb
1
1
1
1
1
1
1
1
1
1
1
1
1
2
1
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
COM
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
COTorg
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
EOL
COT
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
The Danish Environmental Protection Agency / LCA of grocery carrier bags
87
7.3
Recycled LDPE
Since the dataset for recycled LDPE was missing in the Ecoinvent database, the recycled
LDPE carrier bag was modelled modifying the virgin LDPE production dataset. As shown in
Appendix B, for PET the recycled inventory dataset presents lower emissions than the virgin
inventory dataset for all impact categories. In this sensitivity analysis, the virgin LDPE produc-
tion inventory of emissions used for the recycled LDPE carrier bag was lowered by 25 %. This
signified that the environmental costs for the production of LDPE were lowered by the same
extent for all environmental indicators, as well as the benefits from the recycling of recycled
LDPE.
The results obtained by the recycled LDPE carrier bags lowered for all impact categories, as
shown in Table 27 below. Table 27 provides the percent variation of the newly tested LDPErec
scenario with the results presented in Tables (10 – 12). Climate change results lowered by 12
% for EOL1, by 18 % for EOL2, and by 8 % for EOL3. For human toxicity, cancer effects
(HTNC), and freshwater eutrophication (FE), the Table shows positive percent variation be-
cause the original result scores were already negative numbers. The highest variations oc-
curred for human toxicity, cancer effects, particulate matter (PM), photochemical ozone for-
mation (POF), terrestrial acidification (TA), terrestrial eutrophication (TE) and marine eutrophi-
cation (ME).
The preferred management option for LDPErec, which was mostly EOL3 for the different im-
pact categories, did not change. The hierarchy of the carrier bags providing the lowest perfor-
mance for each environmental indicator changed for the impact categories of particulate mat-
ter, photochemical ozone formation, terrestrial and freshwater eutrophication, where LDPErec
provided the best performance. The results for the remaining impact categories did not
change: virgin LDPE provided the overall best performance, along with paper and biopolymer
for the climate change impact category.
The number of reuse times was recalculated as well and it is presented in Table 28. Consider-
ing the end-of-life scenario where LDPErec provides the best performance, which is EOL3,
The number of reuse times lowered only slightly: by 0.4 for the climate change impact catego-
ry, and by 0.5 across all impact categories. The results are more comparable to those ob-
tained for virgin LDPE carrier bags in Table 24, but are still larger because of the two bags
required in order to provide for the functionality expressed in the functional unit.
88 The Danish Environmental Protection Agency / LCA of grocery carrier bags
Table 27. Percent variation from the LDPErec scenario results presented in Tables 10 –
12 obtained by lowering the virgin LDPE material production impacts by 25 %.
CC
OD
HTC
HTNC
PM
IR
POF
TA
TE
FE
ME
ET
RDfos RD
Water
EOL1 -12% -7% -10%
2%
-42% -4% -31% -53% -116%
8%
-43% -12% -26% -1%
-1%
EOL2 -8%
-1%
-5%
45%
-11% -2% -17% -18%
-20%
-3% -16% -5%
-16% -1%
-1%
EOL3 -18% -6% -12%
2%
-64% -6% -47% -76% -194% 12% -61% -17% -39% -1%
-2%
Table 28. Calculated number of primary reuse times for LDPErec carrier bag in the rows
in comparison to LDPEavg, EOL3, for the reference flow in Table 3. Results are provid-
ed for the climate change impact category and across impact categories. The inventory
dataset for the production of virgin LDPE was lowered by 25 %. Numbers in brackets
are the previous results for LDPErec reported in Table 24.
LDPEavg, EOL3
Climate change
All impact categories
EOL1
EOL2
EOL3
EOL1
EOL2
EOL3
LDPErec
1.8 (2.2)
1.2 (1.4)
0.8 (1.2)
2.0 (3.4)
9.1 (11.7)
1.1 (1.6)
7.4
Final remarks on sensitivity analysis
The tested methodological assumptions allowed for understanding of the robustness of the
results obtained with respect to critical assumptions taken for this LCA study. Table 29 sum-
marizes the results of the sensitivity analysis on the assumptions.
The assumptions tested modified the best end-of-life option for each of the carrier bags as-
sessed only when reuse as waste bin bag was not allowed for non-LDPE carriers. In general,
after reusing as many times as possible the carrier bag, it could be reused as waste bin bag
before being incinerated when possible. For paper and biopolymer bags, this can occur with
limited waste weight and by avoiding wet waste and sharp edges. For heavier carriers, such
as PP, PET and polyester, recycling may be an option, but providing benefits only in a limited
number of impact categories.
The hierarchy of the carrier bags providing the best disposal for each of the impact categories
considered, varied for some impact categories when lower impacts were associated to recy-
cled LDPE production. Overall, the hierarchy did not change with respect to the general con-
clusions observed in the discussion section: light carrier bags, such as LDPE, paper and bi-
opolymer, are the carrier bags providing the lowest impacts across the impact categories as-
sessed.
Lastly, the number of reuse times considerably changed when the reference flow was
changed, but mostly for the organic cotton bag. For this carrier bag type, rounding to two carri-
er bags when the volume of one bag was not enough considerably influenced the results.
Considering a fraction of the reference flow (1.1) instead of rounding, required 45 % less cot-
ton to be produced; this considerably lowered the impacts connected to cotton production. As
already observed in the discussion of the results, it is important to notice that the difference
connected to the reference flow choice is larger than the assumption on the organic cotton
yield presented in the assumptions section. The calculated number of reuse times for the or-
ganic cotton bag is however still very high.
The Danish Environmental Protection Agency / LCA of grocery carrier bags
89
Table 29. Overview of the changes in the results induced by changes in the assump-
tions for the reference flow, allowed secondary reuse and different calculation method
for the reuse times.
Induced change
Tested assumption
Best end-of-life option for
Hierarchy of carrier bags for each Calculate number of primary
each carrier bag
impact category
reuse times
Yes, especially for organic
Reference flow
Not changed
Not changed
cotton: number of reuse
times reduced by half
EOL3 not allowed for non-LDPE
Yes,
Not changed
+1 (average)
carriers
EOL1 instead of EOL3
LDPErec modelled by lowering
LDPErec best option for PM,
LDPE production impacts by
Not changed
-1 for LDPErec
POF, TE, FE
25%
7.4.1 Carrier bag design
The results of the sensitivity analysis suggest that for the carrier bags with the highest weight
and with the highest impacts connected to production, the ability to provide for the functionality
expressed in the functional unit is essential. In particular, if Danish retailers want to provide a
multiple-use carrier bag alternative to LDPE carrier bags that is made of cotton or textile-based
composite materials, their attention should be placed on the weight of the bag and on its vol-
ume. The textile bag should preferably be of light weight and with enough volume to provide
for the same capacity of LDPE carrier bags. The example provided in the discussion of the
results showed that using a conventional cotton bag of a lower weight had lowered the number
of reuse times by 10 units.
All the multiple use bags (PP, PET, Cotton etc.) could carry significantly more weight than the
reference flow, but varied highly in volume. This indicates that it is possible to design bags that
can be high in both volume and weight. For some consumers the weight could be the limiting
factor, but for other consumers it could for some bags mean that weight holding capacity
would be the limiting factor. No matter the consumer preference, there is not a rational for not
optimizing the volume per material weight.
As far as the carrier bag material is concerned, organic cotton provides environmentally pref-
erable production conditions by avoiding the use of fertilizers and pesticides, but with a lower
yield. The lower production yield translates in overall higher environmental impacts connected
to its production, and to a higher required number of reuse times in order to “amortize” its
environmental production costs.
Regarding the material of the carrier bags, one more observation could be raised for the use of
recycled polymers for the manufacturing of the carrier bags. If all the LDPE carrier bags had
the same volume capacity, weight holding capacity and thickness (and weight of the carrier
bag), the dataset for the production of recycled LDPE was available, the recycled LDPE would
result as the best option. This would be especially true for EOL3, since the recycled LDPE
would be substituting a virgin LDPE waste bin bag.
However, the virgin and recycled LDPE carrier bags examined for this LCA study had different
volume and weight holding capacities. In order for the recycled LDPE carrier bag to carry the
same volume as the virgin LDPE carrier bags, more than one bag would be required. This
increased the environmental impacts associated with the recycled LDPE carrier bag, and this
was the reason why it does not result as the best option between the carrier bags examined.
90 The Danish Environmental Protection Agency / LCA of grocery carrier bags
Indeed, the results for LDPErec were more influenced by the sensitivity analysis on the refer-
ence flow than the sensitivity analysis on the production data.
Lastly, it would be useful for customers to be reminded of the indicative number of reuse times
obtained by this report by adding this information on the multiple-use carrier bag, for example
“reuse me at least 10 times”, and together with a suggested end-of-life option “reuse me as
waste bin bag”, for example.
The Danish Environmental Protection Agency / LCA of grocery carrier bags
91
8. Conclusions
This study identified the best disposal option for each of the carrier bags available in Danish
supermarkets in 2017. In general, reusing the carrier bag as a waste bin bag is better than
simply throwing away the bag in the residual waste and it is better than recycling. Recycling
can potentially offer more benefits in the case of heavy plastic bags, such as PP, and PET.
Reuse as a waste bin bag is most beneficial for light carrier bags, such as LDPE, paper and
biopolymer. When reuse as a waste bin bag is not feasible, for example when the bag can
easily be punctured, torn, or wetted, incineration is the most preferable solution from an envi-
ronmental point of view.
In general, LDPE carrier bags, which are the bags that are always available for purchase in
Danish supermarkets, are the carriers providing the overall lowest environmental impacts
when not considering reuse. In particular, between the types of available carrier bags, LDPE
carrier bags with rigid handle are the most preferable. Effects of littering for this type of bag
were considered negligible for Denmark. Carrier bags alternatives that can provide a similar
performance are unbleached paper and biopolymer bags, but for a lower number of environ-
mental indicators. Heavier carrier bags, such as PP, PET, polyester, bleached paper and tex-
tile bags need to be reused multiple times in order to lower their environmental production
cost. Between the same bag types, woven PP carrier bags provided lower impacts than non-
woven PP bags, unbleached paper resulted more preferable than bleached paper, and con-
ventional cotton over organic cotton.
For all carrier bags, reuse as many times as possible before disposal is strongly encouraged.
This study also calculated how many times each bag would need to be reused in order to
lower its associated environmental impacts to the levels of the LDPE carrier bag. The number
of calculated reuse times varies if only one environmental indicator is observed, or if all envi-
ronmental indicators are taken into account.
The results are the following9:
Simple LDPE bags: Can be directly reused as waste bin bags for climate change, should
be reused at least 1 time for grocery shopping considering all other indicators; finally reuse
as waste bin bag.
LDPE bags with rigid handle: Can be directly reused as waste bin bags considering all
indicators; finally reuse as waste bin bag.
Recycled LDPE bags: Reuse for grocery shopping at least 1 time for climate change, at
least 2 times considering all indicators; finally reuse as waste bin bag.
PP bags, non-woven: Reuse for grocery shopping at least 6 times for climate change, and
up to 52 times considering all indicators; finally dispose with recyclables, otherwise reuse as
waste bin bag if possible, lastly incinerate.
9 The number of times for “all indicators” refers to the highest number of reuse times among those calcu-
lated for each impact category. For light carrier bags (LDPE, PP, PET...) the high numbers of reuse times
are given by a group of impact categories with similar high values. Conversely, for composite and cotton
the very high number of reuse times is given by the ozone depletion impact alone. Without considering
ozone depletion, the number of reuse times ranges from 50 to1400 for conventional cotton, from 150 to
3800 for organic cotton, and from 0 to 740 for the composite material bag. The highest number is due to
the use of water resource, but also to freshwater and terrestrial eutrophication. Results for the number of
reuse times for each impact category, minimum-maximum ranges and average number of reuse times
are provided in Appendix C.
92 The Danish Environmental Protection Agency / LCA of grocery carrier bags
PP bags, woven: Reuse for grocery shopping at least 5 times for climate change, at least
45 times considering all indicators; finally dispose with recyclables, otherwise reuse as
waste bin bag if possible, lastly incinerate.
PET bags: Reuse for grocery shopping at least 8 times for climate change, and up to 84
times considering all indicators; finally dispose with recyclables, otherwise reuse as waste
bin bag if possible, lastly incinerate.
Polyester bags: Reuse for grocery shopping at least 2 times for climate change, and up to
35 times considering all indicators; finally dispose with recyclables, otherwise reuse as
waste bin bag if possible, lastly incinerate.
Biopolymer bags: Can be directly reused as waste bin bags for climate change, should be
reused and up to 42 times for grocery shopping considering all other indicators. Finally, re-
use as waste bin bag if possible, otherwise incinerate.
Unbleached paper bags: Can be directly reused as waste bin bags for climate change,
should be reused and up to 43 times considering all other indicators. Finally, reuse as waste
bin bag if possible, otherwise incinerate.
Bleached paper bags: Reuse for grocery shopping at least 1 time for climate change, and
up to 43 times considering all indicators; reuse as waste bin bag if possible, otherwise incin-
erate.
Organic cotton bags: Reuse for grocery shopping at least 149 times for climate change,
and up to 20000 times considering all indicators; reuse as waste bin bag if possible, other-
wise incinerate.
Conventional cotton bags: Reuse for grocery shopping at least 52 times for climate
change, and up to 7100 times considering all indicators; reuse as waste bin bag if possible,
otherwise incinerate.
Composite bags: Reuse for grocery shopping at least 23 times for climate change, and up
to 870 times considering all indicators; reuse as waste bin bag if possible, otherwise inciner-
ate.
This study focused on identifying the number of reuse times based on the environmental per-
formance of the carrier bags. The results obtained on the minimum number of reuse times are
intended to raise the discussion among the stakeholders on the effective expected lifetime of
each carrier bag. While the calculated number of reuse times might be compliant with the
functional lifetime of PP, PET and polyester carrier bags, but might surpass the lifetime of
bleached paper, composite and cotton carriers, especially considering all environmental indi-
cators. In addition it should be kept in mind that the reuse times calculated are held up against
a use of a reference bag a single time. If the reference bag is reused, it would mean that the
reuse time of the other bags would increase proportionally.
In particular, the results of the present assessment have highlighted the importance of the
design of the carrier bag and its functionality, especially for cotton carriers. In order to lower
the number of reuse times, designs with light fabric and large volumes should be preferred.
These design differences can largely lower the impacts. However, the required number of
reuse times for all impact categories may still be unfeasible and more than the lifetime of the
bag.
The Danish Environmental Protection Agency / LCA of grocery carrier bags
93
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economic performance of organic and conventional cotton-based farming systems--
results from a field trial in India. PLoS One 8, e81039. doi:10.1371/journal.pone.0081039
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in the United States, Environmen. ed. Clemson University Digital Press, Clemson, SC.
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Danish household waste. Waste Manag. 29, 1251–1257.
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discarded textiles – LCA of different treatment pathways. Copenhagen, Denmark.
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The Danish Environmental Protection Agency / LCA of grocery carrier bags
95
Appendix A.
Life Cycle
Inventories (LCIs)
This Section provides the data and corresponding references utilized for the present LCA
study.
Table A1. Material composition used for each carrier bag,
Scenario Material
Material composition used
LDPEAVG LDPE
Soft plastic (Riber et al., 2009)
LDPEs
LDPE simple
Soft plastic (Riber et al., 2009)
LDPEh
LDPE rigid handle
Soft plastic (Riber et al., 2009)
LDPErec
LDPE recycled
Soft plastic (Riber et al., 2009)
P2a
PP non-woven
Soft plastic (Riber et al., 2009)
PPwov
PP woven
Soft plastic (Riber et al., 2009)
PETREC PET recycled
Soft plastic (Riber et al., 2009)
PETPOL
Polyester
Soft plastic (Riber et al., 2009)
BP
Biopolymer
Soft plastic (Riber et al., 2009); modified according to Razza (2014)
PAP
Paper
Paper and carton containers (Riber et al., 2009)
PAPB
Paper
Paper and carton containers (Riber et al., 2009)
COTORG Cotton organic
Textiles (Riber et al., 2009)
COT
Cotton conventional
Textiles (Riber et al., 2009)
COM
Jute, PP, cotton
Textiles (Riber et al., 2009)
W1
LDPE
Soft plastic (Riber et al., 2009)
All
Packaging: cardboard
Other clean cardboard (Riber et al., 2009)
96 The Danish Environmental Protection Agency / LCA of grocery carrier bags
Table A2. Amount of material needed for production of the carrier bags and the waste
bin bag, percent lost during production and final weight of the bag.
Amount material produced Percent lost during manufacturing
Weight carrier bag
Scenario
(kg/bag)
(%/bag)
(kg/bag)
LDPEavg
0.025
5.15
0.024
LDPEs
0.019
5.15
0.018
LDPEh
0.031
5.15
0.029
LDPErec
0.026
5.15
0.025
PP
0.144
5.05
0.137
PPwov
0.125
5.05
0.119
PETrec
0.159
5.15
0.151
PETpol
0.048
5.05
0.046
BP
0.018
1.03
0.018
PAP
0.045
5.15
0.042
PAPb
0.045
5.15
0.042
COTorg
0.254
0.98
0.252
COT
0.234
0.98
0.232
COM
0.282
0.98
0.279
W1
0.010
5.15
0.009
Table A3. Ecoinvent processes utilized to model the production of the material of the
carrier bags. All datasets were retrieved from Ecoinvent version 3.4 (2017), consequen-
tial.
Scenario
Ecoinvent process name
LDPEavg
Market for polyethylene, low density, granulate; GLO (kg)
LDPEs
Market for polyethylene, low density, granulate; GLO (kg)
LDPEh
Market for polyethylene, low density, granulate; GLO (kg)
LDPErec
Market for polyethylene, low density, granulate; GLO (kg)
PP
Market for polypropylene, granulate; GLO (kg)
PPwov
Market for polypropylene, granulate; GLO (kg)
PETrec
Market for polyethylene terephthalate, granulate, amorphous, recycled; RoW (kg)
PETpol
Market for polyethylene terephthalate, granulate, amorphous; GLO (kg)
BP
Market for polyester-complexed starch biopolymer; GLO (kg)
PAP
Kraft paper production, unbleached; RER (kg)
PAPb
Kraft paper production, bleached; RER (kg)
COTorg
Market for textile, woven cotton; GLO (kg)
COT
Market for textile, woven cotton; GLO (kg)
Market for textile, jute; GLO (kg)
COM
Market for polypropylene, granulate; GLO (kg)
Market for textile, woven cotton; GLO (kg)
W1
Packaging film production, low density polyethylene; RER (kg)
The Danish Environmental Protection Agency / LCA of grocery carrier bags
97
Table A4. Ecoinvent processes utilized to model the treatment of residues from produc-
tion, for each carrier bag. All datasets were retrieved from Ecoinvent version 3.4 (2017),
consequential.
Scenario
Ecoinvent process name
Treatment of waste polyethylene, municipal incineration; Europe
LDPEAVG, LDPEs, LDPEh, LDPErec, W1
without Switzerland (kg)
Treatment of waste polypropylene, municipal incineration; CH
P2a, PPwov
(kg)
Treatment of waste polyethylene terephthalate, municipal incin-
PETREC, PETPOL
eration; Europe without Switzerland (kg)
Treatment of waste paperboard, municipal incineration; Europe
BP, PAP, PAPB
without Switzerland (kg)
Treatment of waste textile, soiled, municipal incineration; RoW
COTORG, COT, COM
(kg)
98 The Danish Environmental Protection Agency / LCA of grocery carrier bags
Table A5. Carrier bag production: material and energy requirements. The literature ref-
erences are provided as superscript. The references were used to obtain average con-
sumption values.
Titanium
Cotton
PP
Packaging
Electricity
Heat
Water
Ink
Glue
Scenario
dioxide
thread
thread
amount
kWh/kg
MJ/kg
L/kg
kg/kg
kg/kg
kg/kg
kg/kg
kg/kg
kg/kg
0.741
1.522a
-
0.034
0.011a
-
-
-
0.048
0.998a
0.032a
0.078a
LDPEAVG,
LDPEs,
0.987a
0.070b
0.042b
LDPEh,
0.490b
0.001c
0.024c
LDPErec
0.609c
(LDPE)
0.950c
0.410d
1.854
1.308
0.807a
-
0.054
0.007
0.004a
-
0.069
0.612b
2.616a
0.067d
0.004a
0.087a
PP, PPwov
1.500c
Negligiblee
0.042d
0.010b
0.069b
(PP)
2.204d
0.009d
0.050c
3.100d
0.006d
PETREC
1.854
1.308
0.807a
-
0.054
0.007
0.004a
-
0.069
(PET)
PETPOL (Pol-
1.854
1.308
0.807a
-
0.054
0.007
0.004a
-
0.069
yester)
1.112
-
1.343a
0.021a
0.005a
-
-
-
0.043
BP (Biopoly-
1.066a
Negligiblee
0.054a
mer)
0.858c
0.033c
1.413c
0.216
-
-
-
0.014a
-
-
0.027
0.049
PAP, PAPB
0.042b
0.027a
0.058a
(Paper)
0.390d
0.027b
0.040b
COTORG,
0.006a
0.092a
-
-
-
0.007a
-
-
0.108a
COT (Cotton)
COM (Compo-
0.006a
0.092a
-
-
-
0.007a
-
-
0.108a
site)
a (Edwards and Fry, 2011)
b (Kimmel and Cooksey, 2014)
c (Mori et al., 2013)
d (Muthu and Li, 2014)
e (Khoo and Tan, 2010)
The Danish Environmental Protection Agency / LCA of grocery carrier bags
99
Table A6.
With reference to the energy and material requirements listed in Table
A4, this table provides the Ecoinvent datasets utilized for the corresponding energy and
material requirements. For completeness, the table reports in which scenarios the da-
tasets were used.
Ancillary material
Scenario
LDPEAVG
Ecoinvent process
LDPEs
PP
PAP
COTORG
Type
(v 3.4, conse-
PETREC
PETPOL
BP
COM
LDPEh
PPwov
PAPB
COT
quential)
LDPErec
Market group for
electricity, high
Electricity
X
X
X
X
X
X
X
X
voltage; RER
(kWh)
Market group for
heat, district or
Heat
X
X
X
X
X
X
industrial, natural
gas; RER (MJ)
Market for tap
water; Europe
Water
X
X
X
X
without Switzer-
land (kg)
Market for titani-
Titanium
um dioxide; RoW
X
X
dioxide
(kg)
Market for printing
ink, rotogravure,
without solvent, in
Ink
X
X
X
X
X
X
55% toluene solu-
tion state; GLO
(kg)
Market for textile,
Cotton
woven cotton;
X
X
X
X
X
thread
GLO (kg)
Market for po-
PP thread lypropylene, gra-
X
X
X
nulate; GLO (kg)
Bitumen adhesive
Glue
compound pro-
X
duction, hot; RER
Corrugated board
Packaging box production;
X
X
X
X
X
X
X
X
RER (kg)
100 T
he Danish Environmental Protection Agency / LCA of grocery carrier bags
Table A7. Transportation distances utilized in this LCA study.
Transportation process
Distance
EOL1
EOL2
EOL3
Transport of packaging material to carrier bag production
2000 km
X
X
X
facility (EU)
Transport of carrier bag to supermarket (EU-DK)
2000 km
X
X
X
Collection of packaging from supermarkets (DK)
15 km
X
X
X
Transport to packaging recycling (DK-EU)
2000 km
X
X
X
Collection of residual waste (DK)
10 km
X
X
Transport fly ash (DK-EU)
500 km
X
X
Transport bottom ash (DK-EU)
100 km
X
X
Collection of recyclables (DK)
15 km
X
Transportation to sorting (DK)
500 km
X
Transportation to recycling (DK-EU)
2000 km
X
Table A8. Ecoinvent process used in order to model transportation.
Transportation process
Ecoinvent process (v 3.4, consequential)
Transport of packaging material to carrier bag production
facility (EU)
Transport of carrier bag to supermarket (EU-DK)
Transport to packaging recycling (DK-EU)
Transportation to sorting (DK)
Transport, freight, lorry 16-32 metric ton,
Transport fly ash (DK-EU)
EURO6; RER
Transport bottom ash (DK-EU)
(metric ton*km)
Transportation to recycling (DK-EU)
Collection of packaging from supermarkets (DK)
Collection of recyclables (DK)
Collection of residual waste (DK)
Table A9. Material losses during recycling of single-wall corrugated cardboard packag-
ing.
Material fraction
Recycled (%)
Residues (%)
Other clean cardboard (Riber et al., 2009)
91
9
Table A10. Material and energy requirements and corresponding Ecoinvent processes
used for the modelling of the recycling of single-wall corrugated cardboard packaging.
Material and energy requirements were obtained from Skjern Papirfabrik (2005).
Ecoinvent process name (v 3.4, consequential)
Amount Unit
Market group for tap water; RER
17 kg/kg Total Wet Weight
Market group for electricity, high voltage; RER
1.5 kWh/kg Total Wet Weight
Natural gas, from high pressure network (1-5 bar), at service station; CH
0.069 kg/kg Total Wet Weight
Linerboard production, kraftliner; RER
-0.9 kg/kg Total Wet Weight
The Danish Environmental Protection Agency / LCA of grocery carrier bags
101
Table A11. Emissions during recycling of single-wall corrugated cardboard packaging.
Elementary exchange
Compartment Sub compartment Amount Unit Per
Nitrogen oxides
air
unspecified
8.80E-05 kg
kg Total Wet Weight
Carbon dioxide, fossil
air
unspecified
0.18
kg
kg Total Wet Weight
Sulfur dioxide
air
unspecified
0.0001
kg
kg Total Wet Weight
COD, Chemical Oxygen Demand
water
surface water
0.0011
kg
kg Total Wet Weight
Nitrogen
water
surface water
6.00E-05 kg
kg Total Wet Weight
Phosphate
water
surface water
2.50E-06 kg
kg Total Wet Weight
Suspended solids, unspecified
water
surface water
0.00016 kg
kg Total Wet Weight
Particulates, > 2.5 um, and < 10um air
unspecified
2.80E-05 kg
kg Total Wet Weight
Table A12. Ecoinvent process used for modelling the treatment of residues from pack-
aging recycling.
Ecoinvent process name (v 3.4, consequential)
Amount Unit
Treatment of waste paperboard, municipal incineration; Europe without Switzerland 1
kg/kg Total Wet Weight
Table A13. Material and energy requirements and corresponding Ecoinvent processes
used for the modelling of the incinerator technology. Material and energy requirements
were obtained from Vestforbrænding (2013). Electricity recovery was considered 22 %,
heat recovery 73 %. Please refer to Appendix B for the marginal electricity and heat
utilized.
Ecoinvent process name (v 3.4, consequential)
Amount
Unit
quicklime production, milled, packed; CH
0.00034
kg/kg Total Wet Weight
market for ammonia, liquid; RER
0.00153
kg/kg Total Wet Weight
activated carbon production, granular from hard coal; RER
0.00104
kg/kg Total Wet Weight
market for tap water; Europe without Switzerland
0.397
kg/kg Total Wet Weight
hydrochloric acid production, from the reaction of hydrogen with chlorine; RER
5.60E-06 kg/kg Total Wet Weight
market for sodium hydroxide, without water, in 50% solution state; GLO
2.40E-05 kg/kg Total Wet Weight
market for calcium carbonate, precipitated; GLO
0.00567
kg/kg Total Wet Weight
Marginal electricity, see Appendix B
-0.22/3.6 kWh/MJ
Marginal heat, see Appendix B
-0.73
MJ/MJ
Table A14. Emissions to the air, unspecified, Vestforbrænding (2013).
Elementary exchange
Amount
Unit
Carbon monoxide
3.30E-02
kg/kg Total Wet Weight
Dust
4.06E-03
kg/kg Total Wet Weight
HCl
6.58E-03
kg/kg Total Wet Weight
HF
2.70E-04
kg/kg Total Wet Weight
Manganese
1.12E-02
kg/kg Total Wet Weight
NH3
4.31E-03
kg/kg Total Wet Weight
Nickel
3.47E-06
kg/kg Total Wet Weight
Nitrogen Oxides (NOx)
5.49E-01
kg/kg Total Wet Weight
PAH (B[a]P-eq)
4.31E-06
kg/kg Total Wet Weight
PCDD/F
1.80E-11
kg/kg Total Wet Weight
SO2/SO3
1.08E-02
kg/kg Total Wet Weight
102 T
he Danish Environmental Protection Agency / LCA of grocery carrier bags
Table A15. Transfer coefficients to air emissions from input composition, Vestfor-
brænding (2013).
Parameter
Unit
Value
Hg
% Hg in
0.7476
Cd
% Cd in
0.0064
Pb
% Pb in
0.0008
Cr
% Cr in
0.0394
Cu
% Cu in
0.003
As
% As in
0.012
Ni
% Ni in
0.033
Sb
%Sb in
0.119
Table A16. Transfer coefficients for degradation and residues for the soft plastic mate-
rial fraction, Vestforbrænding (2013).
Fraction Degradation
Fly ash
Scrap metals
Bottom ash
name
Water
VS
Ash
Water
VS
Ash
Water
VS
Ash
Water
VS
Ash
(%)
(%TS)
(%TS)
(%)
(%TS)
(%TS)
(%)
(%TS)
(%TS)
(%)
(%TS)
(%TS)
Soft
100
99.9
0
0
0
12.6
0
0
0
0
0.1
87.4
plastic
Table A17. Emissions to water, Vestforbrænding incinerator.
Elementary exchange
Compartment
Value
Unit
Antimony
water
8.80E-06
kg/kg Total Wet Weight
Arsenic
water
5.60E-07
kg/kg Total Wet Weight
Barium
water
7.20E-06
kg/kg Total Wet Weight
Cadmium
water
9.67E-08
kg/kg Total Wet Weight
Calcium
water
4.16E-02
kg/kg Total Wet Weight
Chloride
water
4.11E+00
kg/kg Total Wet Weight
Chromium
water
4.48E-06
kg/kg Total Wet Weight
Cobalt
water
4.00E-08
kg/kg Total Wet Weight
Copper
water
2.00E-04
kg/kg Total Wet Weight
Fluoride
water
2.08E-03
kg/kg Total Wet Weight
Iron
water
4.00E-05
kg/kg Total Wet Weight
Lead
water
1.20E-06
kg/kg Total Wet Weight
Magnesium
water
2.56E-05
kg/kg Total Wet Weight
Manganese
water
6.40E-07
kg/kg Total Wet Weight
Mercury
water
1.35E-07
kg/kg Total Wet Weight
Molybdenum
water
7.20E-05
kg/kg Total Wet Weight
Nickel
water
1.68E-06
kg/kg Total Wet Weight
Selenium
water
1.12E-06
kg/kg Total Wet Weight
Silicon
water
2.40E-04
kg/kg Total Wet Weight
Zinc
water
2.56E-06
kg/kg Total Wet Weight
The Danish Environmental Protection Agency / LCA of grocery carrier bags
103
Table A18. Material and energy requirements and corresponding Ecoinvent processes
used for the modelling of the treatment of fly ashes. Values for material and energy
requirements were obtained from Astrup (2008).
Ecoinvent process name (v 3.4, consequential)
Amount
Unit
market for calcium carbonate, precipitated; GLO
-0.035
kg/kg Total Wet Weight
market group for electricity, high voltage; RER
0.013
kWh/kg Total Wet Weight
market group for diesel; RER
0.0006
kg/kg Total Wet Weight
Table A19. Emissions from treatment of fly ashes. (Astrup, 2008).
Elementary exchange
Compartment
Sub compartment
Amount
Unit
Per
Cadmium, ion
water
surface water
3.10E-09 kg
kg Total Wet Weight
Chloride
water
surface water
0.0092
kg
kg Total Wet Weight
Lead
water
surface water
3.10E-10 kg
kg Total Wet Weight
Mercury
water
surface water
6.10E-11 kg
kg Total Wet Weight
Nickel, ion
water
surface water
1.50E-09 kg
kg Total Wet Weight
Sulfate
water
surface water
0.00082
kg
kg Total Wet Weight
Thallium
water
surface water
4.10E-10 kg
kg Total Wet Weight
Zinc, ion
water
surface water
1.40E-08 kg
kg Total Wet Weight
Table A20. Bottom ashes treatment was assumed to occur in a mineral landfill.
Ecoinvent process name (v 3.4, consequential)
Amount Unit
process-specific burdens, slag landfill; Europe without Switzerland 1
kg/kg Total Wet Weight
Table A21. Sorting efficiency for recyclables. This sorting plant is assumed to operate
in Denmark. COWI (2017)
Carrier bag material
Scenarios
Sorted (%)
Residues (%)
LDPEAVG, LDPEs, LDPEh,
LDPE
70
30 (to incineration in DK)
LDPErec
PP
PP, PPwov
70
30 (to incineration in DK)
Recycled PET
PETREC
70
30 (to incineration in DK)
Polyester
PETPOL
70
30 (to incineration in DK)
Paper
PAP, PAPB
70
30 (to incineration in DK)
Table A22. Material and energy requirements, sorting plant for recyclables in Denmark.
COWI (2017).
Ecoinvent process name (v 3.4, consequential)
Amount
Unit
Marginal electricity, see Appendix B
0.00982
kWh/kg Total Wet Weight
Marginal heat, see Appendix B
0.0189
MJ/kg Total Wet Weight
104 T
he Danish Environmental Protection Agency / LCA of grocery carrier bags
Table A23. Sorting efficiency of recyclables, at recycling plant. COWI (2017).
Carrier bag material
Scenarios
Sorted (%)
Residues (%)
Reference
LDPEAVG, LDPEs,
LDPE
90.3
9.7 (to incineration in EU) Replast A/S (2000)
LDPEh, LDPErec
PP
PP, PPwov
90.3
9.7 (to incineration in EU) Replast A/S (2000)
24.5 (to incineration in
Recycled PET
PETREC
75.5
Giugliano et al. (2011)
EU)
24.5 (to incineration in
Polyester
PETPOL
75.5
Giugliano et al. (2011)
EU)
Paper
PAP, PAPB
91
9 (to incineration in EU) Skjern Papirfabrik (2005)
Table A24. Material and energy requirements, LDPE recycling (Schmidt and Strömberg,
2006).
Ecoinvent process name (v 3.4, consequential)
Amount
Unit
market group for electricity, high voltage; RER
0.76
kWh/kg Total Wet Weight
market group for tap water; RER
2.6
kg/kg Total Wet Weight
market group for diesel; RER
0.00047
kg/kg Total Wet Weight
steam production, in chemical industry; RER
0.32
kg/kg Total Wet Weight
polyethylene production, low density, granulate; RER
-0.9
kg/kg Total Wet Weight recycled
Table A25. Ecoinvent process used to model end-of-life of LDPE residues from the re-
cycling process.
Ecoinvent process name (v 3.4, consequential)
Amount Unit
treatment of waste polyethylene, municipal incineration; Europe without Switzerland 1
kg/kg Total Wet Weight
Table A26. Material and energy requirements, PP recycling (Schmidt and Strömberg,
2006).
Ecoinvent process name (v 3.4, consequential)
Amount
Unit
market group for electricity, high voltage; RER
0.76
kWh/kg Total Wet Weight
market group for tap water; RER
2.6
kg/kg Total Wet Weight
market group for diesel; RER
0.00047
kg/kg Total Wet Weight
steam production, in chemical industry; RER
0.89/2.75
kg/kg Total Wet Weight
polypropylene production, granulate; RER
-0.9
kg/kg Total Wet Weight recycled
Table A27. Ecoinvent process used to model end-of-life of PP residues from the recy-
cling process.
Ecoinvent process name (v 3.4, consequential)
Amount
Unit
treatment of waste polypropylene, municipal incineration; CH
1
kg/kg Total Wet Weight
The Danish Environmental Protection Agency / LCA of grocery carrier bags
105
Table A28. Material and energy requirements, PET recycling (Rigamonti et al., 2014).
The same process was used for polyester.
Amou
Ecoinvent process name (v 3.4, consequential)
Unit
nt
market group for electricity, high voltage; RER
0.32
kWh/kg Total Wet Weight recycled
market group for tap water; RER
2.96
kg/kg Total Wet Weight recycled
market for sodium hydroxide, without water, in 50%
0.003
kg/kg Total Wet Weight recycled
solution state; GLO
steam production, in chemical industry; RER
0.93
kg/kg Total Wet Weight recycled
polyethylene terephthalate production, granulate,
-0.81
kg/kg Total Wet Weight recycled
amorphous, recycled; Europe without Switzerland
Table A29. Ecoinvent process used to model end-of-life of PET residues from the recy-
cling process. The same process was used for polyester.
Ecoinvent process name (v 3.4, con-
Amount
Unit
sequential)
treatment of waste polyethylene terephta-
late, municipal incineration; Europe with-
1
kg/kg Total Wet Weight
out Switzerland
Table A30. Material and energy requirements, paper recycling to cardboard Skjern Pa-
pirfabrik (2005).
External process name
Amount Unit
market group for electricity, high voltage; RER
1.5
kWh/kg Total Wet Weight
market group for tap water; RER
17
kg/kg Total Wet Weight
natural gas, from high pressure network (1-5 bar), at service station; CH 0.069
kg/kg Total Wet Weight
linerboard production, kraftliner; RER
-0.9
kg/kg Total Wet Weight
Table A31. Emissions to the environment, paper recycling to cardboard Skjern Papirf-
abrik (2005).
Elementary exchange
Compartment Sub compartment Amount Unit Per
Nitrogen oxides
air
unspecified
8.80E-05 kg
kg Total Wet Weight
Carbon dioxide, fossil
air
unspecified
0.18
kg
kg Total Wet Weight
Sulfur dioxide
air
unspecified
0.0001
kg
kg Total Wet Weight
COD, Chemical Oxygen Demand
water
surface water
0.0011
kg
kg Total Wet Weight
Nitrogen
water
surface water
6.00E-05 kg
kg Total Wet Weight
Phosphate
water
surface water
2.50E-06 kg
kg Total Wet Weight
Suspended solids, unspecified
water
surface water
0.00016 kg
kg Total Wet Weight
Particulates, > 2.5 um, and < 10um air
unspecified
2.80E-05 kg
kg Total Wet Weight
Table A32. Ecoinvent process used to model end-of-life of paper residues from the re-
cycling process.
Ecoinvent process name (v 3.4, consequential)
Amount Unit
treatment of waste paperboard, municipal incineration; Europe without Switzerland (kg) 1
kg/kg Total Wet Weight
106 T
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The Danish Environmental Protection Agency / LCA of grocery carrier bags
107
Appendix B.
Marginal
technologies
This Section summarizes the technological processes that have been selected as marginal
technologies for the present LCA study. “Marginal technologies” are the technologies that are
assumed to be displaced by the additional functionalities provided by the functional unit. A
classic example for LCAs of waste management systems is the energy produced during the
treatment of waste by incineration. The energy produced represents an additional function,
and electricity and heat produced are used in the energy system instead of producing primary
energy from other sources.
For the present studies, marginal technologies needed to be identified for the energy recov-
ered during incineration in Denmark and for the secondary material produced from the recy-
cling processes. The following subsections present the processes and datasets chosen. In
order to facilitate reading, the selected processes are also provided with their LCIA results
according to the same references provided in Table 5 in the report. In addition, in order to
provide results in the same figures, we have used the following normalization references.
Table B1. Normalization references for the impact categories in Table 5. The Normaliza-
tion references are from the Prosuite project which was developed specifically for the
recommended ILCD method (Laurent et al., 2013), excluded the long-term compartment.
The impact category “Depletion of abiotic resources” respects ILCD recommended
characterization factors
Impact Category
Acronyms Normalization references Units
Climate change
CC
8.10E+03
PE/year
Ozone depletion
OD
4.14E-02
PE/year
Human toxicity, cancer effects
HTc
5.42E-05
PE/year
Human toxicity, non-cancer effects
HTnc
1.10E-03
PE/year
Particulate matter/Respiratory inorganics
PM
2.76E+00
PE/year
Ionizing radiation, human health
IR
1.33E+03
PE/year
Photochemical ozone formation, human health
POF
5.67E+01
PE/year
Terrestrial acidification
TA
4.96E+01
PE/year
Eutrophication terrestrial
TE
1.15E+02
PE/year
Eutrophication freshwater
FE
6.20E-01
PE/year
Eutrophication marine
ME
9.38E+00
PE/year
Ecotoxicity freshwater
ET
6.65E+02
PE/year
Resources, depletion of abiotic resources, fossil
RDfos
6.24E+04
PE/year
Resources, depletion of abiotic resources (reserve base) RD
0.0343
PE/year
108 T
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Appendix B.1
Marginal energy technologies
Electricity
In accordance with the Danish Environmental Protection Agency, the marginal energy tech-
nologies used for this project were based on the latest published project from the Danish Envi-
ronmental Protection Agency, which provided marginal energy technologies for electricity and
heat: TemaNord 2016:537 - Gaining benefits from discarded textiles - LCA of different treat-
ment pathways, published by the Nordic Council of Ministers (Schmidt et al., 2016).
In this project, the long-term marginal was defined as capacity growth over a defined period
(2020-2030). The marginal was provided as a mix of contributing resources, as shown in Table
B2. The electricity marginal mix was then composed of electricity production from single-
technology processes from the Ecoinvent v3.4 database, consequential version. The normal-
ized results of the created process for electricity were compared to those of the electricity
market, high voltage, for Denmark in Ecoinvent v3.4, consequential and found compliant (Fig-
ure B1).
Table B2. Marginal mix, electricity, TemaNord 2016:537
Resource
Percent contribution (%)
Ecoinvent v3.4 process
Biomass
49.8
Electricity production, wood, future; GLO (kWh), consequential
Gas
18.6
Electricity production, natural gas, 10MW; CH, (kWh), consequential
Wind
31.6
Electricity production, wind, <1MW turbine, onshore; DK (kWh), consequential
1.80E-04
1.60E-04
1.40E-04
1.20E-04
1.00E-04
8.00E-05
6.00E-05
4.00E-05
2.00E-05
0.00E+00
CC
OD
HTC
HTNC
PM
IR
POF
TA
TE
FE
ME
ET
RD fos
RD
-2.00E-05
Marginal electricity mix, TemaNord 2016:537, single technologies from Ecoinvent v3.4, consequential
Market for electricity, high voltage; DK, Ecoinvent v3.4, consequential
Figure B1. Marginal electricity mix normalized results, obtained from single technology
dataset from Ecoinvent v3.4, consequential, according to the percent contribution iden-
tified in TemaNord 2016:537, compared to the normalized results of the market for elec-
tricity process, retrieved from Ecoinvent v3.4, consequential.
The Danish Environmental Protection Agency / LCA of grocery carrier bags
109
Heat
In the TemaNord 2016:537 project the marginal technology from heat was chosen based on
the project Miljøprojekt 1458 (Bang Jensen et al., 2013). The contribution of resources to the
marginal heat mix is provided in Table B3. In Miljøprojekt 1458 it was assumed that waste heat
could not replace waste heat, therefore heat from incineration is not part of the heat marginal
mix. The Ecoinvent 3.4 processes used to compose the dataset are specified in Table B3. For
all processes, the selection involved finding heat production datasets from single technologies
and comparing the normalized results of many single-technologies for heat production of the
same type. Due to high differences between the normalized results and to the unavailability of
single technologies datasets for biogas, we selected a process from the allocation at the point
of substitution database instead of the consequential one. The differences in the overall nor-
malized result are minor, due to the minor contribution of biogas. Figure B2 provides a contri-
bution analysis of the single technologies composing the dataset.
Table B2. Marginal mix, electricity, Miljøprojekt 1458
Resource
Percent cont-
Ecoinvent v3.4 process
ribution (%)
Biomass
39 Heat production, hardwood chips from forest, at furnace 5000kW, state-of-the-art
2014; CH (MJ), consequential
Gas
26 Heat production, natural gas, at boiler modulating >100kW; Europe without Switzer-
land (MJ), consequential
Coal
20 Heat production, at hard coal industrial furnace 1-10MW; Europe without Switzer-
land (MJ), consequential
Oil
9 Heat production, heavy fuel oil, at industrial furnace 1MW; CH (MJ), consequential
Biogas
6 Heat and power co-generation, biogas, gas engine; DK (MJ), allocation at the point
of substitution
3.50E-05
3.00E-05
APOS, heat and power co-generation,
biogas, gas engine; DK APOS, Ecoinvent
3.4
2.50E-05
CON, heat production, heavy fuel oil, at
industrial furnace 1MW; CH CON,
2.00E-05
Ecoinvent 3.4
CON, heat production, at hard coal
industrial furnace 1-10MW; Europe
1.50E-05
without Switzerland CON, Ecoinvent 3.4
CON, heat production, natural gas, at
boiler modulating >100kW; Europe without
1.00E-05
Switzerland CON, Ecoinvent 3.4
CON, heat production, hardwood chips
from forest, at furnace 5000kW, state-of-
5.00E-06
the-art 2014; CH CON, Ecoinvent 3.4
0.00E+00
Figure B2. Normalized results and contribution analysis associated with the marginal
heat technology (mix) selected for the present LCA study.
110 T
he Danish Environmental Protection Agency / LCA of grocery carrier bags
Appendix B.2
Marginal materials
The following Table B4 provides a summary of the datasets selected for the production of
materials and for the recycling (for the carrier bags for which it was considered possible). All
datasets were retrieved from Ecoinvent 3.4, consequential version.
Each dataset was selected after comparison of many datasets for the production of the same
material. The criterion for selection of the dataset was general compliance in results with da-
tasets for the same function, and availability of the dataset. For production, market datasets
were always selected (if available), since market comprises production shares globally and
average transport distances. For substitution, we selected simply the production in a specific
geographical area (preferably Europe, since it is where the recycling process is assumed to
occur).
For recycled LDPE, there was no available dataset on the production. Therefore, the LCA was
carried out considering the same production as virgin LDPE. The results obtained are as-
sumed to be conservative, since the impacts connected to virgin plastics are usually larger
than the ones of recycled plastics, as it is shown in Figure B3 for PET, for both datasets are
available in Ecoinvent v3.4, consequential.
Table B4. Summary of datasets used as production of materials and for the materials
substituted by the secondary material produced from the recycling processes.
Material
Production
Substitution
Market for polyethylene, low density,
Polyethylene production, low density,
LDPE
granulate; GLO (kg)
granulate; RER (kg)
Market for polyethylene, low density,
Polyethylene production, low density,
Recycled LDPE
granulate; GLO (kg)
granulate; RER (kg)
Market for polypropylene, granulate;
Polypropylene production, granulate;
PP
GLO (kg)
RER (kg)
Market for polyethylene terephthalate,
Polyethylene terephthalate produc-
Recycled PET
granulate, amorphous, recycled; RoW
tion, granulate, amorphous, recycled;
(kg)
Europe without Switzerland (kg)
Market for polyethylene terephthalate,
Polyethylene terephthalate produc-
Polyester
granulate, amorphous; GLO (kg)
tion, granulate, amorphous; RER (kg)
Market for polyester-complexed starch
Starch-complexed biopolymer
-
biopolymer; GLO (kg)
Kraft paper production, unbleached;
Linerboard production, kraftliner; RER
Unbleached paper
RER (kg)
(kg)
Kraft paper production, bleached; RER
Linerboard production, kraftliner; RER
Bleached paper
(kg)
(kg)
Market for textile, woven cotton; GLO
(kg)
Cotton organic
-
Minus “CON, market for nitrogen fertilis-
er, as N; GLO (kg)”
Market for textile, woven cotton; GLO
Cotton conventional
-
(kg)
Jute
Market for textile, jute; GLO (kg)
-
Packaging film production, low density
LDPE bin bag
-
polyethylene; RER (kg)
The Danish Environmental Protection Agency / LCA of grocery carrier bags
111
0.0045
0.004
0.0035
0.003
0.0025
PE
0.002
0.0015
0.001
0.0005
0
CC
OD
HTC
HTNC
PM
IR
POF
TA
TE
FE
ME
ET
RD fos
RD
Market for polyethylene terephthalate, granulate, amorphous; GLO
Polyethylene terephthalate production, granulate, amorphous, recycled; RoW
Figure B3. Normalized impact scores for virgin and recycled PET production.
112 T
he Danish Environmental Protection Agency / LCA of grocery carrier bags
The Danish Environmental Protection Agency / LCA of grocery carrier bags
113
Appendix C.
Additional
results
This Section reports the primary reuse times calculated for all impact categories, which were
omitted from the main report for brevity.
Tables C1-C14 provide the calculated number of primary reuse times for each carrier bag in
comparison to the reference bag LDPEavg, for each impact category. Table C15 provides a
minimum – maximum range obtained with the calculated number of primary reuse times for
each impact category. Table C16 provides the minimum-maximum range without the ozone
depletion impact category, which provided high result scores affecting the cotton and compo-
site bags. Table C17 provides the average number of reuse times obtained averaging results
across all impact categories. Results in Tables C15, C16 and C17 are rounded.
Table C1. Calculated number of primary reuse times for the carrier bags in the rows,
associated to the disposal options in the columns, necessary to provide the same envi-
ronmental performance of the average LDPE carrier bag, reused as a waste bin bag
before incineration (EOL3), for the ozone depletion impact category
LDPEavg, EOL3
Ozone Depletion
EOL1
EOL2
EOL3
LDPEavg
-0.2
2.9
0.0
LDPEs
0.2
4.8
0.5
LDPEh
0.0
3.7
0.2
LDPErec
0.9
7.3
1.2
PP
34.5
52.0
34.7
PPwov
29.7
44.9
30.0
PETrec
44.3
60.3
44.7
PETpol
14.3
18.6
14.6
BP
9.4
-
9.7
PAP
7.6
12.0
7.9
PAPb
17.9
22.4
18.2
COTorg
19961.8
-
19962.3
COT
7069.0
-
7069.2
COM
874.1
-
874.3
114 T
he Danish Environmental Protection Agency / LCA of grocery carrier bags
Table C2. Calculated number of primary reuse times for the carrier bags in the rows,
associated to the disposal options in the columns, necessary to provide the same envi-
ronmental performance of the average LDPE carrier bag, reused as a waste bin bag
before incineration (EOL3), for the human toxicity, cancer effects impact category
LDPEavg, EOL3
Human toxicity, cancer
EOL1
EOL2
EOL3
LDPEavg
0.2
0.1
0.0
LDPEs
0.7
0.7
0.4
LDPEh
0.4
0.4
0.2
LDPErec
1.4
1.4
1.1
PP
1.3
1.8
1.0
PPwov
1.0
1.5
0.7
PETrec
5.1
4.6
4.8
PETpol
1.1
0.7
0.9
BP
1.0
-
0.7
PAP
0.3
0.5
-0.1
PAPb
0.4
0.6
0.1
COTorg
424.5
-
424.0
COT
149.6
-
149.4
COM
36.8
-
36.6
Table C3. Calculated number of primary reuse times for the carrier bags in the rows,
associated to the disposal options in the columns, necessary to provide the same envi-
ronmental performance of the average LDPE carrier bag, reused as a waste bin bag
before incineration (EOL3), for the human toxicity, non-cancer effects impact category
LDPEavg, EOL3
Human toxicity, non-cancer
EOL1
EOL2
EOL3
LDPEavg
-0.6
0.9
0.0
LDPEs
-1.3
0.9
-0.3
LDPEh
-0.9
0.9
-0.3
LDPErec
-2.2
0.9
-1.1
PP
-6.6
2.6
-5.9
PPwov
-5.6
2.4
-4.7
PETrec
-1.3
5.2
-0.2
PETpol
0.3
2.3
1.1
BP
5.4
-
6.5
PAP
13.5
14.6
14.7
PAPb10
13.5
14.6
14.7
COTorg
230.1
-
231.8
COT
80.3
-
81.2
COM
-24.5
-
-23.9
10 The highest value for bleached paper was increased to be equal to the value for unbleached paper
The Danish Environmental Protection Agency / LCA of grocery carrier bags
115
116 T
he Danish Environmental Protection Agency / LCA of grocery carrier bags
Table C4. Calculated number of primary reuse times for the carrier bags in the rows,
associated to the disposal options in the columns, necessary to provide the same envi-
ronmental performance of the average LDPE carrier bag, reused as a waste bin bag
before incineration (EOL3), for the particulate matter impact category
LDPEavg, EOL3
Particulate matter
EOL1
EOL2
EOL3
LDPEavg
0.6
2.1
0.0
LDPEs
1.4
3.6
0.3
LDPEh
1.0
2.7
0.3
LDPErec
2.7
5.7
1.4
PP
10.2
21.2
9.4
PPwov
8.7
18.2
7.7
PETrec
26.7
32.8
25.5
PETpol
9.1
10.5
8.2
BP
11.1
-
9.9
PAP
16.6
25.3
15.3
PAPb
28.6
37.2
27.4
COTorg
1119.8
-
1118.0
COT
394.6
-
393.7
COM
300.1
-
299.3
Table C5. Calculated number of primary reuse times for the carrier bags in the rows,
associated to the disposal options in the columns, necessary to provide the same envi-
ronmental performance of the average LDPE carrier bag, reused as a waste bin bag
before incineration (EOL3), for the ionizing radiation impact category
LDPEavg, EOL3
Ionising radiation
EOL1
EOL2
EOL3
LDPEavg
0.4
3.2
0.0
LDPEs
1.1
5.1
0.4
LDPEh
0.7
4.0
0.2
LDPErec
2.1
7.7
1.3
PP
19.8
35.8
19.3
PPwov
17.0
30.8
16.3
PETrec
32.1
40.6
31.3
PETpol
9.9
12.2
9.3
BP
8.2
-
7.3
PAP
13.8
18.4
12.9
PAPb11
13.8
18.4
12.9
COTorg
906.7
-
905.4
COT
321.9
-
321.3
COM
95.5
-
95.0
11 The highest value for bleached paper was increased to be equal to the value for unbleached paper
The Danish Environmental Protection Agency / LCA of grocery carrier bags
117
Table C6. Calculated number of primary reuse times for the carrier bags in the rows,
associated to the disposal options in the columns, necessary to provide the same envi-
ronmental performance of the average LDPE carrier bag, reused as a waste bin bag
before incineration (EOL3), for the human toxicity, photochemical ozone formation im-
pact category
LDPEavg, EOL3
Photochemical ozone formation
EOL1
EOL2
EOL3
LDPEavg
0.5
0.4
0.0
LDPEs
1.3
1.0
0.3
LDPEh
0.9
0.6
0.3
LDPErec
2.2
1.9
1.2
PP
6.4
6.8
5.6
PPwov
5.4
5.7
4.5
PETrec
6.6
8.2
5.5
PETpol
1.6
1.9
0.9
BP
1.7
-
0.6
PAP
1.7
2.5
0.6
PAPb
2.7
3.4
1.7
COTorg
194.7
-
193.2
COT
68.0
-
67.2
COM
36.8
-
36.1
Table C7. Calculated number of primary reuse times for the carrier bags in the rows,
associated to the disposal options in the columns, necessary to provide the same envi-
ronmental performance of the average LDPE carrier bag, reused as a waste bin bag
before incineration (EOL3), for the terrestrial acidification impact category
LDPEavg, EOL3
Terrestrial acidification
EOL1
EOL2
EOL3
LDPEavg
0.5
1.3
0.0
LDPEs
1.2
2.4
0.4
LDPEh
0.8
1.7
0.2
LDPErec
2.3
3.9
1.3
PP
6.7
15.0
6.0
PPwov
5.7
12.8
4.8
PETrec
13.6
20.0
12.6
PETpol
4.3
5.8
3.6
BP
8.8
-
7.8
PAP
4.7
7.7
3.6
PAPb
6.8
9.8
5.9
COTorg
756.5
-
755.1
COT
265.5
-
264.8
COM
142.7
-
142.1
118 T
he Danish Environmental Protection Agency / LCA of grocery carrier bags
Table C8. Calculated number of primary reuse times for the carrier bags in the rows,
associated to the disposal options in the columns, necessary to provide the same envi-
ronmental performance of the average LDPE carrier bag, reused as a waste bin bag
before incineration (EOL3), for the terrestrial eutrophication impact category
LDPEavg, EOL3
Terrestrial eutrophication
EOL1
EOL2
EOL3
LDPEavg
0.9
5.0
0.0
LDPEs
1.8
7.8
0.3
LDPEh
1.3
6.1
0.3
LDPErec
3.4
11.7
1.6
PP
19.9
50.7
18.7
PPwov
17.1
43.8
15.6
PETrec
39.9
66.8
38.2
PETpol
14.1
21.3
12.8
BP
28.7
-
26.9
PAP
23.4
34.0
21.6
PAPb
30.0
40.6
28.4
COTorg
3007.7
-
3005.1
COT
1058.5
-
1057.2
COM
740.2
-
739.1
Table C9. Calculated number of primary reuse times for the carrier bags in the rows,
associated to the disposal options in the columns, necessary to provide the same envi-
ronmental performance of the average LDPE carrier bag, reused as a waste bin bag
before incineration (EOL3), for the freshwater eutrophication impact category
LDPEavg, EOL3
Freshwater eutrophication
EOL1
EOL2
EOL3
LDPEavg
-0.4
2.9
0.0
LDPEs
-1.0
3.9
-0.4
LDPEh
-0.7
3.3
-0.2
LDPErec
-1.1
5.7
-0.4
PP
29.0
46.6
29.5
PPwov
25.2
40.5
25.9
PETrec
95.3
84.0
96.0
PETpol
34.6
27.7
35.1
BP
41.0
-
41.8
PAP
42.2
44.1
43.0
PAPb12
42.2
44.1
43.0
COTorg
3325.3
-
3326.4
COT
1177.8
-
1178.3
COM
592.2
-
592.6
12 The highest value for bleached paper was increased to be equal to the value for unbleached paper
The Danish Environmental Protection Agency / LCA of grocery carrier bags
119
120 T
he Danish Environmental Protection Agency / LCA of grocery carrier bags
Table C10. Calculated number of primary reuse times for the carrier bags in the rows,
associated to the disposal options in the columns, necessary to provide the same envi-
ronmental performance of the average LDPE carrier bag, reused as a waste bin bag
before incineration (EOL3), for the marine eutrophication impact category
LDPEavg, EOL3
Marine eutrophication
EOL1
EOL2
EOL3
LDPEavg
0.5
1.1
0.0
LDPEs
1.2
2.1
0.4
LDPEh
0.8
1.5
0.2
LDPErec
2.2
3.5
1.3
PP
10.5
15.9
9.9
PPwov
9.0
13.6
8.2
PETrec
13.0
18.6
12.1
PETpol
4.7
5.9
4.0
BP
14.2
-
13.2
PAP
7.8
9.1
6.8
PAPb
10.0
11.4
9.2
COTorg
625.1
-
623.7
COT
220.0
-
219.3
COM
161.3
-
160.8
Table C11. Calculated number of primary reuse times for the carrier bags in the rows,
associated to the disposal options in the columns, necessary to provide the same envi-
ronmental performance of the average LDPE carrier bag, reused as a waste bin bag
before incineration (EOL3), for the freshwater ecotoxicity impact category
LDPEavg, EOL3
Freshwater ecotoxicity
EOL1
EOL2
EOL3
LDPEavg
0.4
0.8
0.0
LDPEs
1.0
1.6
0.4
LDPEh
0.7
1.1
0.2
LDPErec
1.9
2.7
1.2
PP
4.2
6.8
3.7
PPwov
3.5
5.8
2.9
PETrec
8.9
15.8
8.2
PETpol
2.3
4.5
1.8
BP
1.6
-
0.8
PAP
2.9
4.0
2.1
PAPb13
2.9
4.0
2.1
COTorg
633.5
-
632.4
COT
224.5
-
223.9
COM
84.0
-
83.6
13 The highest value for bleached paper was increased to be equal to the value for unbleached paper
The Danish Environmental Protection Agency / LCA of grocery carrier bags
121
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he Danish Environmental Protection Agency / LCA of grocery carrier bags
Table C12. Calculated number of primary reuse times for the carrier bags in the rows,
associated to the disposal options in the columns, necessary to provide the same envi-
ronmental performance of the average LDPE carrier bag, reused as a waste bin bag
before incineration (EOL3), for the resource depletion, fossil impact category
LDPEavg, EOL3
Resource depletion, fossil
EOL1
EOL2
EOL3
LDPEavg
0.6
0.2
0.0
LDPEs
1.3
0.8
0.3
LDPEh
0.9
0.5
0.3
LDPErec
2.3
1.6
1.2
PP
8.7
7.3
7.9
PPwov
7.4
6.2
6.5
PETrec
9.9
9.8
8.8
PETpol
2.8
2.3
2.0
BP
1.7
-
0.6
PAP
0.1
1.1
-1.0
PAPb
2.3
3.3
1.4
COTorg
185.9
-
184.3
COT
65.2
-
64.4
COM
26.0
-
25.3
Table C13. Calculated number of primary reuse times for the carrier bags in the rows,
associated to the disposal options in the columns, necessary to provide the same envi-
ronmental performance of the average LDPE carrier bag, reused as a waste bin bag
before incineration (EOL3), for the resource depletion, abiotic impact category
LDPEavg, EOL3
Resource depletion
EOL1
EOL2
EOL3
LDPEavg
0.2
0.3
0.0
LDPEs
0.7
1.0
0.4
LDPEh
0.4
0.6
0.2
LDPErec
1.4
1.8
1.1
PP
0.5
1.6
0.2
PPwov
0.3
1.2
0.0
PETrec
12.2
9.6
11.8
PETpol
3.6
2.3
3.3
BP
2.2
-
1.9
PAP
22.7
22.5
22.4
PAPb14
22.7
22.5
22.4
COTorg
278.2
-
277.7
COT
98.0
-
97.8
COM
19.2
-
19.0
14 The highest value for bleached paper was increased to be equal to the value for unbleached paper
The Danish Environmental Protection Agency / LCA of grocery carrier bags
123
124 T
he Danish Environmental Protection Agency / LCA of grocery carrier bags
Table C14. Calculated number of primary reuse times for the carrier bags in the rows,
associated to the disposal options in the columns, necessary to provide the same envi-
ronmental performance of the average LDPE carrier bag, reused as a waste bin bag
before incineration (EOL3), for the water resource depletion impact category
LDPEavg, EOL3
Water use
EOL1
EOL2
EOL3
LDPEavg
1.2
3.3
0.0
LDPEs
2.3
5.4
-0.2
LDPEh
1.7
4.2
-3.9
LDPErec
1.7
3.8
0.5
PP
38.4
51.3
37.2
PPwov
33.1
44.3
31.9
PETrec
69.7
66.2
68.5
PETpol
22.9
19.7
21.6
BP
0.1
-
-2.3
PAP
16.1
77.2
13.6
PAPb15
16.1
77.2
13.6
COTorg
3832.8
-
3830.4
COT
1359.3
-
1358.1
COM
276.5
-
275.3
Table C15. Calculated number of primary reuse times for the carrier bags in the rows,
associated to the disposal options in the columns, necessary to provide the same envi-
ronmental performance of the average LDPE carrier bag, reused as a waste bin bag
before incineration (EOL3). The Table shows a (min, max) range obtained considering
the minimum and maximum number calculated for each bag for all impact categories.
Numbers lower than zero indicate when the carrier bag in the row already provides a
better performance than the LDPEavg reference bag.
LDPEavg, EOL3
Min - Max ranges, all impact categories
EOL1
EOL2
EOL3
LDPEavg
(-1, 1)
(0, 5)
(0, 0)
LDPEs
(-1, 2)
(1, 8)
(0, 1)
LDPEh
(-1, 2)
(0, 6)
(-4, 0)
LDPErec
(-2, 3)
(1, 12)
(-1, 2)
PP
(-7, 38)
(2, 52)
(-6, 37)
PPwov
(-6, 33)
(1, 45)
(-5, 32)
PETrec
(-1, 95)
(5, 84)
(0, 96)
PETpol
(0, 35)
(1, 28)
(1, 35)
BP
(0, 41)
-
(-2, 42)
PAP
(0, 42)
(0, 77)
(-1, 43)
PAPb16
(0, 42)
(1, 77)
(0, 43)
15 The highest value for bleached paper was increased to be equal to the value for unbleached paper
16 The highest value for bleached paper was increased to be equal to the value for unbleached paper
The Danish Environmental Protection Agency / LCA of grocery carrier bags
125
COTorg
(150, 20000)
-
(150, 20000)
COT
(50, 7100)
-
(50, 7100)
COM
(-20, 870)
-
(-20, 870)
Table C16. Calculated number of primary reuse times for the carrier bags in the rows,
associated to the disposal options in the columns, necessary to provide the same envi-
ronmental performance of the average LDPE carrier bag, reused as a waste bin bag
before incineration (EOL3). The Table shows a (min, max) range obtained considering
the minimum and maximum number calculated for each bag for all impact categories,
without ozone depletion. Numbers lower than zero indicate when the carrier bag in the
row already provides a better performance than the LDPEavg reference bag.
LDPEavg, EOL3
Min - Max ranges, all impact categories w/o ozone depletion
EOL1
EOL2
EOL3
LDPEavg
(-1, 1)
(0, 5)
(0, 0)
LDPEs
(-1, 2)
(1, 8)
(0, 0)
LDPEh
(-1, 2)
(0, 6)
(-4, 0)
LDPErec
(-2, 3)
(1, 12)
(-1, 2)
PP
(-7, 38)
(2, 51)
(-6, 37)
PPwov
(-6, 33)
(1, 44)
(-5, 32)
PETrec
(-1, 95)
(5, 84)
(0, 96)
PETpol
(0, 35)
(1, 28)
(1, 35)
BP
(0, 41)
-
(-2, 42)
PAP
(0, 42)
(0, 77)
(-1, 43)
PAPb
(0, 30)
(1, 72)
(0, 28)
COTorg
(150, 3800)
-
(150, 3800)
COT
(50, 1400)
-
(50, 1400)
COM
(-20, 740)
-
(-20, 740)
Table C17. Average number of primary reuse times for the carrier bags in the rows,
associated to the disposal options in the columns, necessary to provide the same envi-
ronmental performance of the average LDPE carrier bag, reused as a waste bin bag
before incineration (EOL3). The average number was obtained averaging the results of
the carrier bags in the rows for each impact category.
LDPEavg, EOL3
Average number of reuse times
EOL1
EOL2
EOL3
LDPEavg
0
2
0
LDPEs
1
3
0
LDPEh
1
2
0
LDPErec
2
4
1
PP
13
21
12
PPwov
11
18
10
PETrec
26
30
25
PETpol
9
9
8
BP
9
-
8
PAP
12
18
11
PAPb
10
16
9
126 T
he Danish Environmental Protection Agency / LCA of grocery carrier bags
COTorg
2376
-
2375
COT
840
-
840
COM
226
-
225
The Danish Environmental Protection Agency / LCA of grocery carrier bags
127
Appendix D.
Critical review
KRITISK REVIEW AF "MILJØMÆSSIGE EFFEKTER AF BRUG AF PLASTBÆREPOSER I
FORHOLD TIL ALTERNATIVE BÆREPOSER"
KRISTISK REVIEW AF LCA UDFØRT AF EKSTERN EKSPERT EFTER ISO 14044
Indledning
Dette kritiske review af livscyklusanalysen "LCA of grocery carrier bags" angående miljøeffek-
terne ved produktion, anvendelse og affaldsbehandling af bæreposer er udført af COWI efter
den internationale standard ISO 14044, så vidt muligt.
Processen for det kritiske review var som følger:
COWI gennemfører første review udført januar 2018.
DTU forholder sig til reviewet og laver eventuelle rettelser (ny version af rap-port) februar
2018
COWI forholder sig til rettelserne (nedenstående afsnit og tabel) i det endelige review notat
februar 2018
Fra COWI blev det kritiske review gennemført af Line Geest Jakobsen og Trine Lund Neidel.
128 T
he Danish Environmental Protection Agency / LCA of grocery carrier bags
Generelle kommentarer
Generelle aspekter
Kommentarer fra COWI, første runde
Svar på kommentarer fra DTU Miljø
Kommentarer fra
COWI, anden runde
Metoderne anvendt er i overensstem-
Ja, i vid udstrækning. DTU har skrevet, at der er
According to our understanding of the ISO 14044 standard (document
√
melse med denne internationale stan-
uoverensstemmelse, idet der ikke er foretaget en
version of 2008, point 6.1), when the results of the LCA are intended to be
dard
udveksling med et ekspertpanel undervejs i projektet. used to support a comparative assertion intended to be disclosed to the
Som vi forstår standarden, kan det kritiske review
public, the review should be conducted by a panel of interested parties.
enten foretages af (1) en ekstern ekspert i slutningen
Therefore, if the present study is going to be disclosed to the public and
af processen, som vi gør her, eller (2) af et interes-
used for decision support, the critical review according to point 6.3 should
sentpanel, der inddrages i løbet af processen.
apply instead of the critical review by external experts (6.2). The critical
review by a panel of interested parties was however not budgeted in the
time constraints of the current study.
Metoderne er videnskabeligt og teknisk Vi mener ikke, at det giver en fair sammenligning, at
Addressed in the report as critical assumptions (Section 3). New results
√
gyldige.
runde antallet af poser, der skal anvendes til at opfyl-
provided as sensitivity analysis (Section 7).
de FU, op. Det er forkert at sammenligne f.eks. 2
We understand the reviewers’ concerns and we have decided to introduce
(kapacitet: 18,8 liter, 10,5 kg) LDPE simple poser med a different way of calculating the reference flow for this LCA study in the
1 LDPE gns. pose (kapacitet 22,4 liter, 12,0 kg). Det
sensitivity analysis, instead of using the reference flow used in the study
er jo ikke bestemt, at alle altid køber præcis det, der
of Edwards and Fry, 2011. We have added a section on critical assump-
kan være i en standard pose. Der vil jo være en stor
tions where we clearly raise the overcapacity concerns of our reference
overkapacitet i de fleste tilfælde, hvor der er valgt at
flow calculation.
anvende 2 reference-poser - hvis man f.eks. handlede In the sensitivity analysis, we re-calculated the reference flows as frac-
44 L/24 kg (dobbelt så meget som FU), vil man jo ikke tions for those bags whose volume and weight holding capacity were
benytte 4 LDPE virgin simple poser (alternativet), da 3 inferior to those of an LDPE carrier bag with average characteristics (for
poser er tilstrækkeligt. Vi mener derfor, at der skal
example, as you suggest, 1.2 carrier bags for simple virgin LDPE instead
sammenlignes med det antal (ikke afrundet) poser der of 2). The carrier bags affected by this reference flow change were virgin
skal anvendes når begge krav (volumen og vægt
LDPE simple, LDPE recycled, biopolymer, paper, and organic cotton. For
kapacitet) er opfyldte. Dette vil betyde, at der f.eks. for these bags, the change of reference flow resulted in a lower magnitude of
The Danish Environmental Protection Agency / LCA of grocery carrier bags
129
“LDPE virgin simple” vil skulle sammenlignes med 1,2 the results.
poser i stedet for 2 (22,4/18,8=1,2).
As far as the overall results are concerned:
the most preferable end-of-life option for each carrier bag was not affected
the bags providing the lowest impacts for each impact category were still
paper, biopolymer and virgin LDPE carrier bags – the best performance
among virgin LDPE carrier bags was provided by simple virgin LDPE bags
the number of reuse times decreased for the bags affected by the refer-
ence flow change. For simple virgin LDPE, recycled LDPE, biopolymer
and paper bags, the calculated number of reuse times was similar to the
previous results. Biopolymer and paper presented lower number of reuse
times across all impact categories. Organic cotton presented a havened
number of reuse times: around 80 times for climate change and more than
10000 for all impact categories.
The results of this sentivity analysis showed that the choice of reference
flow influenced heavily the carrier bag with higher impacts connected to
production and with a lower volume than expressed in the functional unit.
We have added a dedicated section on carrier bag design where we pro-
vided comments on the influence of the design of the carrier bags on the
results.
Anvendte data er hensigtsmæssige og
Hvad menes med polyester. Polyester dækker over
Corrected.
√
fornuftige
flere polymerer, bl.a. PET, så hvad menes med denne We had used a generic polyester production data from Ecoinvent. After
posetype?
your comment, we verified the polymer material of the surveyed polyester
bags, which showed to be virgin PET (We have re-modelled the results for
this carrier bag type using an Ecoinvent production dataset for virgin PET
because a dataset for “polyester PET” was not available. Results have
been updated throughout the report and executive summary.
Uddyb beskrivelsen af biopolymer, linje 555 og frem.
Added (now line 645)
√
Er det en komposterbar pose?
Yes, the bag is a compostable bag. (+ design considerations on effective
compostability)
Vurderingsrapporten er gennemskuelig Det danske resumé har brug for en kritisk gennem-
We have done a full readthrough of the Danish Summary.
√
og konsekvent
læsning ift. sprog. F.eks. står der organisk i stedet for
130 The
Danish Environmental Protection Agency / LCA of grocery carrier bags
økologisk, og ozonforstyrrelse i stedet for ozonned-
brydning.
Småting
Det er svært at huske hvad scenariebetegnelserne
Changed.
√
står for. Kunne man overveje forkortelser, der i højere Please see the new list of abbreviations for the carrier bag scenarios..
grad er forbundet til materialetype?
I resuméerne kan der i linje 120/270 stå de fire LDPE Added.
√
pose typer, der er undersøgt
In the Danish and English summaries, we added a brief description of the
four LDPE carrier bags investigated.
“Low-density polyethylene (LDPE), 4 types: an LDPE carrier bag with
average characteristics, an LDPE carrier bag with soft handle, an LDPE
carrier bag with rigid handle and a recycled LDPE carrier bag.”
Der er forskel i tabellerne IV i de to resumé.
Corrected.
√
Pilen i figur I (dansk resume) fra Produktion af embal- Corrected
√
lage materiale er vendt forkert.
Linje 463 under lightweight plastic carrier bags -
Corrected.
√
skriftstørrelsen er forskellig.
Table 2, linje 600, antal LDPE poser simple og rigid
Corrected.
√
handle adderer ikke til 23.
The numbers erroneously referred to a previous version of the Table,
where there was no distinction between virgin LDPE carrier bags (in total
23) and recycled LDPE carrier bags (in total 3).
Hvorfor står der “no” i table 3, linje 740 for vægt kapa- Corrected.
√
citet for flg. LDPE recycled, rigid handle, biopolymer
Yes, the recycled LDPE carrier bag with rigid handle has a weight holding
og paper - de har en kapacitet på 12 kg?
capacity of 12 kg. The “No” erroneously reported was a typo.
We decided to report the reference flow for simple and rigid handle recy-
cled LDPE carrier bag in Table 3 for completeness, but in the end we
considered only a scenario with a recycled LDPE carrier bag with average
characteristics, due to the low number of recycled LDPE carrier bags
encountered in the survey, and due to the lack of data for recycled LDPE
carrier bag production.
Table 5, linje 816, i “Human toxicity, non-cancer ef-
Corrected.
√
The Danish Environmental Protection Agency / LCA of grocery carrier bags
131
fects” står der CTUh/PE/year - skal der ikke bare stå
The impact assessment unit was in fact CTUh, CTUh/PE/year refers to
CTUh?
the normalized unit, which was not used in the present study and was
erroneously reported in Table 5.
Anvend samme rækkefølge for poserne i alle tabeller. Corrected.
√
Kan der komme et tal efter komma i Figure 16 i y-
Corrected.
√
aksen?
Now Figure 16 provides one digit after the comma.
Kan det i Table 15 indikeres, hvilken påvirkningskate-
Added in the text.
√
gori der giver udslag i det største antal genbrug? I har We added in the discussion of the results that for some carrier bags the
taget "den værste" kategori, men det er væsentligt for number of reuse times was rather homogeneous among impact catego-
tolkningen, at man kan se, om det er generelt
ries, for other carrier bags the number of reuse times was mainly provided
højt/lavt, eller skyldes stor spredning imellem impact
by few or just one impact category (as in the case of organic cotton,
kategorierne (evt. pga. varierende datakvalitet).
where the number of reuse times strongly depends on ozone depletion
results).
This could be related to data (in general, whether it has low quality or not),
but also to the structure of the model (for example, the resulting climate
change score from the interaction of carrier bag material production data,
input specific emissions and energy recovery). For the organic cotton bag,
the ozone depletion results were governed by cotton production data.
Det ville være dejligt med billeder af de forskellige
Provided.
√
posetyper ved beskrivelserne af poserne i afsnit 2, så Photos have been provided in order to complement the description of the
man i højere grad får et indtryk af hvilke poser, der er surveyed carried bags in Section 2. (Figures 1-9). We had initially decided
tale om.
not to include the photos in order not to show the brand names on the
carrier bags. The Miljøstyrelsen agrees with your request, but suggested
to provide examples of the carrier bags instead of photos of the surveyed
carrier bags, which would display the names of the retailers.
132 The
Danish Environmental Protection Agency / LCA of grocery carrier bags
Tjekliste
Følgende skal være dækket af tredjepartsrapporten
Aspekter fra ISO 14044
Kommentarer fra COWI, første runde
Svar på kommentarer fra DTU Miljø
Kommentarer fra CO-
WI, anden runde
Generelle aspekter
livscyklusvurderingens opdragsgiver, udøveren af
√
livscyklusvurderingen
rapportens dato
√
erklæring om, at vurderingen er udført i overens-
√
stemmelse med kravene i ISO 14044
Vurderingens formål
grundene til at foretage vurderingen
√
dens påtænkte anvendelser
√
målgrupperne
√
erklæring om, hvorvidt vurderingen påtænkes at un-
√
derstøtte sammenlignende påstande, som er beregnet
til offentliggørelse
Vurderingens afgrænsning
funktion, herunder
erklæring om ydeevneegenskaber
√
eventuel udeladelse af yderligere funktioner i sam-
√
menligninger
funktionel enhed, herunder
The Danish Environmental Protection Agency / LCA of grocery carrier bags
133
overensstemmelse med formål og afgrænsning
Nej, se nedenfor
definition
Der står intet omkring produktion, distribution og
Corrected.
√
affaldsbehandling.
The functional unit now specifies more details regarding
production, distribution and waste management. Further
details have been added in the text following the functional
unit definition.
“Carrying one time grocery shopping with an average vol-
ume of 22 litres and with an average weight of 12 kilograms
from Danish supermarkets to homes in 2017 with a (newly
purchased) carrier bag. The carrier bag is produced in Eu-
rope and distributed to Danish supermarkets. After use, it is
collected by the Danish waste management system.”
resultat af ydeevnemåling
√
systemgrænse, herunder
udeladelser af livscyklusfaser, processer eller databe- I EoL scenarierne 1 og 3 er der i boksene der star-
Added collection box in Figures 14-16.
√
hov
ter i linje 1008 samt 1029 ikke indtegnet indsamling Yes, collection was included in the study for cardboard
- hvorfor ikke? Det er vel medtaget ikke?
packaging collection and for the collection of the carrier
bags for the different end-of-life scenarios. We have added
more details in Figures 14-16 by specifying “collection” in
the processes. We have provided the same colours as Fi-
gure 13.
kvantificering af energi-og materialeinput og –output
Mht. anvendelse af produktion af jomfruelig LDPE til Added as sensitivity analysis.
√
at repræsentere den genanvendte LDPE; det ser ud The reduced impacts connecetd to LDPE production have
til at der er ret stor forskel for PET, hvilket må for-
lowered the impacts for recycled LDPE carrier bags. LDPE
modes for LDPE også. Jeg vil foreslå at lave en
recycled resulted the carrier bag with the lowest associated
følsomhedsanalyse, hvor man f.eks. anvender 25 % impacts for particulate matter, photochemical ozone for-
mindre udledninger.
mation, terrestrial and freashwater eutrophication. The cal-
culated number of reuse times decreased by 1 unit.
We observed in the discussion of the sensitivity analysis
that the sensitivity performed on the reference flow provided
larger variations in the results for the calculated number of
134 The
Danish Environmental Protection Agency / LCA of grocery carrier bags
reuse times for this type of carrier bag.
Hvorfor er der anvendt forskellig ekstern process for Yes, we have used different external processes for the
√
produktion af LDPE til bæreposen og affaldsposen? production of the bags.
(s. 85)
First of all, for LDPE carrier bags we had some data regard-
ing the production of the carrier bag, for example energy
and materials required per kg of produced carrier bag. For
the waste bin bag, we did not have such data. For this rea-
son, we decided to use the Ecoinvent dataset for the pro-
duction of LDPE packaging, which included extrusion of
LDPE and ancillary materials consumption.
Secondly, the waste bin bags surveyed for this study were
thinner and of a visible lower quality compared to the LDPE
carrier bags. The Ecoinvent process chosen for waste bin
bags production presented slightly lower overall impacts
compared to the modelled one for the production of LDPE
carrier bag. This was considered in line with the intended
use of the bag: the LDPE carrier bags are intended for mul-
tiple uses, while the waste bin bag is intended for single
use.
During the modelling phase, we performed a sensitivity
analysis and modelled the waste bin bag exactly as the
LDPE carrier bag, but according to the mass of the waste
bin bag. The environmental impacts resulted similar to the
chosen Ecoinvent process for waste bin bags.
Finally, selecting a process with slightly lower impacts for
the production of the waste bin bag allows being more con-
servative regarding the results, since lower benefits will
arise from the saving of a waste bin bag.
Burde produktion af komposit-posen ikke bestå af
Yes, the composite bag was modelled as a combination of
√
de andre dele end jute også, PP og bomuld? I har
the three materials: PP, jute and cotton. Based on the sur-
allerede data for disse processer, så der skal bare
vey, we assumed 80% jute, 10% PP and 10% cotton.
en fordeling af de tre materialer til.
This proportion was present in the description of the com-
The Danish Environmental Protection Agency / LCA of grocery carrier bags
135
posite bag scenario in Section 4. We added these details
also in the assumptions section.
Er der i produktion af biopolymer medtaget karbon-
No, to our understanding the Ecoinvent dataset for the pro-
√
lagring?
duction of starch-complexed biopolymer does not take into
account carbon storage.
We added this detail in the description of the biopolymer
carrier bag scenario, Section 4.
Antagelsen om, at der er det samme tab i sortering We did not have actual data for recovery efficiencies and
√
før genanvendelse for jomfruelig LDPE og genan-
residues occurring during recycling for recycled polymers,
vendt LDPE i genanvendelsesprocessen kan disku- we only had data for recycling of virgin polymers. Therefore,
teres (linje 1065). For genanvendt PET er tabet
we assumed that the efficiency was the same based on
højere end for ikke genanvendt LDPE (24,5% for
material type (ex/ same for all LDPE types).
genanvendt PET sammenlignet med 9,7% for
Of course the recovery efficiencies could be lower if the
LDPE). Tabet er måske i højere grad afhængigt af
quality of the polymer sent to recycling was lower, but we
hvorvidt der er tale om genanvendt eller virgint plast did not have data to substantiate assumptions on lower
og ikke polymer-afhængigt? Vi mener, at tabet for
recovery rates and higher residues production.
genanvendt LDPE er sat for lavt.
In any case, even with high recovery rates and low amount
of residues produced, EOL2 resulted rarely among the pref-
erable end-of-life options.
These assumptions are now specified in Section 3.
Antagelse af at rest-produkter fra sortering til gen-
Specified in the text.
√
anvendelse af plast- og papirposer foregår i Dan-
Yes, recycling does not occur in Denmark.
mark – det sker ikke i dag. Bør det ikke antages, at The cardboard packaging is assumed to be collcted in
det sker i Tyskland eller Sverige – og dermed ikke
Denmark, but then transported abroad (Europe) for sorting
går til forbrænding i DK? Betyder det ikke det store, and recycling. The same is assumed for the collection for
så argumenter for det.
recycling for all the separately collected fractions, which are
transported abroad (Europe), sorted and recycled.
In both cases, residues are incinerated in an average Euro-
pean incineration process (which was modelled with Ecoin-
vent processes) and are not assumed to be incinerated in
Denmark.
136 The
Danish Environmental Protection Agency / LCA of grocery carrier bags
The location of the recycling plat was not disclosed by the
project partners, so we assumed a general transportation
distance of 2000 km (including also southern Europe) and
used Ecoinvent processes based on Europe when possible.
antagelser vedrørende elektricitetsproduktion
I valgt en fremtidig marginal for elektricitet - Er dette Specified in the text.
√
korrekt når nu FU siger 2017?
Yes, the functional unit is based on carrier bags available
for purchase in Danish supermarkets in 2017. However,
since the study is assumed to support decisions that will
occur in a 10 year period, using a future marginal energy is
assumed to well represent the effects in the future waste
management system.
Moreover, this LCA study is part of a series of assessments
conducted by DTU for the Miljøstyrelsen in the end of 2017
regarding decision support for future waste management
options. All the assessments are based on the same mar-
ginal energy choices.
afskæringskriterier for den indledende/første medta-
gelse af input og output, herunder
beskrivelse af afskæringskriterier og antagelser
√
udvælgelsens indvirkning på resultater
Savner en kommentar på hvad udelukkelse af gen-
Specified in the text (line 1029-1038).
√
anvendelse af tekstilerne og biopolymeren betyder. Excluding recycling for textiles and biopolymers means that Vi kan ikke helt følge
carrier bags of these materials will only be tested for EOL1
argumentationen for ikke
and EOL3. Considering recycling feasible would mean al-
at medtage genanven-
lowing the recovery of these materials through separate
delse af tekstiler, da
collection and re-processing, therefore lowering the impacts indsamlingsmetoden (at
connected to the production of the carrier bags. Recycling of den ikke foregår i kom-
textiles was not taken into account since it mainly occurs
munalt regi) ikke skulle
outside the Danish waste management system, for example påvirke genanvendelsen.
via charity organizations or through return schemes at re-
Vi tænker mere, at ar-
tailer shops. The extent of recovery of materials can be
gumentet skal være, at
extremely variable according to the specific collection se-
der kun i ringe grad på
lected. Regarding biopolymer carrier bags, which are com-
nuværende tidspunkt
The Danish Environmental Protection Agency / LCA of grocery carrier bags
137
postable starch-biopolymer bags, we did not include materi- sker materialegenan-
al recovery through composting, since biopolymer bags are vendelse af tekstiler,
currently sorted out from organic waste management plants. men primært genbrug,
som ikke er så relevant i
denne evaluering.
medtagelse af afskæringskriterier for masse, energi
Ikke specifikt uddybet.
Corrected.
√
og miljø
We have re-written the system boundaries section, provid-
ing a better description of the inputs and outputs.
Livscykluskortlægning
dataindsamlingsprocedurer
√
kvalitativ og kvantitativ beskrivelse af enhedsproces-
Der savnes beskrivelse af f.eks. om processerne
Specified in the text (line 1079).
√
ser
inkluderer biomassebegrænsning.
Biomass was not considered a limited resource.
kilder til udgivet litteratur
Der savnes en kilde på de 30% mindre udbytte fra
Added.
√
økologisk bomuldsproduktion (s. 35, linje 862)
The yield of organic cotton farming was assumed 30 %
lower than conventional cotton. For the modelling, this im-
plies that 30 % more impacts are considered for the produc-
tion of organic cotton than conventional cotton. The yield
was found to vary in the literature between 20 % and 40 %
and according to the geographical location (Forster et al.,
2013). Since the Ecoinvent dataset for cotton production is
not linked to a specific geographical location, 30 % was
considered as average value. The selected value influences
the contribution of the production process to the overall
impacts related to the organic cotton carrier bag.
beregningsprocedurer
√
validering af data, herunder
datakvalitetsvurdering
Mangler, f.eks. vurderes det ikke, hvad det betyder, Added.
√
at nogle processer er globale i stedet for europæi-
In Section 3, we have provided a discussion on data re-
138 The
Danish Environmental Protection Agency / LCA of grocery carrier bags
ske.
quirements, assumptions used to provide missing data, and
critical assumptions.
In Section 5, we have provided a discussion of the results in
the light of data quality and assumptions.
Critical assumptions have been tested as sensitivity analy-
sis and discussed in Section 7.
Among other data issues, we have specifically discussed
the influence on the results of the choice of European ver-
sus global data.
behandling af manglende data
√
følsomhedsanalyse til raffinering af systemgrænsen
1. "Choice of reference flow" – lidt svært at forstå
Specified in the text and in the sensitivity analysis.
√
hvordan antallet af poser er beregnet. Kan det be-
The reference flow for each bag subtype in Table 3 was
skrives bedre, hvordan den nye ydeevne (antal
calculated taking into consideration both volume and weight
genstande) relateres til de anvendte ydeevner i
holding capacity as conditions that had to be fulfilled at the
resten af studiet (bæreevne og volumen).
same time. This means that, for each carrier bag, if the
volume or/and the weight holding capacity were lower than
the ones specified in the functional unit, we assumed that
the customers would need to buy two bags instead of one in
order to comply for the same functionality (a grocery shop-
ping of the volume of 22 litres and/or a weight of 12 kilo-
grams). When a bag was required two times, it was mod-
elled by multiplying by two the average weight and volume
provided in Table 2. In the cases of biopolymer and paper
carrier bags, the weight holding capacity surveyed was in
average compliant with the virgin LDPE carrier bag, but
provided the highest variance between the samples. For
example, the weight that these types of bags were capable
of holding varied greatly in the tested samples, especially if
the items placed in the bags for the survey had sharp an-
gles, which tore the bags much more easily than for other
carrier bag types (Alonso Altonaga, 2017). For these rea-
sons, the weight holding capacity for the reference flow was
The Danish Environmental Protection Agency / LCA of grocery carrier bags
139
considered not respected, and that two bags would be re-
quired to carry the same weight.
We have decided to replace the sensitivity analysis that
used the reference flow of the UK study performed by
Edwards and Fry (2011) with a sensitivity analysis that cal-
culated the “fractions” for the carrier bags that required
rounding to two bags in order to provide for the functional
unit.
In the sensitivity analysis, we provided the formula used to
re-calculate the reference flow.
Table 17: Er værdierne for Biopolymer EOL3 kor-
The sensitivity analysis results presented in the previous
√
rekte? De virker lave ift, hvor meget EOL1 værdier-
version of the report (old Table 17) is not present anymore.
ne stiger.
Anyhow, the results for BP, EOL3 were correctly lower than
EOL1: this non-fossil carbon and lightweight carrier bag
provides larger advantages when used for substituting a
virgin LDPE waste bin bag.
3. “Different way to calculate primary reuse” (linje
Agree.
√
1553 og frem) giver ingen mer-værdi. Det er jo bare We have added a sentence in the section “modelling of
om man regner på antal primær genbrug eller antal primary reuse”.
gange man bruger posen i alt. Skriv 1-2 linjer om
Edwards and Fry (2011) performed a similar assessment,
dette i valg af metode i stedet for.
but calculating the number of reuse times simply performing
a ratio between the carrier bag alternative and the reference
carrier bag. Such calculation differs from the method adopt-
ed for the present study by providing the number of reuse
times, instead of the number of times the bag is used in total
(Eq. 2).
Gentager, at vi anbefaler en følsomhedsanalyse,
Added. Please see point 3.3b above.
√
hvor man f.eks. anvender 25 % mindre udledninger
for produktion af jomfruelig LDPE til at repræsentere
den genanvendte LDPE.
allokeringsprincipper og –procedurer, herunder
140 The
Danish Environmental Protection Agency / LCA of grocery carrier bags
dokumentation og begrundelse for allokeringsproce-
Jeg kan ikke læse om der er anvendt biomassebe-
Added (please see above comment 4.2).
√
durer
grænsning eller ej.
ensartet anvendelse af allokeringsprocedurer
√
Vurdering af miljøpåvirkninger i livscyklus, hvis an-
vendt
LCIA-procedurer, beregninger og resultater af vurde-
√
ringen
begrænsninger af LCIA-resultater, som vedrører livs-
√
cyklusvurderingens formål og afgrænsning
sammenhængen mellem LCIA-resultater og formål og I skriver i linje 677 at "Then, the calculated number
Rephrased (now line 792)
√
afgrænsning
of reuse times based on environmental performance “Then, the calculated number of reuse times based on envi-
was compared to the expected lifetime of the bag
ronmental performance is intended to raise the discussion
and used as a basis for discussion." – Dette synes
among the stakeholders on the effective expected lifetime of
jeg ikke, at jeg kan se af LCIA/diskussionen. Der er each carrier bag.”
ingen kvantitative levetider på poserne.
sammenhæng mellem LCIA-resultaterne og LCI-
√
resultaterne
påvirkningskategorier og kategoriindikatorer under
√
betragtning, herunder den logiske begrundelse for, at
de er valgt, herunder antagelser og begrænsninger
beskrivelse af eller henvisning til alle anvendte karak-
√
teriseringsmodeller, karakteriseringsfaktorer og meto-
der, herunder antagelser og begrænsninger
beskrivelse af eller henvisning til alle anvendte værdi-
-
baserede valg i forhold til påvirkningskategorier, ka-
rakteriseringsmodeller, karakteriseringsfaktorer, nor-
malisering, gruppering, vægtning og, andre steder i
LCIA-en, en begrundelse af deres anvendelse og
påvirkning på resultaterne
en erklæring om, at LCIA-resultaterne er relative ud-
Mangler
Added both in the LCIA methods description and in the
√
The Danish Environmental Protection Agency / LCA of grocery carrier bags
141
tryk, som ikke forudsiger påvirkninger på kategori-
section providing the characterized results.
end-point, eller overskridelser af tærskelværdier, sik-
kerhedsmarginer eller risikoniveauer og, når medtaget
som en del af livscyklusvurderingen (LCA), også
en beskrivelse af og begrundelse for definitionen og
√
beskrivelsen af eventuelle nye påvirkningskategorier,
kategoriindikatorer eller karakteriseringsmodeller
anvendt til LCIA'en
en fremstilling af og begrundelse for eventuel gruppe-
na
ring af påvirkningskategorierne
eventuelle yderligere procedurer, som omregner indi-
na
katorresultaterne, og en begrundelse for de valgte,
referencer, vægtningsfaktorer etc.
en eventuel analyse af indikatorresultaterne, fx føl-
√
somheds- og usikkerhedsanalyse eller anvendelse af
miljødata, herunder eventuel betydning for resultater-
ne
data og indikatorresultater fra før en eventuel normali- √
sering, gruppering eller vægtning skal gøres tilgænge-
lige sammen med de normaliserede, grupperede eller
vægtede resultater
Livscyklusfortolkning
resultaterne
Kan det specificeres yderligere, hvad det f.eks. er i
Added contribution analysis for the production part for each √
materialeproduktion der betyder mest for udlednin-
carrier bag type (Tables 13-21).
gerne?
Kunne man ud fra konklusionerne om, hvor mange
We have decided not to do this, as it will have a part as-
√
gange poserne skal genanvendes for at matche
sumptions on average life times. We will leave this to the
miljøeffekten for referencen, for hver posetype vur-
EPA in their choice on how they wish to use the report. We
dere, hvorvidt dette er realistisk? Evt. med en farve- have commented further on the importance to do such a
skala (grøn=realistisk, gul=måske og rød=ikke reali- realism check.
stisk)? Som støtte til beslutningstagere. Evt. i resu-
142 The
Danish Environmental Protection Agency / LCA of grocery carrier bags
meet.
antagelser og begrænsninger, som vedrører fortolk-
Kan der siges noget om, hvad betyder, det at nogle Added.
√
ningen af resultater, både metodik- og datarelaterede af materialeproduktionerne er globale, andre euro-
We have added a specific paragraph on assumptions and
pæiske og nogle andre dele af verden?
critical assumptions.
In particular, with respect to dataset referring to differen
geographical locations:
“In general, market and global datasets provided slightly
higher emissions than production datasets in specific geo-
graphical locations. Therefore, the carrier bags for which
only production datasets were available are likely to have
slightly lower emissions than using market datasets. Assum-
ing that the carrier bag manufacturers retrieve materials and
energy from the market, our preference was always for the
market datasets. When not available, we used production
datasets, preferably for Europe.”
datakvalitetsvurdering
Mangelfuld
Added a discussion of the results with respect to the high-
√
lighted data limitations and assumptions.
fuld gennemskuelighed, hvad angår værdibaserede
√
valg, logiske begrundelser og ekspertvurderinger
Kritisk review
navn på og tilhørsforhold for de personer, der udfører Navne skal tilføjes
√
review
redegørelse fra kritisk review
√
svar på anbefalinger fra det kritisk review
Kommer senere
√
The Danish Environmental Protection Agency / LCA of grocery carrier bags
143
Life Cycle Assessment of grocery carrier bags
Currently, Danish supermarkets provide multiple-use grocery carrier bags of different
materials (such as plastic, paper and cotton) that are designed for multiple uses. In
order to compensate the environmental impacts connected to the production of the
bags, these multiple-use carrier bags need to be reused a number of times.
This Life Cycle Assessment study examined the environmental impacts connected to
the production, distribution, use and disposal of multiple-use grocery carrier bags
available for purchase in Danish supermarkets for a range of environmental indica-
tors. The study identified which carrier bags provide the lowest impacts for their pro-
duction and which is the optimal disposal option for specific carrier bag materials.
The goal of the study was quantifying the required minimum number of reuse times
for each of the multiple-use carrier bags based on their environmental performance.
The Danish Environmental
Protection Agency
Haraldsgade 53
DK-2100 København Ø
www.mst.dk