Study to assist the Commission to carry out a life cycle impact assessment of different possibilities to reduce the consumption of very lightweight plastic carrier bags : final report.
Date: 2016-07-27
Institutions: Directorate-General for Environment
Subjects: environmental impact, environmental policy, packaging product, plastics, plastics industry, prevention of pollution, waste recycling

Study to assist the Commission 
to carry out a life cycle impact 
assessment of different 
possibilities to reduce the 
consumption of very lightweight 
plastic carrier bags 

Final report 

July – 2016 

 
 
 
 
 
 
 
 
 
 
  
 
 
 
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Luxembourg: Publications Office of the European Union, 2016 

ISBN 978-92-79-60686-1 
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Reproduction is authorised provided the source is acknowledged. 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Study to assist the Commission to carry out 
a life cycle impact assessment of different 
possibilities to reduce the consumption of 
very lightweight plastic carrier bags 

Final Report  

Ann Ballinger 

Simon Hann 

20th July 2016 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Report for Marianne Muller on behalf of The European Commission, DG 
Environment 

Prepared by Simon Hann, Ann Ballinger 

Approved by  

Dominic Hogg 

(Project Director) 

Eunomia Research & Consulting Ltd 
37 Queen Square 
Bristol 
BS1 4QS 

United Kingdom 

Tel: +44 (0)117 9172250 
Fax: +44 (0)8717 142942 

Web: www.eunomia.co.uk 

Disclaimer 

Eunomia Research & Consulting has taken due care in the preparation of this report to 
ensure that all facts and analysis presented are as accurate as possible within the 
scope of the project. However no guarantee is provided in respect of the information 
presented, and Eunomia Research & Consulting is not responsible for decisions or 
actions taken on the basis of the content of this report. 

 
 
 
 
 
 
 
 
 
 
 
 
Executive Summary 

This study uses life cycle assessment (LCA) methodology under the Product 
Environmental Footprint (PEF)1 framework to compare the environmental performance 
of very lightweight plastic carrier bags—defined as those plastic carrier bags under 15 
micrometres in thickness which are required for hygiene purposes or provided as 
primary packaging for loose organic produce.  

The objective of the study is to identify different possibilities to reduce the consumption 
of very lightweight plastic carrier bags, by replacing them with other products that can 
fulfil the same functions.  Performance characteristics have been assessed by 
undertaking a limited environmental footprint impact assessment of these possibilities 
using secondary data in the form of a ‘screening study’.  

The alternatives focused upon in this study are; 

  High density polyethylene (HDPE) bags (current situation); 
  Paper bags; 
  Compostable polymer bags (to EN 13432): 

o  Starch with polycaprolactone (PCL); and 
o  Polylactic acid (PLA). 

For the baseline scenario it was assumed that there would be no second use or reuse for 
HDPE as these bags an either suitable for use as residual refuse liners or recommended 
for use as a liner for organic waste due to being non-compostable. Based on EU paper 
recycling rates, paper bags are assumed to be recycled 72% of the time. The 
compostable polymer bags are assumed to be reused as an organic household waste bin 
liner 30% of the time. 
Within the limitations of the secondary data and the scope of the study the main 
conclusion that can be drawn from analysing the results is that there is no specific 
material that outperforms the others in all environmental footprint categories. As such 
it is not possible to choose one over another. Moreover, the results also demonstrate 
that different types of compostable plastics vary in terms of the environmental 
impacts. To encourage the use of this material in general will not always lead to the best 
environmental outcome. This study focuses on two compostable plastics which perform 
notably differently; it may be the case that environmental performance of the myriad 
brands on the market may also be significantly variable. The different bio-based 
feedstocks and the differences in the proportion of petrochemical content will have a 
significant effect on this performance. As such, these results confirm that conclusions 

1 Guidance for the undertaking of a PEF study comes from Annex II of Commission Recommendation 
2013/179/EU  http://eur-lex.europa.eu/legal-content/EN/TXT/PDF/?uri=OJ:L:2013:124:FULL&from=EN  

Life Cycle Impact Assessment of Very Lightweight Plastic Bags  

i 

 
                                                      
 
can only be drawn on the performance of individual products rather than the 
compostable plastics product group as a whole. 
The two key parameters that have the most impact are the mass of the plastic bags and 
the proportion that is given a second use as a compostable organic waste liner. The mass 
of plastic used in both the PLA and PCL bags is around 50% more than an HDPE bag 
which is due to the increased material density (a fairly static parameter) and the 
thickness of the film. This thickness may be decreased to improve the relative 
environmental performance, but potentially at the expense of product performance. The 
second use as a compostable organic waste liner, in particular, requires a sufficient 
thickness to carry the weight of the waste and to not degrade whilst in use so that the 
bag begins to split apart or fragments. 
Where levels of second use as organic household waste bin liner are relatively—and 
perhaps unrealistically— high (~80%), the compostable bags have the potential to 
outperform HDPE in respect of climate change impacts but rarely in other environmental 
footprint categories. There also may be specific practical issues with taking such an 
approach for individual member states as organic household waste collection systems 
and their respective treatment processes can vary. 
Figure E - 1 shows the comparative results showing the environmental footprint 
categories that are deemed to be the most methodologically robust.  

Figure E - 1  Comparative Life cycle Results – Robust Categories Only 

ii 

 
 
 
 
 
Potential littering impacts are also considered separately due to the lack of a recognised 
methodology that can fully consider these impacts in the context of an LCA study. 
Research suggests that whilst littering is of great importance when considering the 
environmental profile of the larger, thicker, carrier bags, it is potentially less important 
for very lightweight plastic carrier bags due to the way in which they are used. Impacts 
are likely to be worse for all forms of plastic bag; the output from analysing 
biodegradation studies suggest that littering compostable plastic bags is likely to result in 
a similar environmental impact to HDPE bags. These bags are primarily designed for 
composting and therefore need a strict set off conditions (heat, moisture, bacteria) to 
degrade fully. Such conditions are unlikely to be present in the environment to which the 
bags are littered. This may lead the bags to persist in the environment thereby becoming 
a hazard to marine life if they are washed into seas and rivers. 

Life Cycle Impact Assessment of Very Lightweight Plastic Bags  

iii 

 
 
 
Contents 

Executive Summary ..................................................................................................... i 

1.0 

2.0 

3.0 

4.0 

5.0 

6.0 

7.0 

Glossary ......................................................................................................... 6 

Background .................................................................................................... 7 

Introduction ................................................................................................... 8 

Review of Literature ...................................................................................... 11 

Product Environmental Footprint (PEF) .......................................................... 15 

Goal Definition .............................................................................................. 15 

Scope Definition ............................................................................................ 17 

7.1  Unit of Analysis and Reference Flow .................................................................... 17 

7.2 

System Boundaries ................................................................................................ 19 

7.2.1  Allocation ........................................................................................................ 21 

7.2.2 

Biogenic Carbon.............................................................................................. 21 

7.3 

Environmental Footprint Impact Categories and Assessment Methods .............. 22 

7.4  Assumptions .......................................................................................................... 23 

7.4.1 

Transport ........................................................................................................ 23 

7.4.2 

End of life ........................................................................................................ 24 

8.0 

Resource and Emission Profile ....................................................................... 27 

8.1  Data Sources ......................................................................................................... 27 

9.0 

Environmental Footprint Impact Assessment - Results ................................... 29 

9.1 

Interpreting the Results from the Study ............................................................... 29 

9.2  Comparison of Product Performance – Central Case ........................................... 32 

9.3 

Sensitivity Analysis ................................................................................................ 36 

9.3.1 

Second use as organic household waste bin liner and Recycling Scenarios ... 36 

9.3.2  Organic household Waste Bin Liner Size ........................................................ 40 

9.4  Results Interpretation and Discussion .................................................................. 41 

9.4.1 

Comparison with other studies....................................................................... 41 

9.4.2  Use of Secondary Data ................................................................................... 42 

9.4.3  Differences in Anaerobic Digestion across Europe ......................................... 43 

10.0 

Littering ........................................................................................................ 44 

4 

 
 
10.1 

Environmental Biodegradation ......................................................................... 44 

10.2 

Effects on Fauna ................................................................................................ 46 

10.3 

Littering Impact factor ....................................................................................... 47 

11.0 

Conclusions ................................................................................................... 49 

APPENDICES .............................................................................................................. 51 

A.1.0 

Literature Review .............................................................................................. 52 

A.2.0  General Assumptions and Calculations ............................................................. 68 

A.3.0  Results Breakdown by Material and Life Cycle Stage ........................................ 73 

 
 
 
 
1.0  Glossary 

Bio-based 

Material intentionally made from substances derived from organic matter. 

EF Category 

Environmental Footprint Category—A way of categorising environmental impacts of 
materials and processes by the effects they are expected to have. 

GWP 

Global Warming Potential 

HDPE 

High density polyethylene 

LCA 

Life Cycle Assessment 

LDPE 

Low density polyethylene 

PEF 

Product Environmental Footprint 

PLA 

Polylactic Acid— a polyester derived from renewable resources. 

Screening Study 

A study based predominantly on secondary data that is used to identify the key 
environmental life cycle impacts and is often used to decide where to focus design 
changes or primary research for a full LCA study. Also referred to a limited study under 
the terms of reference for this project.  

6 

 
 
 
 
 
2.0  Background 

In April 2015 Directive 2015/7202 was adopted by the European Parliament with regard 
to reducing the consumption of lightweight plastic carrier bags—defined as “plastic 
carrier bags with a wall thickness below 50 microns". It was brought in as an amendment 
to Directive 94/62/EC3 which was originally adopted to prevent or reduce the impact of 
packaging and packaging waste on the environment, but did not directly address the 
issues of lightweight plastic carrier bags. The measures specified by the new Directive 
require either of both of the following to be undertaken by Member States; 

  Annual consumption of lightweight plastic carrier bags does not exceed 90 

bags per person by 2020 and 40 bags by 2026; and 

  By 2019 lightweight plastic carrier bags are not provided free of charge. 

Very lightweight plastic carrier bags plastic carrier bags are defined in Directive 94/62/EC 
as: 

“very lightweight plastic carrier bags” shall mean plastic carrier bags with a wall 
thickness below 15 microns which are required for hygiene purposes or provided 
as primary packaging for loose organic household when this helps to prevent 
organic household wastage” 

Very lightweight plastic carrier bags are currently excluded from the measures aiming at 
reduction of plastic carrier bag consumption after proposed Amendments4 13 and 33 
were not withheld during the legislative process; 

  Amendment 13 asserted that biodegradable and compostable materials are 
less harmful to the environment than conventional plastic carrier bags and 
that very lightweight carrier bags should be replaced by these materials or 
recycled paper; and, 

  Amendment 33 looked to set targets for the substitution of very lightweight 

plastic carrier bags for these alternatives. 

Due to the absence of scientific and objective information on the relevant life cycle 
impacts of these alternatives, it was first required that the Commission gather the 
relevant information in this respect. The information would be used to decide whether 
or not legislation should be introduced obliging Member States to ensure that very 
lightweight plastic carrier bags should be replaced by alternatives that perform better 
from an environmental point of view. 

2 http://eur-lex.europa.eu/legal-content/EN/TXT/PDF/?uri=CELEX:32015L0720&from=EN  
3 http://eur-lex.europa.eu/legal-content/EN/TXT/?uri=celex:31994L0062  
4 http://www.europarl.europa.eu/sides/getDoc.do?pubRef=-//EP//NONSGML+REPORT+A7-2014-
0174+0+DOC+PDF+V0//EN  

 
                                                      
 
Therefore article (20a 3) was subsequently adopted which states that:  

"by 27 May 2017, the Commission shall assess the life cycle impacts of different 
possibilities to reduce the consumption of very lightweight plastic carrier bags, 
and present a legislative proposal, if appropriate. "  

To this effect, this study uses the life cycle assessment methodology to compare the 
environmental performance of very lightweight plastic carrier bags. The objective of the 
study is therefore to identify different possibilities to reduce the consumption of very 
lightweight plastic carrier bags, by replacing them with other products that can fulfil the 
same functions.  Performance characteristics have been assessed by undertaking a 
limited environmental footprint impact assessment of these possibilities.  

This analysis and the conclusions thereof shall support the Commission in assessing 
whether it would be appropriate to propose legislation obliging Member States to 
ensure that the currently used very lightweight plastic carrier bags are (gradually and / 
or partially) replaced by the alternatives identified, where these alternatives have a 
more positive environmental footprint. 

The study is carried out under Commission Recommendation 2013/179/EU5 on the use 
of common methods to measure and communicate the life cycle environmental 
performance of products and organisations. 

3.0 

Introduction 

Very lightweight plastic carrier bags are primarily used for containing loose goods such 
as fruit and vegetables or for hygiene purposes to prevent contamination from meat 
products. Their use in itself may help waste prevention, as consumers can pick the 
quantity of the product they need and can also account for a reduction in packaging. On 
the other hand, these bags in themselves easily generate plastic packaging waste as they 
are used only once, are not recycled and end up in the residual household waste. The 
current material often in use—an un-biodegradable high density polyethylene (HDPE)—
may not be the best material from an environmental point of view and therefore 
alternative materials must be assessed to discover whether there is an environmental 
justification for the move to alternatives. 

The objective of this study is, therefore to identify which products are viable alternatives 
to very lightweight plastic carrier bags and whether these alternatives may have a lower 
impact on the environment. This would make these bags preferable to the currently 
used very lightweight plastic carrier bags. 

The study provides a limited environmental assessment of alternatives to the very 
lightweight plastic carrier bags. There are not many alternatives to very lightweight 

5 http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2013:124:0001:0210:en:PDF  

8 

 
 
                                                      
 
plastic carrier bags and the list is therefore limited. Based on the materials that are most 
commonly used for the same purpose in Europe, the alternatives are6,7: 

  Paper bags (with and without recycled content); 
  Polymer bags which are biodegradable in industrial composting (compliant 

with standard EN 13432). 

At the outset it is also important to discuss and make clear the terminology that will be 
used throughout the report especially with regard to biodegradability. The term 
biodegradable is essentially meaningless when used in isolation: its use needs to be 
qualified by placing it in the context of where the biodegradation is deemed to occur. 
This can be in the soil, in commercial or home composting, anaerobic digestion, in the 
rivers and oceans, or in the open environment (i.e. littered). Each environment has its 
own temperature, UV level, moisture level and bacterial and fungal colonies which 
govern the likelihood and speed of biodegradation of different materials.  

Biodegradable and compostable are also often used interchangeably. It is true to say 
that a compostable plastic is biodegradable, but a biodegradable plastic is not always 
compostable. Since composting—whether via a commercially operated system or taking 
place at home—is just one environment within which a material may biodegrade, it is 
important that a clear distinction be made between the two terms. 

It is also important to consider the popular misconception that the raw material used for 
a plastic is directly related to its biodegradability. Some plastics are made almost entirely 
from bio-based and potentially renewable resources; plastics made from such sources 
can be designed to biodegrade8 (under certain conditions), but equally, can also be 
designed such that it behaves as a conventional plastic.9 Similarly, there are also fossil 
based plastics available which are designed to biodegrade.10 Therefore, not all bio-based 
plastics are biodegradable and not all biodegradable plastics are bio-based; 
biodegradability is function that is independent of the raw materials used in the 
manufacturing process.  

There are many brands and formulations on the EU market for compostable polymer 
bags (compliant with standard EN 13432) and therefore a small sample is chosen to 
represent two of the different types available;  

6 It should be noted that the alternatives may not necessarily be below 15 microns in order to fulfil the 
function of the product 
7 Oxo-degradable plastic carrier bags are excluded from the scope of this study as the assessment of the 
impact of oxo-degradable plastic carrier bags is being considered as part of on-going work by the 
Commission pursuant to Article 20a (2) of Directive 94/62/EC as amended by Directive (EU) 94/62/EC.  
8 NatureWorks (2016) Turning Greenhouse Gases into Ingeo Biopolymer, accessed 6 January 2016, 
http://www.natureworksllc.com/The-Ingeo-Journey/Raw-Materials 
9 Braskem (2016) I’m GreenTM Polyethylene, accessed 1 June 2016, http://www.braskem.com/site.aspx/Im-
greenTM-Polyethylene 
10 BASF (2016) Biodegradable and Compostable Packaging solutions with ecoflex®, accessed 1 June 2016, 
http://product-finder.basf.com/group/corporate/product-finder/en/brand/ECOFLEX 

 
                                                      
 
  Maize starch with polycaprolactone; and 
  Polylactic Acid (PLA). 

The first of these two materials is a mixture of bio-based starch and petroleum based 
polymer (polycaprolactone). The second is a purely bio-based plastic usually made from 
corn starch. The two types of bags are thus made from very different feedstocks. Both 
types are used extensively within the EU and conform to EN 13432. 

An environmental assessment has been conducted using the life cycle assessment 
approach in line with the Product Environmental Footprint (PEF) methodology – from 
Annex II of Commission Recommendation 2013/179/EU11 on the use of common 
methods to measure and communicate the life cycle environmental performance of 
products and organisations  - which has been followed as far as possible. 

As the objective of this study is to carry out a limited assessment, the analysis has been 
streamlined using secondary data to provide an indicator to the Commission of the likely 
outcome of the environmental section of undertaking a full impact assessment. 
Importantly, the conclusions are also only valid for the materials used in the study—the 
compostable polymers chose, for example, are only representative of those particular 
materials and not all bio/compostable polymers.  

The report starts with a summary of other literature on this topic, which is presented in 
Section 4.0 (a more detailed review of the literature is presented in A.1.0). The 
methodology is set out in Section 5.0 through to Section 7.0 – starting with a description 
of the requirements of the PEF methodology. The results of the analysis are presented 
and discussed in Section 9.0. 

In addition to consideration of the impacts under the PEF methodology, the study also 
considers the impact of littering the different types of bags. These impacts cannot be 
readily assessed using life cycle assessment, and are therefore considered separately in 
Section 10.0. The report concludes in Section 10.3, which includes a summary of key 
messages arising from the analysis. 

11 http://eur-lex.europa.eu/legal-content/EN/TXT/PDF/?uri=OJ:L:2013:124:FULL&from=EN  

10 

 
 
 
 
                                                      
 
4.0  Review of Literature 

During the course of the literature review no studies were found that were focused 
specifically on comparisons between different types of very lightweight plastic carrier 
bag material. Indeed, all studies identified as potentially relevant have concentrated on 
lightweight carrier bags made of different materials and in particular whether reusable 
bags are preferable to single use variants. However, elements of these studies provide a 
useful background and a foundation for the building of a model specifically for very 
lightweight plastic carrier bags.  

A more detailed review of a number of key studies is provided in Appendix A.1.0. Table 1 
provides an overview of the results of the LCA studies that have been analysed as part of 
this report. The table includes a rating for the relative performance of each option with a 
rating of 1, indicating the best environmental performance. Only results relating to the 
types of bags considered in this study are shown. The table also confirms who the report 
was commissioned by and whether it was peer reviewed. This is important as 
government funded studies with a peer review can generally be considered to be more 
reliable. Results from industry funded studies without a peer review should be viewed 
with greater caution. However, valuable insights can be potentially gained from both. 

All of the studies included GHG emissions as an environmental indicator. Some included 
other indicators such as littering. However, as no standard methodology exists for 
littering impacts, the calculation methodologies for littering impacts varied widely and in 
most cases failed to truly capture the effects of littering in a fair and balanced way. 

Given the large number of assumptions involved where LCA studies are undertaken, it is 
frequently difficult to understand the detail of the approach taken by authors when 
modelling the performance of different options. As such, it is useful to separately 
consider those studies where a peer review has been undertaken, where assumptions 
will have been reviewed in greater detail by others independent from the authors of the 
original study. The peer review process provides a level of credibility to the study and it 
is accepted practice that this is performed for public facing studies. 

All four of the peer reviewed studies conclude that HDPE bags perform the best from an 
environmental perspective, although only two of these included any form of litter 
assessment. All studies that do include litter metrics hinge upon the assumptions around 
how quickly the material biodegrades in the open environment. There appears to be 
contradicting evidence for this making it difficult to reach a clear consensus with regards 
to the relative impacts.  

One study that suggests that compostable plastic is the most favourable is the 
Environment Australia (2002) study; however, the following year the result is 
contradicted in the Dept. of the Environment and Heritage (2003) study which involved 
the same authors.  

 
 
Table 1 – Comparison of Environmental Impacts from LCA Studies 

Study 

Intertek (2011)1 

Intertek (2012)2 

Imperial College 
(2008) 3 

R
e
g
i
o
n

UK 

UK 

UK 

R
e
p
o
r
t

F
o
r

Government 

Industry 

Industry 

Boustead (2007) 4 

USA 

Industry 

Clemson University 
(2014) 5 
Eco-Bilan (2004) 6 

USA 

University 

France 

Industry 

Australia  Government 

Environment 
Australia (2002) 7 
Dept. of the 
Environment and 
Heritage (2003)8 

P
e
e
r
R
e
v
i
e
w

Yes 

No 

Yes 

Yes 

Yes 

Yes 

No 

I

n
c
l
.

L
i
t
t
e
r

No 

Yes 

No 

No 

Yes 

Yes 

Yes 

Ranked performance of options in 
study (1 = best, 3 = worst) 

HDPE 

Compostable 
Plastic 

Paper 

1 
1 

2 

1 

1 

1 

2 

1 

2 
2 

1 

3 

n/a 

2 

1 

2 

3 
n/a 

n/a 

2 

2 

3 

3 

3 

Australia  Government 

No 

Yes 

1. 

2. 

Intertek Expert Services (2011) Life Cycle Assessment of Supermarket Carrier Bags: A Review of the Bags 
Available in 2006, Report for Environment Agency, February 2011: 
www.gov.uk/government/uploads/system/uploads/attachment_data/file/291023/scho0711buan-e-e.pdf  

Intertek Expert Services (2012) A Life Cycle Assessment of Oxo-biodegradable, Compostable and Conventional 
Bags, Report for Symphony Environmental Ltd, May 2012, 
www.biodeg.org/New%20LCA%20by%20Intertek%20%20-
%20Final%20Report%2015.5.12%281%29%20%281%29.pdf  

3.  Murph, D.R.J., Davis, D.G., and Payne, M. (2008) Life Cycle Assessment (LCA) of Biopolymers for single-use 
Carrier Bags, Report for NNFCC, September 2008 www.nnfcc.co.uk/tools/lca-of-biopolymers-for-single-use-
carrier-bags-nnfcc-07-005  

4.  Boustead Consulting (2007) Life Cycle Assessment for Three Types of Grocery Bags - Recyclable Plastic; 

Compostable, Biodegradable Plastic; and Recycled, Recyclable Paper, Report for Progressive Bag Alliance, 2007 
www.heartland.org/sites/default/files/threetypeofgrocerybags.pdf  

5.  Kimmel, R.M., Cooksey, K.D., and Littman, A. (2014) Life Cycle Assessment of Grocery Bags in Common 

Use in the United States, Report for Clemson University, 2014 
https://cup.sites.clemson.edu/pubs/grocery-bags/grocery-bags.pdf  

6.  Ecobilan (2004) Évaluation des Impacts Environnementaux des Sacs de Caisse Carrefour, Report for 

Carrefour, 2004 
www.ademe.fr/sites/default/files/assets/documents/28300_acv_sacs_carrefour_2004.pdf 

7.  RMIT Centre for Design, and Eunomia Research and Consulting Ltd (2002) Plastic Shopping Bags – 

Analysis of Levies and Environmental Impacts, Report for Environment Australia, 2002 
www.environment.gov.au/archive/settlements/publications/waste/plastic-bags/pubs/analysis.pdf  

8.  ExcelPlas Australia, Centre for Design at RMIT, and Nolan-ITU (2003) The Impacts of Degradable 

Plastic Bags in Australia, Report for Department of the Environment and Heritage (Australia), 2003 
http://pandora.nla.gov.au/pan/51767/20050826-
0000/www.deh.gov.au/settlements/publications/waste/degradables/impact/pubs/degradables.pd
f  

12 

 
 
 
 
 
 
 
 
 
The Imperial College (2008) study also finds that—under some circumstances—one 
compostable plastic bags type can perform better than HDPE, but it is assumed that this 
bag used around 25% less material than HDPE. This goes against many of the other 
studies which suggest that a higher proportion of bio-based plastic is required to 
perform the same function. Importantly, although the study was government funded it 
was performed for a UK organisation linked to bioplastics. 

All studies but one consider that paper is generally the worst performing material. Only 
Boustead (2007) found that paper performed better than bio-based material. Although 
this is partly due to their assumption that paper bags can carry 50% more groceries, the 
GHG emissions from the production process appears to be significantly lower than other 
studies. It is unclear why this is the case. 

As indicated before, none of the studies looked at very lightweight plastic carrier bags 
specifically, and therefore many of the assumptions and conclusions are not directly 
applicable to this study as it focusses on the very lightweight plastic carrier bags. 
However, they can provide a basis for comparison of the results of this study and the 
beginnings of a methodology that can attempt to quantify littering impacts. With this in 
mind, a few key themes were found to be consistent across these studies which often 
have a large bearing on the results: 

  The gauge (thickness) or the material; 
  The relative ability for different materials to make stronger or weaker bags 

(this is directly related to point one); 
  The speed in which materials biodegrade; 
  The end of life scenarios—how much is assumed to be littered and/or to end 

up in landfill; and 

  The assumptions used with regard to second use as bin liner and the resulting 

avoided products. 

The assumptions used in this study that relate to these areas will need to be 
substantiated with strong evidence or, if unavailable, a sensitivity analysis that will allow 
realistic scenarios to be developed. 

Our review also identified several areas that do not appear to have been covered to a 
great extent within the literature considered. Some authors have highlighted that there 
may be a need to consider potential impacts resulting from land use change, which may 
result from farmers ploughing up forest or grassland so that the land may be used for 
growing the crops that are used to make the bio-plastic.12 This impact can be avoided by 
ensuring that the bio-plastic precursors are grown on carbon poor land, or are derived 
from waste based feedstocks. The issue does not appear to have been considered in the 

12   Piemonte, V., and Gironi, F. (2011) Land-Use Change Emissions: How Green are the Bioplastics?, 
Environmental Progress & Sustainable Energy, Vol.30, No.4, pp.685–691; Gironi, F., and Piemonte, V. 
(2010) Bioplastics Disposal: How to Manage it, Transactions on Ecology and the Environment, Vol.140, 
pp.261–270 

 
                                                      
 
studies reviewed in the sections above. Consideration of these impacts may worsen the 
performance of the bio-plastics. Land-use impacts will be considered as part of this 
study, although standard methodologies use generalised assumptions in this area, as it is 
not always easy to discover the exact land use circumstances. As this study will also rely 
on secondary data, issues around land-use cannot be fully resolved.   

There is relatively little detail on the modelling of the end of life scenarios, including 
recycling, incineration, landfill and littering, although this has noted by some authors as 
being an area of particular difficulty. Key considerations in this respect include the 
following: 

  Many of the studies assume that the likely disposal option is landfill, which 
tends to favour the conventional plastic bags. Where landfill impacts are 
considered for paper in particular, a significant proportion of carbon does not 
appreciably degrade, and a number of authors have suggested this should 
result in a credit being applied in respect of the effective sequestration of this 
material.13 Taking such an approach would improve the relative performance 
of the paper and bio-plastic bags. 

  Equally, in the future incineration is increasingly likely to be the default 
disposal option for many European countries. In accounting for these 
impacts, a credit is given for energy generated by the incinerator. The size of 
these credits, however, is expected to decrease over time, particularly where 
electricity generation is concerned, as Member States decarbonise their 
electricity supplies. These impacts would be expected to worsen the relative 
performance of the conventional plastic bags. 

The above impacts will also need to be considered – to the extent that the available data 
allows – when modelling the performance of the different bags.

13  Christensen, T., Gentil, E., Boldrin, A., Larsen, A., Weidema, B., and Hauschild, M. (2009) C Balance, 
Carbon Dioxide and Global Warming Potentials in LCA-modelling of Waste Management Systems, Waste 
Management & Research, Vol.27, No.8, p.707 

14 

 
 
                                                      
 
5.0  Product Environmental Footprint (PEF) 

The Product Environmental Footprint (PEF) is a multi-criteria measure of the 
environmental performance of a good or service throughout its life cycle. Guidance for 
the undertaking of a PEF study comes from Annex II of Commission Recommendation 
2013/179/EU14 on the use of common methods to measure and communicate the life 
cycle environmental performance of products and organisations. 

Its aim is to develop and harmonise a European methodology for environmental 
footprinting using a life cycle approach. Emissions to air, soil and water - along with the 
use and depletion of resources - are measured and categorised.  

PEF guidance specifies five phases for studies undertaken in accordance with the 
methodology - 

  Goal Definition – Setting the aims and requirements; 
  Scope Definition – Providing a framework for the study to be conducted; 
  Resource and Emission profile – compiling an inventory of emissions and 

resource use for each product life cycle;  

  Environmental Footprint Impact Assessment – converting the Resource and 

Emission profile to Environmental Footprint (EF) categories; 
Interpretation – Discussion of what the results mean. 

 

Output from these phases is presented in the sections that follow. 

6.0  Goal Definition 

As identified in the Introduction, this study aims to provide a limited assessment which 
will inform the Commission and help it to decide whether to pursue and investigate 
other alternatives to very lightweight plastic carrier bags. The study has been conducted 
under the Product Environmental Footprint (PEF) framework methodology which has 
been followed as far as possible.  

The work undertaken in this analysis is intended as a ‘screening study'. The objective of 
the study is therefore to identify different possibilities to reduce the consumption of 
very lightweight plastic carrier bags by replacing them by other products that may be 
used for the same purpose, and to undertake a limited environmental footprint impact 
assessment of these possibilities.  

The key elements of the study goal are set out in Table 2 (following the PEF guidance). 

14 http://eur-lex.europa.eu/legal-content/EN/TXT/PDF/?uri=OJ:L:2013:124:FULL&from=EN  

 
                                                      
 
Table 2 – Summary of Study Goal 

Aspects 

Details 

Intended application(s):  

Reasons for carrying out the study 

and decision context: 

Comparisons intended to be 

disclosed to the public: 

Target audience:  

Review:  

This analysis and the conclusions thereof shall 
support the Commission in assessing whether 
it would be appropriate to propose legislation 
obliging Member States to ensure that the 
currently used very lightweight plastic carrier 
bags are (gradually and / or partially) replaced 
by the alternatives identified, where these 
alternatives have a more positive 
environmental footprint 

Article 20a (3) of Directive 94/62/EC as 
amended by Directive (EU) 94/62/EC- 

"by 27 May 2017, the Commission 
shall assess the life cycle impacts of 
different possibilities to reduce the 
consumption of very lightweight 
plastic carrier bags, and present a 
legislative proposal, if appropriate. " 

The study will be made publically available. 

The public at large; decision makers and 
public institutions at EU and Member State 
level 

No third party peer review is planned as this 
is a streamlined assessment. 

Commissioner of the study: 

European Commission 

16 

 
 
 
7.0  Scope Definition 

7.1 

Unit of Analysis and Reference Flow 

The scope of the analysis is very important in determining the parameters of life cycle 
assessment study. Central to the scope are definitions of the unit of analysis and 
reference flow, as these determine the basis upon which the comparisons between 
different products are made. The unit of analysis defines what the product is, how much 
of it there is, and in some cases an indication of product quality and/or product lifespan 
is also used. The reference flow is the amount of product needed in order to provide its 
function. 

There appears to be no specific standard for very lightweight plastic carrier bags; as a 
result, the both the size and gauge of material can vary. There are also many different 
measurement systems that are used by manufacturers. Many manufacturers—
particularly in the US and UK— use inches as the measurement of length and width. 
There are also varying units of measurement for the gauge of plastic material (a 
conversion chart can be found in the Appendix) whilst paper is generally measured by its 
weight in grams per square metre (gsm).  

As most previous studies have found that the strength of the bag material is not the 
limiting factor with regards to how much can be carried within the bag, this study aims 
to compare the bag materials by using the same size bag for all types of material. This 
will enable the bags to be compared based on their carrying capacity. For some bags this 
may involve the use of a bag size that is not, in practice, available on the market at 
present; it being beyond the scope of this study to obtain primary data for the carrying 
capacity of very lightweight plastic carrier bags that are used in the market at present. 
The approach will, however, ensure that the comparison is being made in respect of the 
bag’s function.  

The unit of analysis is therefore defined as the following: 

A bag with dimensions of 228 x 432 mm (9 x 17 inches) 

 
 
 
 
 
 
 
 
 
The materials that will be assessed as part of this study will be the following: 

  High density polyethylene (HDPE) bags (current situation); 
  Paper bags; 
  Compostable polymer bags (to EN 13432): 

o  Starch with polycaprolactone (PCL) (Branded Mater-Bi15); and 
o  Polylactic acid (PLA). 

The purpose of a very lightweight plastic carrier bag differs subtly, but importantly from 
lightweight carrier bags. Very lightweight plastic carrier bags are used in grocery shops to 
either prevent cross contamination from meats, fish and cheese or are used to package 
loose goods such as fruit and vegetables (therefore they are often known as produce 
bags). The latter use also demonstrates one of the key issues around material choice, as 
the loose produce is often weighed and therefore the weight of the bag is also affects 
the price paid. By introducing material that is denser – such as where the construction 
from a particular material requires a thicker gauge or larger surface area - the customer 
is effectively paying a premium for this change. For this reason, the heavier materials 
such as cotton or the thick gauge plastic used in reusable bags—the so-called ‘bag for 
life’—are not appropriate for use in very lightweight plastic carrier bags and are 
therefore out of scope for this study. 

Examples of the bag material identified are shown in Figure 1.  

Figure 1 – Examples of Produce Bags (Compostable, HDPE, Paper) 

Source: www.biobagworld.com , www.interplas.com, www.maddisonsuk.com  

As the gauge of both plastic and paper bags varies, a sensitivity analysis will be also used 
to discover whether the material thickness has a bearing on the results. Table 3 shows 
the upper and lower thickness for each material based on examples of product that are 
currently sold on the European market. For the baseline scenario an average of the 

15 As all bioplastics are proprietary formulas there are no generic polymers.  Starch with polycaprolactone 
is the description of Mater-BI provided by Novamont (www.novamont.com/eng/mater-bi). The material 
has been chosen due to its prevalence within Europe. 

18 

 
 
 
 
                                                      
 
upper and lower thicknesses is used. This average thickness along with the unit of 
analysis (bag size) is used to calculate the mass of each bag—this is the reference flow 
which all other input and outputs are related to. For example, all emissions in the HDPE 
manufacturing processes are defined relative to the mass of product produced (1.95g) 

The calculations for defining the reference flows for each bag are shown in Appendix 
A.2.0. 

Table 3 – Bag Thicknesses and Reference Flow 

Material 

HDPE 

Kraft Paper 

PLA 

PCL 

Sources: 

Thickness 

Average Mass (g) – 
Reference Flow 

81 — 12.52 microns 

373 – 504 gsm 

105 – 156 microns 

10 – 157 microns 

1.95 

8.56 

3.07 

3.10 

1.  www.europackagingonline.co.uk/ecommerce/Bag_on_Roll.html 
2.  www.packagingexpress.co.uk/kraft-paper-flat-fruit-bags  
3.  www.interplas.com/produce-bags 
4.  Personal communication with Smith Anderson Group Ltd  
5.  Personal communication with Novamont 
6.  www.binlinersdirect.com/7-litre-biodegradable-compostable-liners 
7.  biobagusa.com/products/commercial/shopping-produce-bags/   

7.2 

System Boundaries 

The study will be a ‘cradle-to-grave’ assessment with a system boundary that includes 
the following lifecycle stages: 

  Raw materials; 
  Production; and 
  End of Life. 

One further stage usually considered in a life cycle assessment is the use stage which 
would, in this case, consist of the transport of the bag from the supermarket to the 
household by the consumer. No other resources are consumed during the use and it is 
out of scope to consider whether the performance of the bag has any bearing on its 
contents: i.e. whether air permeability affects the longevity of the fruit or vegetables in 
the bag. In this simplified study, transport has been excluded due to the low expected 
impact of the stage on the results. Each product will travel the same distance; the only 

 
 
 
variable is their weight difference which is marginal. Transport impacts are therefore 
expected to be similar for all products. 

One further scenario for the use of compostable plastic bags is also considered, whereby 
these bags are assumed to have a second use as a liner for an organic household waste 
bin. For the second use, the impact of the product it is replacing is subtracted from the 
overall system impacts as it is deemed to be an ‘avoided product’. The environmental 
impacts are therefore defined by the assumption of the proportion of these bags that 
are expected to be used in this way. As there is limited information on what this 
proportion may be, a range has been used to create a sensitivity analysis for this 
variable. This shows the lowest level of second use that is necessary to provide an 
environmentally viable alternative to the HDPE bag. 

There are five possible routes for the end of life: 

  Recycling; 
  Landfill; 
 
  Composting — as anaerobic digestion followed by composting; 
  Litter. 

Incineration with energy recovery; 

The proportion of waste sent to landfill and incineration has been modelled based on 
the European average after a proportion of recycling has been considered. 

For compostable plastic bags, an additional scenario is modelled in which the bag is sent 
to an anaerobic digestion installation after its second use as an organic household waste 
bin liner. It is expected that compostable plastic bags that are not used to collected 
organic household waste will become part of the residual waste stream. 

The PEF guidelines list littering as an example of end-of-life processes that shall be 
should be considered in the PEF study. These guidelines don't provide any further 
guidance except that; 

"As there is often no information on exactly what will happen at the EOL of a 
product, EOL scenarios are to be defined." 16 

Currently there is no established way of assessing the environmental impacts of littering. 
Such impacts are therefore beyond the limits of an LCA to quantify. Drawing upon the 
methods used in the literature reviewed as part of this project in Section 4.0, a 
methodology has been developed to attempt to quantify these impacts both from a 
terrestrial and a marine perspective. The outputs from this element of the study are 
presented in Section 10.0. 

16 EOL: End of life  

20 

 
 
                                                      
 
7.2.1 

Allocation 

The systems investigated during LCAs often produce other products or services as well as 
the product associated with the unit of analysis. Two examples of this are as follows; 

  A waste is sold to be used as a feedstock for another product/process —for 

example, animal manure used as a fertiliser; 

  There are multiple products (co-products) as a result of a process—for 

example, oil refining produces multiple chemicals; 

In these cases a proportion of the environmental impact need to be allocated to either 
the waste part of the system or to the co-product respectively, otherwise the product 
that is the focus of the study is unfairly receiving all of the environmental burden, whilst 
the product that uses the waste as a feedstock is accountable for none of the 
environmental burden. 

This requires consideration of where the environmental impacts (or benefits) of these 
products should be assigned. Resolution of these issues is a often a challenge during LCA 
studies. In line with PEF guidelines and ISO 14044 (ISO, 2006) system expansion is used 
as the preferred approach to address this question. The use of this approach negates the 
need for allocation in the way outlined above. Where system expansion is used, the 
system boundary is expanded, and the other elements are included within the analysis 
through the application of ‘credits’ associated with the reduced need to produce the raw 
materials that have been substituted by the waste product. 

System expansion is used in the following processes during this study; 

  The avoided production of energy as a result of the energy produced during 

the incineration, landfill and anaerobic digestion processes; 
  The avoided production of raw materials when paper is recycled;  
  The avoided production of compostable organic household waste bin liners as 
a results of the second use of compostable plastic carrier bags as bin liner; 
and 

  The avoided production of fertiliser where compostable plastic bags undergo 
a composting process following treatment at an anaerobic digestion facility. 

7.2.2 

Biogenic Carbon 

PEF methodology and ILCD17 guidelines now expect that biogenic carbon – the carbon 
contained within materials such as paper or corn starch - is included as part of the 
environmental footprint calculations. Most existing LCA studies that focus on carrier bag 
comparisons were carried out before the Commission adopted Recommendation 
2013/179/EU (on the use of PEF), are based on the ILCD guidelines and assume that 
biogenic carbon is zero rated. Under such an approach, impacts relating to both the 
uptake of CO2 from the atmosphere into biomass during plant growth, and the 

17 International Reference Life Cycle Data System http://eplca.jrc.ec.europa.eu/?page_id=86 

 
                                                      
 
subsequent release of the CO2 back into the atmosphere through processes such as 
biomass combustion are effectively excluded from the analysis. The rationale for doing 
this is that the emissions associated with both processes are the same, and that they 
therefore should balance each other out. However, in practice, this may not always be 
the case, although data in respect of the uptake processes is generally less robust than is 
the case for the processes involving the release of the biogenic CO2. 

Reflecting the updated thinking on this topic, the PEF methodology now assigns an 
emissions credit of -1 CO2eq for every tonne of carbon dioxide removed from the 
atmosphere during, for example the growth of a tree that will subsequently be used for 
pulp in a paper production process. The release of biogenic carbon dioxide during a 
combustion process occurring as part of the manufacturing process would similarly be 
accounted for within the emissions inventory. 

It is a requirement for PEF studies that removals and emissions of biogenic carbon 
sources shall be kept separated in the Resource Use and Emissions Profile. In this study, 
biogenic, fossil and an overall combined (fossil and biogenic) carbon value are used. 

7.3 

Environmental Footprint Impact Categories and 
Assessment Methods 

Environmental footprint (EF) impact categories are the specific environmental impact 
categories that are considered in a PEF study. As specified in the PEF guidance all of the 
default EF categories and their assessment methods will be used. The process for 
exclusion of certain categories would normally take place after the initial screening 
study. This phase would highlight the most important EF impact categories. However, as 
this is a screening study, there is at this stage in the analysis no justification for excluding 
any of these categories. The EF categories are detailed along with how each one is 
assessed in appendix A.2.2 and summary is shown in Table 4. 

As identified in the previous section, the additional category of ‘climate change – 
biogenic’ is also included in the analysis. This is based on the precedent set by the PEF 
Category Rules (PEFCR)18 for intermediate paper products (e.g. newspaper that has not 
yet been printed on) which has included this category in its draft proposals.19 

The uptake/emissions which have to be used for modelling this indicator are: ‘carbon 
dioxide, resources from air’, ‘carbon dioxide (biogenic)’, ‘methane (biogenic)’ and 
‘nitrous oxide’. All other climate change impacts are included within the ‘climate change 
– fossil’ category, and output from the two categories is then combined to form an 
aggregated ‘climate change – overall’ indicator. 

18 The PEFCR is a set a rules that are used to run PEF studies that are aimed at specific products and allow 
these products to be compared effectively and fairly. These have been developed for many industries 
during a pilot phase over the past 2-3 years. 
19 Technical Secretariat for the Intermediate Paper Product (2015) Product Environmental Footprint (PEF) 
Category Rules (PEFCR) Pilot Intermediate Paper Product, Report for European Commission, October 2015 

22 

 
 
                                                      
 
For the intermediate paper products, the PEFCR only includes ‘cradle to gate’ processes 
(i.e. not end of life) and therefore it is more important to account for the initial biogenic 
CO2 uptake stage (relating to the incorporation of atmospheric CO2 into plant material 
during plant growth). The use of such an approach also results in the need to account for 
the carbon balance of the different products, as will be discussed further in Section 9.2.  

Table 4 - Environmental footprint (EF) Impact Categories 

EF Impact Categories 

Climate Change  

Ozone Depletion  

Ecotoxicity for aquatic fresh water  

Human Toxicity - cancer effects 

Human Toxicity – non-cancer effects  

Particulate Matter/Respiratory Inorganics  

Ionising Radiation – human health effects 

Photochemical Ozone Formation  

Acidification  

Eutrophication – terrestrial  

Eutrophication – aquatic  

Resource Depletion – water 

Resource Depletion– mineral, fossil 

Land Use 

7.4 

Assumptions 

Measurement Description 

The emissions of greenhouse gases can 
impact on global climate 
The emissions ozone depleting substances 
and their effect on the ozone layer 
The emissions of substances and their effect 
on freshwater ecosystems 
The emission of carcinogenic substances 
The emission of hazardous substances with 
negative human effects   
The emissions of substances like to 
respiratory illnesses 
Exposure to radiation and its health effects 
on humans 
The emission of air pollutants commonly 
known as ‘smog’ 
The emission of substances which increases 
the acidity of rain 
The increase in nutrients which can upset the 
natural balance on land  
The increase in nutrients which can upset the 
natural balance in water 
The amount of water used 
The amount of non-renewable energy and 
minerals used 
The increase or decrease in soil quality 

The following sections detail the core assumptions that have been used to generate the 
LCA model. 

7.4.1 

Transport 

Table 5 shows the assumptions that have been used for the transportation of the bags to 
the end user. As this study focuses on a European perspective (rather than a specific 

 
 
country), the ‘local’ distances are based on manufacture and movement of the product 
within a Member State. An estimate of 300 km is given for local road transport although 
this will vary greatly in practice. Both PCL and PLA are manufactured in centralised 
European plants and therefore the 800 km of estimated transport distance reflects the 
potential transportation to different countries. Although the manufacturing data for PLA 
is taken from the Natureworks plant in the US, it has been reported that PLA is now 
produced on a large scale within Europe20; therefore transport is also assumed to be 800 
km by road on average for these bags.  

Table 5 – Transportation Assumptions 

Material 

PCL 

HDPE 

Paper 

PLA 

Origin 

Italy 

Local 

Local 

Europe 

Distance 

Transport Type 

800 km 

300 km  

300 km 

800 km 

Road 

Road 

Road 

Road 

It is also assumed that each of the bags will be transported 30km to an appropriate 
waste/recycling depot at the end of its life. In practice the transport will vary greatly 
depending upon the local infrastructure and recycled materials will usually travel further 
(as processing facilities are usually centralised). However, transport at the end of life is 
unlikely to be the defining factor in the results, therefore a standard distance is 
assumed.   

7.4.2 

End of life 

Table 6 shows that baseline scenario for the end of life. Some studies have used single 
treatment scenarios (i.e. all products go to incineration) to represent the best case 
disposal method for each material. This is useful from a policy point of view as a means 
to promote different disposal methods; however, it is unlikely that the optimum material 
and disposal method for very lightweight plastic carrier bags will be particularly 
influential on European waste policy. It is for this reason that the baseline scenario is 
constructed upon a real-life projection of the average European split between landfill 
and incineration in 2020.21 It should be recognised that this split is considerably different 
to the assumptions used in many of the existing reviewed studies which have assumed 
10 – 20% incineration rather than the assumption of 60% used here — reflecting the 

20 http://www.bio-based.eu/market_study/media/files/13-07-24PRMarketStudynova.pdf  
21 Eunomia Research & Consulting (2015) Support to the Waste Targets Review: Analysis of New Policy 
Options, October 2015, 
http://ec.europa.eu/environment/waste/pdf/Analysis%20of%20New%20Policy%20Options%20Eunomia%
20report%202015.pdf  

24 

 
 
 
 
 
                                                      
 
ongoing move towards incineration from landfilling within Europe as a result of policy. 
This has some impact on the results which are discussed further in Section 8.0.  

Table 6 – Baseline End of Life Scenario 

Material 

Incineration 

Landfill 

Composting/anaerobic 
digestion 

Recycling 

PCL 

HDPE 

Paper 

PLA 

Notes: 

30% 

60% 

30% 

30% 

20% 

40% 

20% 

20% 

30% 

30% 

72%1  

1.  Although 72% goes to recycling 14% is estimated to be lost during the recovery and recycling 

process due to contamination and process losses. 

It is assumed that HDPE very lightweight plastic carrier bags will only go to residual 
treatment. Whilst previous studies have assumed a small amount of lightweight plastic 
carrier bags goes to recycling, the scenario for very lightweight plastic carrier bags will be 
different and it is less likely that they will be recycled in practice. 

The default assumption for PCL and PLA is 30% to anaerobic digestion /composting. This 
represents the end of life scenario for second use as an organic household waste bin 
liner. There is no specific data available to suggest what proportion may be used as 
organic household waste bin liner in reality, but participation of organic household waste 
is generally fairly low at present and there are no specific organic household waste 
collection targets at a European level. A 30% rate for second use as organic household 
waste bin liner therefore represents an optimistic scenario for 2020. As part of the 
sensitivity analysis the minimum level for second use as an organic household waste bin 
liner that allows for compostable plastic bags to be a viable alternative will be calculated 
from an environmental point of view. 

The default scenario for paper is to assume that 72% will be recycled, based on 2014 
data on European paper recycling rates from CEPI.22 This figure has stayed fairly static for 
the past 3 – 4 years and therefore is not expected to increase greatly by 2020 although 
packaging targets begin in 2020 so some countries may improve on this slightly. 

22 CEPI (2015) Paper Recycling Monitoring Report 2014, October 2015 

 
 
 
 
 
 
 
 
                                                      
 
European waste management data23 suggests that 14% of paper that is collected is lost 
during the sorting and recycling process, therefore 58% of the paper will be used to 
manufacture new paper products.  

As has been previously highlighted, there is no agreed method for calculating littering 
impacts and therefore it is difficult to assess using life cycle assessment methodology. As 
a consequence there are no default EF categories which can be used to calculate these 
impacts using the PEF methodology. As such, these impacts have not been considered 
within the main LCA study. The comparative environmental impacts of littering of the 
different materials is therefore addressed independently in Section 10.0. 

23 Extended Producer Responsibility Alliance (2014) The Effects of the Proposed EU Packaging Waste Policy 
on Waste Management Practice: A Feasibility Study, October 2014, 
www.expra.eu/downloads/expra_20141004_f_UGGge.pdf 

26 

 
 
 
                                                      
 
8.0  Resource and Emission Profile 

A resource and emissions profile24 is an inventory of all the material and energy 
resources that form the inputs and outputs into air water and soil. This is where the data 
for all the processes is compiled.  

For this study, the software SimaPro is used to build up the database of resources and 
emissions for each of the products. The software provides a way of taking the secondary 
emissions data from various databases and compiling it into a manageable form to be 
used in the environmental impact assessment. 

As this study is intended to be limited to the use of secondary emissions data from 
publically available data (i.e. primary data is not collected for the individual processes), 
only the first step of the process for carrying out the Resource and Emission Profile is 
undertaken (see Figure 2). This first step is known as the ‘screening step’ which is a 
recommended step to help focus data collection activities and data quality priorities.  

Figure 2 – Two Steps for Carrying Out the Resource and Emissions Profile 

Source: Product Environmental Footprint (PEF) Guide 

8.1 

Data Sources 

As identified, the data used to build the Resource and Emission Profile comes from third 
party; this has been combined with the assumptions outlined in Section 7.4. It is 
important to recognise that none of the raw data used in the Resource and Emission 
Profile comes from the reviewed literature in Appendix A.1.0 (although the literature has 
been used to inform the structure of the model and some of the assumptions). Although 
the data sources are often specified in the literature, the raw data is not usually 

24 The same as the ’life cycle inventory’ in ISO 14044 

 
 
 
 
                                                      
 
presented in the reports due to its complex nature and due to this data typically being 
obtained from a proprietary source. 

The data used in this study comes from varied sources and the exact datasets are 
detailed in Appendix A.2.1. The primary source is the Ecoinvent25 database. This is an 
internationally recognised database of materials and processes, where independent 
research supported by industry has been used to collate the various inputs and outputs. 
The database is often used when there is no primary data available, or as in this case, 
being screening study is being performed. Where the latter is the case, the use of 
secondary data is considered to be justified within the methodology as a first step in 
assessing the anticipated performance of the product or product(s). The data is based on 
industry averages and is usually location specific. Many of the studies in the literature 
review relied, at least in part, on Ecoinvent as a supplementary source of data. 

For this study, data for the production for HDPE, paper, PCL and PLA have all been taken 
from Ecoinvent. The Ecoinvent database itself often uses data from industry sources 
where available and this is the case for HDPE, PCL and PLA. HDPE data has been sourced 
from publically available data from Plastics Europe’s Ecoprofiles.26 This is a regularly 
updated dataset which uses averaged data from across Europe. PCL data comes from 
Novamont who are the producers of PCL with starch to form their product Mater-Bi.27  

The dataset within Ecoinvent is based upon an Environmental Product Declaration (EPD) 
from 2004; as part of this study the project team contacted Novamont for an updated 
EPD. This information was provided for the year 2010, and the data showed that the 
starch proportion had been increased; the Ecoinvent dataset was therefore modified to 
reflect this change. The data in Ecoinvent for PLA was taken from Natureworks28 who are 
a global producer of PLA. 

Another key data source is The European reference Life Cycle Database (ELCD)29 which is 
administered by the Joint Research Centre on behalf of the European Commission. This 
database is similar in nature to Ecoinvent but is smaller in scope and focuses on datasets 
specific to the European situation. Where appropriate, the ELCD is used; in most cases 
the use is restricted to transport and end of life processes which are more general and 
non-industry specific in nature. 

25 http://www.ecoinvent.org/  
26 http://www.plasticseurope.org/plastics-sustainability-14017/eco-profiles.aspx  
27 http://www.novamont.com/eng/mater-bi  
28 http://www.natureworksllc.com/  
29 http://eplca.jrc.ec.europa.eu/?page_id=126  

28 

 
 
 
 
                                                      
 
9.0  Environmental Footprint Impact 

Assessment - Results 

9.1 

Interpreting the Results from the Study 

The environmental footprint (EF) impact assessment includes the classification and 
characterisation of the Product Environmental Footprint flows in the resource use and 
emissions profile. This maps all emissions and resource use to the EF categories specified 
by the PEF guidelines and recommended by the ILCD.30  

Firstly, each substance is classified by whether it has an impact under one of the EF 
categories. A characterisation factor (CF) is then applied to each flow.  

For example, fossil CO2 and methane emissions are classified under the EF category 
‘climate change’. The methodology for the calculation of climate change impacts gives 
CO2 a classification factor of 1 (1kg CO2 = 1kg CO2 equivalent) whereas methane 
emissions are given 25 (1kg CH4 = 25kg CO2e), based on the increase impact each kg of 
methane has. All substances and emissions are characterised in this way using the most 
robust methodologies available currently. 

The full list of environmental footprint (EF) categories along with their descriptions and 
sources are provided in Appendix A.2.1.  

There are two sets of results from this study: 

1)  Results comparisons between the different products against the different 

environmental footprint categories defined by the PEF. Results in the central case 
are presented in Section 9.2. Sensitivities are further explored in Section 9.3. 
2)  For each footprint category, a breakdown of the results for each product by life 

cycle stage is presented in Appendix A.3.0. 

In both cases, as the environmental footprint (EF) categories address different issues and 
use different units it is not possible to show results for them on the same graph without 
undertaking a further analytical step during which an attempt is made to mathematically 
scale the results so that they can be expressed in equivalent terms31. Therefore, results 
are shown in terms of the contribution of a process or lifecycle stage towards the overall 
impact of that particular EF category.  

30 International Reference Life Cycle Data System http://eplca.jrc.ec.europa.eu/?page_id=86  
31 This step is known as normalising the results and it is not a compulsory part of PEF. As, there is no 
scientific consensus on how to undertake this step, normalisation factors have not been applied to the 
results of this study. 

 
                                                      
 
In the PEF methodology, no EF category is deemed to be more important than another 
and no weighting is given. Beyond the PEF, however, the relative importance of each EF 
category is determined by the priorities the country or organisation that may make 
decisions based on the results. Environmental policy at a national and international level 
reflects these priorities: thus there are emissions reductions targets for climate change 
impacts at both a European and national level, and emissions of other key pollutants 
such as particulates are also controlled based on internationally agreed legislation. 

It is also important to recognise that not all EF categories are deemed to be equal in 
terms of their scientific development, reflecting strength of scientific certainty on the 
causal relationships linking emissions, for example, to impacts on human health and the 
natural environment. For example, considerable uncertainty surrounds the calculation of 
toxicity impacts within life cycle assessment studies.  

To a certain extent improvements in datasets such as those used in life cycle 
assessments proceed on an iterative basis, and the strength of the evidence base and 
the development of policy are interlinked. Where there are targets in place, emissions 
are more likely to be measured throughout the process, further improving the 
robustness of the data associated with these categories within the life cycle datasets. 
Policy is also more likely to be developed in response to a specific problem where data 
has been found to unequivocally demonstrate the problem exists, although in some 
cases concern is sufficient such that the precautionary principle is employed to control 
impacts on the basis of output from more uncertain datasets. 

Reflecting these scientific uncertainties, Appendix A.2.1 shows the relative 
recommendation levels given to each EF category. This shows that only three categories 
are considered to have data of a sufficient quality such that is deemed to reach a 
satisfactory level: climate change, ozone depletion, and particulate matter/respiratory 
organics, with European environmental policy being relatively well developed in each of 
these three areas. 

Figure 3 shows an example of a comparison of the overall results between two products. 
In this comparison, the bar for each EF category set at +100% shows which product 
performs the worst. In some cases, the most significant impact is a net benefit, and in 
such a case the bar is set at -100%. This is the case where the most significant impact is a 
net benefit as a result of offset production impacts, resulting from the allocation 
processes set out in Section 7.2.1.  

Very generally, the product with the most bars at +100% across the different categories 
can initially—before further in depth analysis has been conducted as part of a full PEF 
study —be considered to have a higher environmental impact. In practice, the quality 
and accuracy of the data is such that no decisions should be based upon marginal 
differences in results in the absence of more work being undertaken to increase the 
accuracy of that particular result (e.g. identifying the substance or process emissions that 
contribute to the difference and confirming their accuracy using direct primary source 
data). Reflecting this, the difference between the two bars should only considered 
significant if it is greater than 10% — 20%. 

30 

 
 
Figure 4 shows an example of the graph used to illustrate the breakdown of the results 
for each product within a specific EF category. Each EF category adds up to 100% and the 
graph shows how the different life stages contribute to the total. In this case it shows 
that manufacturing is the dominant lifecycle stage in almost all EF categories. 

Figure 3 – Product Comparison Example 

Insignificant difference 

Significant 
Difference 

Figure 4 – Example of Results Breakdown Graph 

= 100% 

= 100% 

 
 
 
 
 
9.2 

Comparison of Product Performance – Central Case 

The results from the full life cycle EF Impact Assessments of each material are shown in 
Figure 5; in this case the graph shows the results against all default categories. HDPE is 
highlighted as the baseline material that all others are compared against; it outperforms 
the other materials in most cases in all categories except for biogenic climate change. 
The results for biogenic climate change have the effect of reducing the overall climate 
change impacts for paper and PLA to below that of HDPE, as the overall climate change 
indicator is a combination of the fossil and biogenic indicators.   

Figure 5 – Comparative Life Cycle Assessment Results – all Categories 

These results are also shown in Table 7. With HDPE as the benchmark, all other materials 
are scored relative to their impact in each EF category. Any value that is below HDPE 
(<100%) is shown in green; these are the categories where the other materials 
outperform HDPE. Paper does better than HDPE in categories in comparison to the 
compostable plastic bags; it is the only one that improves in Ionizing radiation. Values 
between 100—200% are shown in orange; this indicates categories in which the 
materials perform worse than HDPE which could possibly be improved with a change of 
assumptions or a process improvement. Finally, values >200% (more than twice the 
impact of HDPE) are shown in red. 

32 

 
 
 
 
 
Table 7 - Comparative Life Cycle Assessment Results 

EF Category 

HDPE 

PCL 

Paper 

Climate change - Overall 

Climate Change - Biogenic 

Climate change - Fossil 

Ozone depletion 

Human toxicity, non-cancer effects 

Human toxicity, cancer effects 

Particulate matter 

Ionizing radiation HH 

Photochemical ozone formation 

Acidification 

Terrestrial eutrophication 

Freshwater eutrophication 

Marine eutrophication 

Freshwater ecotoxicity 

Land use 

Water resource depletion 

100% 

100% 

100% 

100% 

100% 

100% 

100% 

100% 

100% 

100% 

100% 

100% 

100% 

100% 

100% 

100% 

PLA 

81% 

99% 

35% 

-311% 

-1240% 

-1184% 

108% 

587% 

63% 

475% 

553% 

1515% 

259% 

134% 

464% 

1583% 

175% 

151% 

629% 

358% 

187% 

699% 

319% 

59% 

203% 

544% 

329% 

126% 

378% 

204% 

1059% 

2857% 

109% 

502% 

202% 

268% 

486% 

229% 

198% 

717% 

392% 

242% 

627% 

421% 

918% 

117% 

224% 

1033% 

Mineral, fossil & ren resource depletion 

100% 

348% 

2594% 

357% 

Notes: 

Green = Improvement compared with HDPE 

Orange = Worse than HDPE 

Purple = Much worse than HDPE 

 
 
 
 
 
The result of using the PEF framework as a basis for assessing environmental impacts is 
that a large number of categories need to be considered, which can make it difficult to 
draw conclusions. As was indicated in Section 9.1, however, the level of scientific 
certainty varies across the categories. Figure 6 therefore presents the results for the 
categories where the data is considered to be the most robust. This graph simplifies the 
pattern seen in Figure 5. The simplified results show that paper bags clearly outperform 
the others in respect of climate change impacts but are the worst performers by some 
distance in respect of particulate matter emissions, whilst impacts for ozone depletion 
are also relatively poor in comparison to HDPE.  

The compostable plastic bags perform relatively well in respect of particulate matter 
emissions particularly in comparison to paper, but do less well against the other 
categories. Where performance in respect of climate change is concerned, PLA and PCL 
perform somewhat differently; PLA bags show significant fossil climate change impacts 
as well as significant biogenic benefits, whilst PCL bags show less of a benefit in respect 
of the biogenic climate change impact. This results from the composition of the bags; 
whereas the biogenic carbon content of PLA bags is high (close to 100%), the PCL bags 
are made using a mixture of synthetic and biogenic feedstocks, such that the biogenic 
carbon content is only around 60%. The compostable plastic bags are the worst 
performers for ozone depletion, although in the case of PLA the performance is only 
slightly worse than that of the paper bag. 

Figure 6 -   Comparative Life cycle Results – Robust Categories Only 

34 

 
 
 
 
The results for the non-climate change categories are influenced to a significant extent 
by the type and quantity of energy used in the different production processes. A 
significant proportion of the energy used to produce the HDPE bags is from electricity 
generation. In contrast, the other bags use significant quantities of bio-energy (in the 
case of paper) and heat energy from district heating systems.  

Further detailed discussion is provided in Appendix A.3.0  which provides a breakdown 
of results for each material by life cycle stage. This gives further information on which 
lifecycle stages are important for each material, but is left out of the main report body as 
the primary focus is the comparison between materials. 

Figure 7 – Climate Change Comparison 

Figure 7 shows climate change impacts on their own. In this case, the absolute values in 
kg CO2 equivalent are shown and the graph shows the relative contribution of biogenic 
and fossil CO2. Biogenic climate change emissions appear on the graph for the bio-plastic 
bags and those made of paper. That net negative biogenic emissions appear in the 
inventory suggests the following possible scenarios: 

  The biogenic carbon has been sequestered—this may be the case for 

recycling of paper; and 

  The limitations of using secondary datasets to model biogenic carbon mass 
flow, such that the carbon flows across the different processes modelled 
within the database are not entirely consistent with one another. 

 
 
 
 
 
The second point is related to the fact that the modelled uptake of biogenic carbon 
during crop growth may not always equal that which is emitted at the end of life stage, 
as the datasets used for each one come from different sources. This is partially due to 
surrogate end of life processes being used where no process otherwise exists in the 
database for a specific product —substituting paper32 in incineration and landfill for bio-
based plastics, for example—and also due to the fact that emissions for waste processes 
are often measured and may therefore be more accurate, whereas the uptake during 
crop growth can only be estimated. Balancing the biogenic carbon across the different 
processes within the database is therefore somewhat problematic; undertaking such an 
exercise was beyond the scope of this study. For reasonable comparisons with existing 
studies the value for fossil carbon can be used on its own. 

9.3 

Sensitivity Analysis 

9.3.1 

Second use as organic household waste bin liner and 
Recycling Scenarios 

As seen in Table 7, both PLA and PCL have greater environmental impacts in most of the 
EF categories. The baseline scenario uses the assumption that 30% of the bags will be 
used a second time, as an organic household waste bin liner. The following shows how 
increasing this proportion will affect the results in order to identify whether either 
material would become a more preferable alternative to HDPE under such a scenario. 

Figure 8 shows the EF categories that, with a second use as organic household waste bin 
liner of 30%, perform worse than HDPE. The results show that overall climate change 
impacts begin to become less than HDPE at around 40% second use as organic 
household waste bin liner and water resource depletion at around 50%.  

Biogenic carbon impacts are seen to increase, as when second use as organic household 
waste bin liner is increased, this results in a larger offset associated with the production 
of organic household waste bags. A reduction in the need for organic household waste 
bags to be produced results in a smaller quantity of biogenic CO2 uptake during the 
growth of the crop to produce the feedstock for the bags. There continues to be the 
release of biogenic CO2 during waste treatment processes resulting in a net increase in 
biogenic CO2. This is offset however, by the reduction in process emissions, and as a 
result the overall climate change impacts are reduced. 

32 As noted in other LCA studies, paper is a reasonable substitute for modelling the degradation processes 
of the compostable plastic bags, but will not be 100% accurate in terms of the carbon mass balance. 

36 

 
 
 
                                                      
 
Figure 8 – PCL Bag second use as organic household waste bin liner rate 
from 40 – 80% 

Table 8 – Sensitivity of PCL Results to second use as organic household 
waste bin liner rate 

EF Category 

Climate change - Overall 
Climate Change - Biogenic 
Climate change - Fossil 
Ozone depletion 
Human toxicity, non-cancer effects 
Human toxicity, cancer effects 
Particulate matter 
Ionizing radiation HH 
Photochemical ozone formation 
Acidification 
Terrestrial eutrophication 
Freshwater eutrophication 
Marine eutrophication 
Freshwater ecotoxicity 
Land use 
Water resource depletion 
Mineral, fossil & ren resource depletion 

HDPE 

100% 
100% 
100% 
100% 
100% 
100% 
100% 
100% 
100% 
100% 
100% 
100% 
100% 
100% 
100% 
100% 
100% 

40% 

92% 
271% 
87% 
505% 
475% 
222% 
403% 
150% 
133% 
550% 
318% 
160% 
605% 
274% 
927% 
101% 

299% 

60% 

76% 
857% 
59% 
340% 
319% 
149% 
281% 
100% 
96% 
392% 
238% 
107% 
417% 
184% 
663% 
67% 

200% 

80% 

61% 
1442% 
30% 
176% 
163% 
76% 
160% 
50% 
60% 
233% 
158% 
54% 
229% 
94% 
398% 
34% 

102% 

 
 
 
 
As can be seen in Table 8 PCL bags become a viable environmental replacement for 
HDPE in the majority of categories when the rate of second use as organic household 
waste bin liner is higher than 80%. It is unlikely such a scenario could be achieved across 
a whole country particularly within the current policy framework, although certain areas 
within a country that have a high performing organic household waste collection service 
might reach this level of performance. 

Figure 9 shows this process also applied to PLA. Again, we see that climate change 
impacts remain improved over HDPE. The remainder of the EF categories are 
considerably worse at 40% and begin to improve against HDPE by 80%. As was indicated 
for PCL, this is an unlikely scenario in respect of the performance of a country as a whole. 

Figure 9 - PLA Bag second use as organic household waste bin liner rate 
from 40 – 80% 

Table 9 shows that seven of the 17 EF categories are improved compared to HDPE when 
80% of the bags are used a second time as organic household waste bin liner. Both 
freshwater ecotoxicity and resource depletion are close enough to be considered similar.  

38 

 
 
 
 
 
 
 
 
 
 
 
 
Table 9 – Sensitivity of PLA Results to second use as organic household 
waste bin liner rate 

EF Category 
Climate change - Overall 
Climate Change - Biogenic 
Climate change - Fossil 
Ozone depletion 
Human toxicity, non-cancer effects 
Human toxicity, cancer effects 
Particulate matter 
Ionizing radiation HH 
Photochemical ozone formation 
Acidification 
Terrestrial eutrophication 
Freshwater eutrophication 
Marine eutrophication 
Freshwater ecotoxicity 
Land use 
Water resource depletion 
Mineral, fossil & ren resource depletion 

HDPE 
100% 
100% 
100% 
100% 
100% 
100% 
100% 
100% 
100% 
100% 
100% 
100% 
100% 
100% 
100% 
100% 
100% 

40% 
76% 
-482% 
88% 
432% 
174% 
230% 
422% 
196% 
173% 
625% 
347% 
207% 
544% 
361% 
806% 
885% 
306% 

60% 
65% 
349% 
59% 
292% 
119% 
154% 
294% 
131% 
123% 
441% 
258% 
138% 
376% 
242% 
582% 
590% 
206% 

80% 
55% 
1181% 
30% 
151% 
63% 
79% 
166% 
65% 
73% 
258% 
168% 
70% 
208% 
123% 
357% 
295% 
105% 

Figure 10 shows how the assumed recycling rate of paper affects the results. Whilst 
overall carbon emissions are affected very little by the increase in recycling, all of the 
other EF categories see relatively large changes. If no recycling is assumed (and also with 
the raw material assumed to have no recycled content) the paper bag performs worse in 
all other categories. With 100% of the paper collected for recycling—and still assuming 
14% process losses—three of the EF categories are reduced enough such that there is an 
improvement in the performance of paper relative to HDPE, namely the categories of 
human toxicity (cancer effects), ionizing radiation and freshwater eutrophication.  

 
 
 
Figure 10 - Paper Bag Recycling Rate from 0 – 100% 

9.3.2 

Organic household Waste Bin Liner Size 

Whilst the sizes of the bags have been kept uniform throughout this study in order to 
provide direct comparisons, the bags used for fruit and vegetables may not be the same 
size as those used for organic household waste bins. The smallest size that is in regular 
use in the UK is designed to fit a 5 litre bin.33 The surface area of this bag (360mm x 
350mm) is around 30% greater than the bag used as the baseline in this study. This 
difference would vary in practice as different countries (and individual super markets) 
may use larger or smaller sizes as standard. Figure 11 shows the impact of this change on 
the PCL bag with all other assumptions remaining the same. The PCL bag now performs 
much worse in all EF categories when compared with the HDPE.  

33 http://www.caddiesandliners.co.uk/products/organic household-waste-liners-corn-starch-biobag/56-
litre-constarch-biobag-kitchen-caddy-liner-from-as-little-as-260-per-roll  

40 

 
 
 
 
 
                                                      
 
Figure 11 – Larger Organic household waste Bin Liner (Mater – Bi)  

9.4 

Results Interpretation and Discussion 

9.4.1 

Comparison with other studies 

There are two key differences in the primary data collected as part of this study which 
differentiate the results. 

The first key difference is that this study considers that the paper bag performs better 
from a climate change perspective than many other studies did so far. This is due to: 

1)  The amount of material assumed to be only three times (by weight) that of HDPE 

rather than 8 – 9 times in other studies, and; 

2)  Assigning a value to biogenic carbon which essentially credits carbon 

sequestration. 

Most studies that have considered the paper bag assume that it will be a very thick 
gauge with reinforcements. It is debatable whether the extra strength is required for 
shopping bags, however, it is demonstrated in practice that this is not required for the 
equivalent very lightweight plastic carrier bag.  

The issue of biogenic carbon is one that is also not fully addressed in other studies and it 
is also beyond the scope of this limited assessment to identify and collect the necessary 
data to allow these emissions/sinks to be fully investigated (as was indicated in Section 
9.2). As most datasets are not interdependent - and up until recently biogenic carbon 
was mostly ignored - it is difficult to obtain a full biogenic carbon mass flow. Therefore it 
is not always possible to accurately measure both the amount absorbed during crop 

 
 
 
growth and particularly the amount emitted during end of life processes. This illustrates 
the limitations regarding the use of secondary data and the dataset substitution. 

The second key difference are the changes in the end of life practices over the last 10 
years. The ongoing move to incineration from landfill has had the following impacts: 

  HDPE performs worse as its fossil carbon is emitted during incineration; 
  Bio-based products can perform better as they emit (biogenic) carbon rather 

than the more harmful methane during landfill degradation. 

Both the assumptions on the weight of paper bags and the changes in the end of life 
stages have resulted in paper appearing to become a more viable option in climate 
change terms than has been concluded in previous studies. It still falls short in most of 
the other EF categories, however. 

9.4.2 

Use of Secondary Data 

Due to the limited scope of this study secondary data was utilised throughout. 

9.4.2.1  Data on Manufacturing Processes 

The raw material production and manufacturing stage was found to have the most 
environmental impact for each type of bag considered in this study. The quality and 
accuracy of the manufacturing data is therefore of critical importance. In the case of this 
study, each of the raw material data source was different and has the potential to also 
be variable in scope and depth. The two data sources for compostable plastics 
(Novamont for PCL and Natureworks for PLA) are based on proprietary processes and 
whilst Novamont provided an EPD34 for their product a full process inventory was not 
possible due to confidentiality issues. The comparative results between products are 
close enough that small changes to the inventory of the production process could have a 
large difference and therefore more accurate data should be sought before basing policy 
decisions on the outcome. 

Data for HDPE is certainly the most recent and includes elements of renewable energies 
which do not appear in either of the other compostable plastics. From industry 
discussions we know that bio-based manufacturers are certainly using more renewable 
energy. This will undoubtedly improve their climate change impacts but may have 
adverse impacts in other areas. 

Changes were made to the PCL (Mater-Bi) data set based on Novamont’s latest 
Environmental Product Declaration (EPD) which saw an increase in the bio content from 
around 30% to 60%. Whilst this improved some EF categories (Climate change) some 
others were adversely affected by the increase in agricultural activity (Eutrophication). 

34 EPD – Environmental Product Declaration; A document that provides an abridged version of an LCA 
study conducted on a product. 

42 

 
 
                                                      
 
9.4.2.2 

Energy Mixes 

Many of the end of life datasets in Ecoinvent/ELCD use older European average energy 
mixes to account for the offset of energy generation. These datasets include a higher 
proportion of coal than is likely to be the case which makes the offset look better than it 
otherwise would be.  

Another related issue is the need to use European average data, which is both difficult to 
judge for its accuracy and may not be necessarily representative of the best case within 
different countries.  

9.4.2.3  Carbon Balance 

As discussed in Section 9.2 the secondary data is not particularly compatible with a 
carbon mass balance approach which is now required to ensure that the biogenic carbon 
emissions are now correctly modelled (i.e. what goes in, must come out). In order to 
improve this aspect specific data would need to be gathered that properly accounts for 
the specific scenarios being assessed. Generalised and averaged data derived from 
secondary datasets will never fully balance. As such, a study undertaken in line with the 
‘screening’ approach can only give an overall indication for the expected results, rather 
than a definitive answer.  

9.4.3 

Differences in Anaerobic Digestion across Europe 

An increase in the use of compostable plastic bags may also have an impact in some 
countries on the operation of anaerobic digestion facilities used to treat source 
segregated organic household waste. Although the types of bag considered in this study 
are compostable according to the European standard EN 13432, these materials degrade 
far less readily under anaerobic conditions. The current practice in some countries such 
as Italy and Germany is for solid output from the anaerobic digestion process to be 
subsequently treated in a composting process. Where such a practice takes place, the 
increased use of these bags should not present too much of a problem provided 
sufficient time is allowed for the composting of this material to take place. However, in 
some countries such as the UK, the post-digestion composting step is not typically 
undertaken. Under these circumstances, the increased use of compostable plastic bags 
may result in plant operators having difficulty in reaching the quality protocol for 
digestate, due to the visible remains of the un-degraded bags being present in the 
digestate. This might require some operators to remove the bags prior to digestion, with 
the material potentially being sent for disposal. 

 
 
 
10.0  Littering 

Littering is considered as a separate part of this study due to its incompatibility with 
current LCA methodology. It is often argued that plastic bag littering is a social issue and 
is a matter of perception. However, in recent years it has become clear that plastic 
entering the marine environment is of concern with respect to potential impacts on 
biodiversity, indicating that an assessment of this type of environmental impacts is not 
unwarranted – even if such impacts cannot readily be assessed using LCA. Although 
research is still being conducted in various institutions around the world on this topic it is 
still not possible to quantify these impacts with any degree of certainty using current 
assessment methodologies. 

Most LCA studies agree that it is not known what proportion of plastic bags will become 
litter. A figure of 0.5% is often used as an estimate for this. There is also discussion 
regarding whether the more widespread use of biodegradable bags will also promote 
littering, as littering may be perceived as “acceptable” assuming the bag biodegrades. 
Again, this is not substantiated by any direct data sources. All of the discussion is also 
focused on the larger carrier bags which are arguably more likely to be littered outside of 
the home than a very lightweight plastic carrier bag. As very lightweight plastic carrier 
bags are primarily used in transportation of fruit and vegetables from the supermarket 
to the home, there is less likelihood of littering. Any littering impact must therefore not 
be overstated.  

In comparing the impact of alternative materials for very lightweight plastic carrier bags 
it is assumed the littering rate would be the same for all types of bag as there is no firm 
evidence to suggest any difference resulting from the material used. The key differences 
therefore lie in the rate of degradation in both the terrestrial and marine environments. 

10.1 

Environmental Biodegradation  

In 2012 California State University35 conducted a marine biodegradation test using the 
test standard ASTM D708136 on a number of bio-based materials including PLA, with 
LDPE used as a control. They found that PLA degraded by 8.4% in this environment, 
whilst LDPE degraded by 5.6% over the course of one year. 

There is little evidence to suggest that PLA will degrade readily in soil; a study into mulch 
films found negligible degradation for the material over the course of 30 weeks.37 

35 California State University (2012) PLA and PHA Biodegradation in the Marine Environment, Report for 
California Department of Resources Recycling and Recovery, March 2012 
36 http://www.astm.org/Standards/D7081.htm  
37 Dharmalingam, S., Hayes, D.G., Wadsworth, L.C., Dunlap, R.N., DeBruyn, J.M., Lee, J., and Wszelaki, A.L. 
(2015) Soil Degradation of Polylactic Acid/Polyhydroxyalkanoate-Based Nonwoven Mulches, Journal of 
Polymers and the Environment, Vol.23, No.3, pp.302–315 

44 

 
 
                                                      
 
Another Mediterranean study38 found that whilst the material became brittle and 
fragmented, very little biodegradation was observed after 11 months. The material 
appears to behave very much like HDPE and other fossil based plastics in this regard. 

The biodegradability of PCL in various environments has been studied in 2012 by 
Accinelli.39 Laboratory tests over the course of three months found that the material 
degraded in sea water and soil by 1.7% and 37% respectively. However, uncontrolled 
real life tests found that the material only degraded by 3.4% in soil. This was attributed 
to the soil conditions, moisture level and low microbial activity which demonstrates how 
variable and condition dependent biodegradation of these materials is in the open 
environment in comparison to laboratory conditions. Conversely, marine degradation 
was found to be higher in the field at 4.5% which was attributed to the action of the 
waves helping the break down the material. Novamont’s own in-house testing40 found 
that PCL degraded by 90% over 250 days when exposed to marine sediments. Whilst 
plastics may eventually become part of sediment, the testing by Novamont does not 
address the issue of biodegradation in the sea water itself; the bags still took twice as 
long as the cellulose control to reach the same level of degradation.  

Cellulose is used as the control comparison in many tests, as it is considered the 
benchmark for biodegradation. It is also a good indicator of how paper will behave in 
different environments. One such test41 performed to ASTM D7081 found that kraft 
paper degraded by 33% in 180 days. 

Table 10 provides a summary of the degradability of each material in terrestrial and 
marine environments.  

Table 10 – Degradation of Materials in Different Environments 

Environment 

HDPE 

Paper 

PCL 

PLA 

Terrestrial 
(soil) 

-  ~90% 100 days 

37% 90 days 

Negligible 330 
days 

Marine 

5.63% 365 days 

33% 180 days 

1.7% 90 days 

8.4% 365 days 

38 Rudnik, E., and Briassoulis, D. (2011) Degradation Behaviour of Poly(lactic Acid) Films and Fibres in Soil 
Under Mediterranean Field Conditions and Laboratory Simulations Testing, Industrial Crops and Products, 
Vol.33, No.3, pp.648–658 
39 Accinelli, C., Saccà, M.L., Mencarelli, M., and Vicari, A. (2012) Deterioration of Bioplastic Carrier Bags in 
the Environment and Assessment of a New Recycling Alternative, Chemosphere, Vol.89, No.2, pp.136–143 
40 http://materbi.com/en/wp-content/uploads/sites/2/2015/12/Scheda-biodegradazione-
marina_EN_MR.pdf  
41 Greene, J. Marine Biodegradation of PLA, PHA, and Bio-additive Polyethylene Based on ASTM D7081, 
accessed 12 May 2016, 
http://www.academia.edu/9639333/Marine_Biodegradation_of_PLA_PHA_and_Bio-
additive_Polyethylene_Based_on_ASTM_D7081 

 
                                                      
 
10.2 

Effects on Fauna 

The relevant literature has been reviewed in order to determine the relative impacts of 
paper and plastic bags on marine and terrestrial fauna. Such a review provides 
confirmation that evidence of negative impacts from plastic bags is readily available, 
albeit it is impossible to know the overall extent of the impact. By contrast, the literature 
does not identify similar environmental impacts arising from paper bags. 

Regarding ingestion, the most commonly ingested items recorded are small plastic 
fragments of a swallowable size, with plastic bags of particular concern for turtles and 
whales, and larger items of plastic waste including netting also of concern for baleen 
whales.42 The few reports of death in the toothed Pygmy Sperm Whale (Kogia breviceps) 
by ingestion of debris involved plastic bags, and plastic bags made up 2% of the items 
recovered from a Sperm Whale (Physeter macrocephalus) which also suffered the fatal 
consequences of ingestion.43 A review of ingestion reports from toothed whales dating 
from before 1990 states that plastic bags and sheeting were the predominant items 
ingested (62.5%).44  One study on fish ingestion stated that 22% of the items were small 
pieces of plastic bag.45 

There have been some indications - from turtles - that ingestion of plastic and latex are 
correlated with lower blood glucose levels, suggesting that they may be affecting 
nutrient absorption or metabolism.46  This might be a toxicological effect or it may be to 
do with inflammation, ulceration of the gut (this last, observed in dolphins which 
ingested plastic bags) or physical obstruction - reducing absorption of nutrients by the 
gut via reduced surface area. Cellular processes may also be implicated.47,48 

Ingestion of plastic and latex has also been linked to increased gas in the intestine in 
turtles, leading to impaired buoyancy control.49 

Data taken from the International Bottom Trawl Survey and the Clean Seas 
Environmental Monitoring Programme indicate that plastic bags make up 40% of all 
marine litter in the waters of the North East Atlantic.  The French research institute 

42 Butterworth, A., Clegg, I., and Bass, C. (2012) Untangled - Marine Debris: a global picture of the impact 
on animal welfare and of animal-focused solutions, Report for WSPA, 2012, http://www.wspa-
international.org/Images/Untangled%20Report_tcm25-32499.pdf 
43 Jacobsen, J.K., Massey, L., and Gulland, F. (2010) Fatal ingestion of floating net debris by two sperm 
whales (Physeter macrocephalus), Marine Pollution Bulletin, Vol.60, No.5, pp.765–767 
44 Simmonds, M.P. (2012) Cetaceans and Marine Debris: The Great Unknown, Journal of Marine Biology, 
Vol.2012 
45  Anastasopoulou, A., Mytilineou, C., Smith, C.J., and Papadopoulou, K.N. (2013) Plastic debris ingested by 
deep-water fish of the Ionian Sea (Eastern Mediterranean), Deep Sea Research Part I: Oceanographic 
Research Papers, Vol.74, pp.11–13 
46 Lutz, P.L. (1990) Studies on the ingestion of plastic and latex by sea turtles, 1990, 
http://swfsc.noaa.gov/publications/TM/SWFSC/NOAA-TM-NMFS-SWFSC-154_P719.PDF 
47 Meirelles, A.C.O. de, and Barros, H.M.D. do R. (2011) Plastic debris ingested by a rough-toothed dolphin, 
Steno bredanensis, stranded alive in northeastern Brazil., Biotemas, Vol.20, No.1, pp.127–131 
48 Bjorndal, K.A. (1997) Foraging Ecology and Nutrition of Sea Turtles (1997) 
49  Bjorndal, K.A. (1997) Foraging Ecology and Nutrition of Sea Turtles (1997) 

46 

 
 
                                                      
 
IFREMER has also found that in the Bay of Biscay most of the waste items found on the 
seabed were plastic (92%) and of those, 94% were plastic bags.50   

In terms of land-based impacts, it is noted by the UK’s Royal Society for the Prevention 
of Cruelty to Animals (RSPCA) that litter is a real hazard, stating that: 51 

Hedgehogs frequently get their heads stuck in tins, plastic bags, binders from 
drinks cans or plastic yoghurt pots. 

In contrast, a high level review of the literature has failed to identify evidence of impacts 
on wildlife – terrestrial or marine - through ingestion of, or entanglement with, paper 
bags. 

10.3 

Littering Impact factor 

Based on the preceding analysis of biodegradation and effects on fauna Table 11 and 
Table 12 present conservative estimates of littering impact factors for the marine and 
terrestrial environments respectively, for each of the types of bags under consideration 
in this study. These factors have been developed for all materials based on the 
degradation factors previously presented in Table 10.  

A qualitative assessment of the fauna impacts is included in both tables. Based on the 
evidence from the literature, it is sensible to conclude that all types of plastic (including 
the compostable plastic bags, which are here assumed to behave similarly to HDPE) will 
have a much greater impact on marine life than paper. The same is expected to be true 
for terrestrial fauna, although the evidence is more anecdotal; the terrestrial fauna 
impact factor is therefore estimated to be lower, reflecting the weight of evidence for 
the different types of materials. Figure 12 shows the two littering impacts combined for 
both types of environment; impacts are multiplied by the mass of each bag to give a 
total littering impact factor for each bag type.  

These results demonstrate that whilst the bio-materials may perform marginally better 
in terms of biodegradation, the increased mass of these bags results in a worsening of 
the overall littering performance in comparison to HDPE overall. In contrast - and despite 
having a larger mass than the other materials - paper is deemed to be unlikely to be a 
significant littering burden given that it is far more readily degradable (as is confirmed by 
the data previously presented in Table 10). 

50 Seas at Risk (2011) Commission Consults on Binning Plastic Bags, available at http://www.seas-at-
risk.org/news_n2.php?page=408 
51 See RSPCA (undated) Helping Hedgehogs in the Garden, available at 
https://www.google.co.uk/url?sa=t&rct=j&q=&esrc=s&source=web&cd=7&ved=0ahUKEwiQ9afC99TMAh
WaF8AKHczrDM4QFghGMAY&url=https%3A%2F%2Fwww.rspca.org.uk%2FImageLocator%2FLocateAsset%
3Fasset%3Ddocument%26assetId%3D1232736244256%26mode%3Dprd&usg=AFQjCNH8yesEMTEZS9I-
7lx_dy0daJxAwQ&bvm=bv.121658157,d.ZGg&cad=rja 

 
 
                                                      
 
 
Table 11 – Marine Littering Impacts 

Material 

HDPE 
Paper 
PCL 
PLA 

Marine degradation 
Factor 
1 
0.1 
0.9 
0.9 

Marine Fauna Impact 
Factor 
10 
1 
10 
10 

Marine Litter 
Impact 
10 
0.1 
9 
9 

Table 12 – Terrestrial Littering Impacts 

Material 

HDPE 
Paper 
PCL 
PLA 

Terrestrial 
degradation Factor 
1 
0.1 
0.5 
0.9 

Terrestrial Fauna 
Impact Factor 
2.5 
0.25 
2.5 
2.5 

Terrestrial Litter 
Impact 
2.5 
0.025 
1.25 
2.25 

Figure 12 - Overall Littering Impact 

Material 

HDPE 
Paper 
PCL 
PLA 

Terrestrial 
Litter Impact 
(T) 
2.5 
0.025 
1.25 
2.25 

Marine Litter 
Impact (M) 

10 
0.1 
9 
9 

Overall Littering 
Impact 
(O = T+M) 
12.5 
0.1 
10.3 
11.3 

Mass (g) 

1.96 
8.57 
3.10 
3.08 

Littering Impact 
Factor 
(O x mass) 
24.5 
1.1 
31.8 
34.6 

48 

 
 
 
 
11.0  Conclusions  

The goal of the study is to identify different possibilities to reduce the consumption of 
very lightweight plastic carrier bags by replacing them by other products that can be 
used for the same purpose. The study aimed to undertake a limited environmental 
footprint impact assessment of these possibilities.  

Based on the default scenario (which assumed a second use for PCL and PLA bags in 30% 
of cases), Table 13 shows the ranking of each material. The ranking has been developed 
based on the ‘robust’ EF categories previously shown in Figure 6. Performance has been 
ranked using a scoring from 1—4, denoting best to worst performance.   

In taking this approach it can be seen that:  

  Although HDPE is the preferred material for ozone depletion and particulate 

matter, it performs less well in climate change;  

  PCL performs worse than or equal to HDPE in all categories; 
  Although paper may be preferred from a climate change perspective it 

performs comparatively poorly in particulate matter; and, 
  PLA is neither the worst nor best performer in any category.  

The main conclusion that can be drawn from analysing the results in this way is that 
there is no specific material that outperforms the others in all categories. As such it is 
not possible to choose one over another. Moreover, the results also demonstrate that 
different types of compostable plastics vary in terms of the environmental impacts. To 
encourage the use of this material in general will not always lead to the best 
environmental outcome. This study focuses on two compostable plastics which perform 
notably differently; it may be the case that environmental performance of the myriad 
brands on the market may also be significantly variable. The different bio-based 
feedstocks and the differences in the proportion of petrochemical content will have a 
significant effect on this performance. As such, these results confirm that conclusions 
can only be drawn on the performance of individual products rather than the 
compostable plastics product group as a whole. 

Table 13 – Material Rankings Based on Robust EF Categories 

Material 

Climate change 

Ozone Depletion 

Particulate Matter 

HDPE 

PCL 

Paper 

PLA 

3 

3 

1 

2 

1 

4 

2 

2 

1 

2 

4 

2 

 
 
 
The two key assumptions that have the most impact are the mass of the plastic bags 
and the proportion that is given a second use as a compostable organic waste liner. 
The mass of plastic used in both the PLA and PCL bags is around 50% more than an HDPE 
bag which is due to the increased material density (a fairly static parameter) and the 
thickness of the film. This thickness may be decreased to improve the relative 
environmental performance, but potentially at the expense of product performance. The 
second use as a compostable organic waste liner, in particular, requires a sufficient 
thickness to carry the weight of the waste and to not degrade whilst in use so that the 
bag begins to split apart or fragments. 
Where levels of second use as organic household waste bin liner are relatively—and 
perhaps unrealistically— high (>80%), the compostable plastic bags have the potential to 
outperform HDPE in respect of climate change impacts but rarely in other EF categories. 
There also may be specific practical issues with taking such an approach for individual 
member states as organic household waste collection systems and their respective 
treatment processes can vary. 
When all 14 default EF categories are taken into account in assessing performance, 
HDPE is indicated to be the preferred material from an environmental point of view in 
all categories except for climate change. Data for this EF category is likely to be more 
robust than is the case for many of the others, notwithstanding issues that now arise 
from the need to properly account for the biogenic carbon emissions. Tackling climate 
change is also a priority for policy makers. This result therefore makes it difficult to 
confirm HDPE bags as the best environmental option overall. 
The results are also highly dependent on the sources of energy used within the 
secondary datasets for the different material processes. These are intended to be 
representative of the European situation. However, some outputs from the non-climate 
change categories suggest there may be a lack of consistency between the secondary 
datasets with respect to the age of the data, and the coverage of the inventory. Given 
the importance of energy assumptions, there may be scope for the best environmental 
option to differ between countries.  
With regards to the littering impacts, whilst these are of great importance when 
considering the environmental profile of the larger carrier bags, they are potentially less 
important for very lightweight plastic carrier bags due to the way in which they are used. 
Littering impacts are likely to be worse for all forms of plastic bag; the output from the 
biodegradation studies suggests that littering compostable plastic bags is likely to result 
in a similar environmental impact to HDPE bags. These bags are primarily designed for 
composting and therefore need a strict set off conditions (heat, moisture, bacteria) to 
degrade fully. Such conditions are unlikely to be present in the environment to which the 
bags are littered. This may lead the bags to persist in the environment thereby becoming 
a hazard to marine life if they are washed into seas and rivers. 

50 

 
 
 
 
APPENDICES 

 
 
A.1.0  Literature Review 

A.1.1  Studies from the UK 

A.1.1.1  UK Environment Agency (Intertek 2011) 

In 2011, the UK Environment Agency commissioned an LCA study52 from research consultancy 
Intertek based on the market situation in the UK in 2006. It was conducted to the ISO 14040 
standard and peer reviewed by an independent LCA expert and two packaging industry 
representatives. The study assessed the following types of carrier bag: 

  a conventional, lightweight carrier made from high-density polyethylene (HDPE); 
  a lightweight HDPE carrier with a prodegradant additive designed to break the down 

the plastic into smaller pieces (oxo-degradable); 

  a biodegradable carrier made from a starch-polyester (biopolymer) blend; and 
  a paper carrier. 

Three other more durable alternatives made from heavy gauge plastic or cotton were also 
assessed, although these are less relevant in the context of very lightweight plastic carrier bags 
as they are designed for multiple uses. The background data for the types of bags, the weights 
and their composition was taken from surveys of UK supermarkets. 

The functional unit was defined based on the capacity for each bag type to carry a months’ worth 
of groceries, i.e. how many bags would be needed each month to carry the given amount of 
groceries. From independent testing of a number of different bags made from HDPE, it was 
concluded that the limiting factor of the bag’s carrying capacity was the volume as opposed to 
the weight. Each bag was found to be capable of holding more weight than a person is 
reasonably expected to carry. Although this load testing was carried out specifically for HDPE 
bags, this assumption was also carried across the other material types, including paper bags. 
There is no justification or discussion provided as to whether any of the other materials would be 
weak enough for its weight carrying capacity to be the limiting factor rather than volume. This 
may be more of an issue for LW carrier bags than very lightweight plastic carrier bags. The latter 
would tend to be much smaller with limited scope to carry heavy items. 

Second use as organic household waste bin liner was considered in this study by subtracting the 
lifecycle environmental impacts of any ‘avoided products’. It was assumed that 40 per cent of the 
single use bags made from plastic would be used a second time as bin liners. This was calculated 
from a 2005 report53 for WRAP which found that 76 per cent of LW carrier bags were used a 
second time as organic household waste bin liner and of those 53 per cent were used as kitchen 
bin liners (53% x 76% = 40%). Paper bags were assumed not be suitable for this. 

52 Intertek Expert Services (2011) Life Cycle Assessment of Supermarket Carrier Bags: A Review of the Bags Available 
in 2006, Report for Environment Agency, February 2011 
53 Andrew Irving Associates Market Research (2005) Carrier bag usage and attitudes, Report for WRAP, March 2005 

52 

 
 
                                                      
 
From a transport perspective, industry data suggested all plastics bags were produced in Asian 
countries and the bio-based and paper bags were assumed to come from Europe.  

The results of the study, which are presented in Figure 13 for global warming potential (GWP), 
show that the HDPE bag has the lowest impact, followed by the oxo-degradable bag and the bio-
based bag. The paper bag has the largest impact of the single use bags due to its large material 
extraction footprint and the fact that no products were assumed to be avoided through second 
use.  

Figure 13 – GWP of Carrier Bag Life Cycle Stages 

Source: Environment Agency (2009) 

The marginal difference between the HDPE bag and the oxo-degradable bag is due to an 
assumption that the oxo-degradable bag weights slightly more. This is based on the average 
weight of the respective bags from UK retailers at the time rather than the functional properties 
of the bags. It is therefore unclear from this study whether there is any functional difference 
between the different types of bags, and subsequently a justification for assumptions relating to 
a weight difference between the two bag types. The LDPE and PP bags are reusable bags that are 
not relevant for very lightweight plastic carrier bags. 

Some sensitivities were investigated which examined different end of life scenarios. The baseline 
scenario, which provided the results in Figure 13, used the UK average from 2005. Based on this 
it was assumed that 86 per cent of the bags were landfilled and 14 per cent incinerated. 
Certainly, in the UK, this ratio has almost reversed, so these assumptions are less valid now. 

Recycling scenarios were also evaluated for all bags expect for the oxo-degradable bags. It was 
assumed that these are an undesirable element in recycling, although no specific evidence was 
presented that supported this statement. As seen in Table 14, recycling is the most preferable 
option for both the HDPE and paper bags, but in the case of HDPE, this is only true if around 40% 
of bags are used a second time as a bin liner. If paper is 100% recycled, it comes very close to the 
bio-based baseline value. However, if the bio-based bag is composted rather than sent to 

 
 
residual treatment its GWP is greatly reduced. It is worth noting that in many countries 
anaerobic digestion (AD) is used as the treatment method for source segregated organic 
materials. This can result in a better performance with respect to the GWP metric for some 
organic materials than is the case with composting, but such performance improvements are 
dependent on the extent to which the materials degrade under anaerobic conditions. Any 
performance improvement in this respect is, however, unlikely to be significant enough to be less 
than a conventional HDPE bag in the context of the Environment Agency study. 

Table 14 – End of Life Scenario Sensitivities 

Bag Material 

HDPE 

Bio-based 

Paper 

HDPE oxo-degradable 

Sensitivity 

Global warming potential 
(kg CO2 eq) 

Baseline 
60% Recycling, 40% second 
use as organic household 
waste bin liner 
100% Recycling 

Baseline 
60% Composting, 40% second 
use as organic household 
waste bin liner 
100% Composting 

Baseline 

100% Recycling 

100% Composting 

Baseline 

1.6 

1.4 

1.8 

4.2 

2.9 

3.3 

5.5 

4.4 

5 

1.8 

A.1.1.2 

Intertek 2012 (for Symphony Environmental) 

In 2012, Intertek also conducted a further LCA study54 on the three carrier bag products on 
behalf of Symphony Environmental—a UK manufacturer of the additive used in oxo-degradable 
plastic bags. This study is, in the literature review carried out for the current study, the only 
industry funded study without a peer review and its conclusions should therefore be viewed with 
caution. It was commissioned in response to the Environment Agency study (also conducted by 
Intertek) in order to “fully reflect the environmental benefits of oxo-biodegradable plastic”. 
The study looked at the following carrier bag materials; 

  Conventional HPDE; 

54 Intertek Expert Services (2012) A Life Cycle Assessment of Oxo-biodegradable, Compostable and Conventional 
Bags, Report for Symphony Environmental Ltd, May 2012, 
http://www.biodeg.org/New%20LCA%20by%20Intertek%20%20-
%20Final%20Report%2015.5.12%281%29%20%281%29.pdf 

54 

 
 
 
                                                      
 
  Oxo-degradable; and 
  Bio-based 

The functional unit was subtly different to the previous 2011 study in that it focused on; 

“The production, use and disposal of a single conventional light weight bag and 
alternatives of the same capacity” 

This is compared with the 2011 study, which used load carrying ability for a month’s worth of 
groceries. This means that the bags were not compared on a one for one basis if their load 
carrying capacity were different. The 2012 study takes a different approach because it did not 
have access to the industry data that allowed such a comparison. Instead, it created a scenario 
that allowed single bags to be fairly compared. Whilst both approaches are both valid, it is 
important to understand the difference and the potential impact on results. The former 
approach may be more accurate for specific country circumstances, but the latter allows the 
study to be applied to other locations and situations and the results are potentially easier to 
interpret. 

The overall conclusions of the study suggested that the bio-based bags produced around 50% 
more greenhouse gas (GHG) emissions during its life when compared with oxo-degradable and 
HDPE bags—both of which were reported to emit similar levels of GHG. Bio-based bags also were 
found to perform worse in the other ten environmental impact categories. Importantly, the bio-
based bags were assumed to weight 30% more than their equivalents although this assumption 
was not backed up with any specific data. 

There was also an attempt to quantify the environmental impact of littering although there is no 
standard or recognised way of achieving this currently. The methodology employed, focused on 
creating a proxy for how each of the materials degrade in the open environment on land—
omitting any reference to the impact of litter on the marine environment—by using data for 
sanitary landfill. In itself, this is problematic as the conditions found in landfill are very different 
to those found in the open environment. For example, most landfill degradation processes are 
anaerobic (without air), whilst plastic litter in the open environment will degrade aerobically 
(with air). The bio-based bags were also modelled using proxy data with a 50:50 mix of plastic 
and paper to attempt to take into account of the degradability of the bag. The justification for 
this is a LCA study by Murphy et al. which found that bio-based material would degrade by 30% 
in landfill. By assuming that the carbon content of bio-based plastic is 50%, this leaves 15% 
available to be emitted. Murphy is also quoted as stating that this is similar to paper at 12% and 
therefore is the proposed proxy. 

It was assumed that Oxo-degradable bags would not degrade as they need aerobic conditions 
that are not present in landfill. No scientific evidence was provided for this statement and 
although it is not strictly accurate, the result may be the same within an LCA as although there is 
a limited amount of aerobic degradation, this occurs immediately after deposition (before waste 
gets buried blocking off the air supply). Only biogenic CO2 is produced through aerobic 
degradation which is usually treated as carbon neutral in LCA. 

The ‘litter effects’ category attempted to quantify the social or ‘visual disamenity’ of littering. 
This is not a standard category in any recognised LCA methodologies and was developed 
specifically by Intertek for the purposes of that study. This was calculated by multiplying ‘the 
area of littered bags’ by the time taken to degrade. As the area of each bag was assumed to be 
the same, the degradation time is the defining factor.  

 
The degradation time for oxo-degradable plastic was assumed to be 91% over 24 months, based 
upon a study conducted in a simulated soil environment by Jakubowicz55 in 2011. The test, 
however, was conducted at ‘room temperature’ of 23oC (in line with the standard ISO 
17556:2012). It therefore appears to be inappropriate to assume that littered plastic will degrade 
at this rate as it is unlikely that the mean temperature will remain at 23oC for two years 
(especially within countries in northern Europe) and other conditions such as the levels and types 
of bacteria will differ. Indeed, it was found that high temperature composting actually reduced 
the degradation rate of oxo-degradable plastic which despite the higher temperatures was 
hypothesised to be due to the different types of microbial bacteria present.  

The degradation rate for bio-based and conventional HDPE bags was given as 50% and 0% 
respectively. The former figure is assumed to stem from the previous assumption that 50% of the 
bag will behave in a similar way as paper. The result of this is that litter effects (in m2/year) were 
calculated to be four times greater for conventional HDPE compared with both oxo-degradable 
and bio-based bags. 

The GHG emissions which contribute to the global warming potential of each bag throughout its 
life is shown in Figure 14 for the different disposal scenarios that the study investigated. For this 
particular environmental impact category it is clear that there are only marginal differences 
between the materials when production, transport and material impacts are taken into account. 
The compostable plastic bags become significantly worse when the disposal is taken into account 
for all methods of disposal apart from incineration. However, it is unclear within the study how 
biogenic carbon release during incineration is accounted for. One would expect bio-based 
material to perform significantly better in incineration than landfill as the carbon is released as 
biogenic CO2 rather than methane—methane being 22 times more destructive from a climate 
change perspective. Similarly, the GWP potential from the disposal assuming 100% litter (not to 
be confused with the ‘litter effects’ indicator) shows the bio-based bag producing even more 
CO2. Again, the approach to accounting for biogenic carbon is not discussed in the study, and 
although both the bio-based and oxo-degradable plastics are said to biodegrade when littered, 
the study reports a CO2 release of 88% and 15% respectively. No justification is provided around 
how these figures were calculated, yet they are significant factors in the GWP results for a 
littering scenario.  

55 Jakubowicz, I., Yarahmadi, N., and Arthurson, V. (2011) Kinetics of Abiotic and Biotic Degradability of Low-density 
Polyethylene Containing Prodegradant Additives and its Effect on the Growth of Microbial Communities, Polymer 
Degradation and Stability, Vol.96, No.5, pp.919–928 

56 

 
 
                                                      
 
Figure 14 – GWP of Carrier Bag Materials Using Different Disposal Scenarios

Source: Intertek (2012) 

Second use as a bin liner is briefly discussed by the study and excluded from the system 
boundary. The justification for this is that all bag types could perform a secondary use as a 
residual bin liner and therefore would all offset the use of an additional purpose bought liner. 
Whilst this a reasonable justification, there is no discussion on whether either of the alternatives 
to conventional HDPE would perform the same. For example, would some level of degradation—
and therefore reduction in structural integrity—occur during storage between uses? 

The key assumptions used in the study are summarised in the following: 

  Oxo-degradable plastic does not anaerobic degrade in landfill (the same as 

conventional plastics);  

  Bio-based bags anaerobically degrade in landfill and emit methane;  
  Bio-based and oxo-biodegradable bags aerobically biodegrade at different rates in the 

open environment; 
  Re-use is excluded; 
  Bio-based bags require a weight increase of 30% over HPDE bags to perform in a 

similar way; 

  All bags are produced in China and shipped to the UK; 
  The bio-based polymer used within the bio-based bag is produced in Italy and shipped 

to a bag producer in China; and 

  Bio-based and oxo-biodegradable bags aerobically biodegrade at different rates in the 

open environment.  

As seen in Figure 14 the transport assumptions are also potentially a key factor with regard to 
climate change impacts. The bio-based bag’s journey - from Italy, then on to China before 
travelling to the UK - appears account for a not insignificant amount of the overall impact and 
therefore it will be important to understand the supply chain for this (and other) alternatives.   

 
 
A.1.1.3  Defra (Imperial College London and NNFCC 2008) 

A life cycle assessment56 was funded by the UK’s Department for Environment, Food & Rural 
Affairs (DEFRA) in 2008 and commissioned by The National Non-Food Crops Centre (NNFCC) to 
explore the issues and to evaluate the environmental performance of biopolymer-based bags 
against conventional petrochemical carrier bags relevant to the UK. The study was undertaken by 
Imperial College London and peer reviewed by two internal and one external expert. The peer 
review appears to be fairly limited and was conducted on the final report without access to the 
primary data sources directly. 

The study focused on four grocery bag materials- 

  standard HDPE; 
  PLA blend named as ‘octopus’ bags (compostable); 
  Starch based Mater-Bi from Novamont (compostable); and 
  HDPE containing a pro-degradant additive. 

The first three are relevant to this study. The functional unit was to carry 10,000 litres of 
groceries at 75% of the bag capacity. This allowed bags of different size and volume to be 
compared. HDPE and PLA bags were found to have a similar carrying capacity to material weight 
ration whereas Mater-Bi could carry around 25% more.  

End of life disposal was also not split between different routes to reflect a real life case, but 
scenarios were built for each end of life process. The bags either went to 100% landfill, 
incineration, recycling (HDPE only) or composting (compostable bags only). This allows the best 
end of life scenario to be identified for each material, but may not reflect what does happen or is 
even possible currently. As this study was aimed at policy makers within the UK who may want to 
optimise waste management systems for a particular material this was appropriate for that 
study. This approach is not so appropriate for the current study which is aimed at the current 
situation and does not have the scope to suggest waste management changes to all Member 
States within the EU. 

Figure 15 shows the overall comparative results of the study for all disposal options. It uses an 
aggregated single environmental indictor score for each material. This approach to displaying 
results is generally used with caution as it introduces a great deal of uncertainty; it does, 
however provide a simple visual comparison. The best performing product is one made from 
HDPE with 90% recycling. In practice a combination of recycling and incineration is more likely, 
which would put it behind Mater-Bi, which has a similar impact for all disposal routes. The PLA 
(Octopus) product performs the worst unless its bag mass is brought in line with that of the 
Mater-Bi product. This suggests that bag mass relative to carrying capacity is a critically 
important assumption. 

Littering is discussed from a policy perspective, but not attempt is made to quantify the issue 
within the LCA study itself. 

56 Murph, D.R.J., Davis, D.G., and Payne, M. (2008) Life Cycle Assessment (LCA) of Biopolymers for single-use Carrier 
Bags, Report for NNFCC, September 2008 

58 

 
 
 
                                                      
 
Figure 15 - Comparison of the Environmental Impacts 

Associated with the Carrier Bags with all Waste Disposal Routes. 

A.1.2  Studies from the USA 

A.1.2.1  Boustead Consulting 

In 2007 Boustead Consulting57 was commissioned by the Progressive Bag Alliance—an American 
plastic bag advocacy group—to conduct a comparative LCA on three types of grocery bags: 

  standard HDPE; 
  compostable (PLA); and  
  paper  

The study was commissioned in order to argue against the banning of single use carrier bags, and 
its findings supported this view. The study was also independently peer reviewed. 

The functional unit was based on carrying capacity where it was assumed that paper bags had a 
larger carrying capacity than plastic bags. Table 15 shows some of functional attributes of the 
bags along with the resulting GHG emissions (the study also looked at energy and water use). 
The HDPE bag came out as the preferred option for GHG emissions although the bag gauge used 
may be considered too thin for general use and actually falls within the boundary of very 
lightweight plastic carrier bags (<15 microns). As such the data is particularly relevant to this 
study. A thicker gauge is used for the compostable bag, which is often the case in practice; 
however, the bag is also assumed to weigh around three times as much as the HDPE bag. With 

57 Boustead Consulting (2007) Life Cycle Assessment for Three Types of Grocery Bags - Recyclable Plastic; 
Compostable, Biodegradable Plastic; and Recycled, Recyclable Paper, Report for Progressive Bag Alliance, 2007 

 
 
                                                      
 
the density of PLA being around 1.25g/m3 and HDPE around 0.95g/m3 the bag should weigh 
closer to 11g (see other bag weights in Table 15). The HDPE bag would still be the preferred 
option used in respect of weight, but by not such a large margin.  

The GHG impacts of disposal are also assumed to be mostly from landfill; this also has a more 
favourable outcome for HDPE as it is inert in landfill. Incineration with energy recovery—which is 
more widely used since this study was conducted—would increase the disposal GHG of plastic, 
and possibly provide a benefit for PLA and paper as the CO2 emissions would be from biogenic58 
sources. The study also does not fully explore the consequences of any or all of the bags being 
sent to composting or AD. This may also have a significant influence over the results and is an 
important scenario to investigate further. 

Water use is also chosen as a key environmental indicator within the study. The results showed 
that the HDPE bag used far less water in its production than the alternatives. In a similar way to 
litter, however, there is also no standard methodology to calculate the impact of water 
consumption. Calculating the total water used is meaningless and quite often misleading if it is 
not presented in terms of the level of scarcity. This varies hugely between geographical areas 
and during different seasons. The same amount of water extraction can have varying impacts 
depending on where (and when) it occurs. 

Table 15 – Comparison of Bag Alternatives 

Compostable Plastic 
(PLA)  

Paper (30% recycled 
Fibre) 

HDPE 

5.78g 

Weight 

Gauge 

12.5 micron 

19 micron 

15.78g 

51.82g 

97g/m2 

Functional Unit 

1500 bags 

1500 bags 

1000 bags 

Production GHG 

Disposal GHG 

Total 

0.03 

0 

0.04 

0.15 

0.03 

0.18 

0.03 

0.05 

0.08 

Source: Derived from Boustead Consulting (2007) 

A.1.2.2  Clemson University 

A study from Clemson University59 was performed in 2014 with support from Novolex; a US 
based packaging manufacturer specialising in both plastic and paper bags. It was also 
independently peer reviewed by a team of three experts. The study looked at both HDPE and 
paper bags with varying amounts of recycled content, but the main focus of the study was to 

58 Biogenic CO2 emissions are defined as emissions from a source directly resulting from the combustion or 
decomposition of biologically-based materials rather than fossil fuels. 
59 Kimmel, R.M., Cooksey, K.D., and Littman, A. (2014) Life Cycle Assessment of Grocery Bags in Common Use in the 
United States, Report for Clemson University, 2014 

60 

 
 
 
                                                      
 
compare these bags against reusable bags; most of the conclusions of the study therefore relate 
to this. The functional unit was based on the number of bags used for one grocery shopping trip 
(containing 52 items) both with and without reuse after its initial use. Further sensitivities were 
also examined to ascertain how many reuses were necessary to offset the use of thicker gauge 
reusable bags. As with other studies the paper bags weigh more, but fewer are needed for each 
trip. The study used primary data collected by using 60 participants to pack actual products into 
the respective bags. The average number of bags used by the participants is shown in Table 16. 

Table 16 – Bag Attribute Comparison 

No. Bags per Trip 

Total wt. of Bags (g) 

HDPE 

9.8 

61 

Paper 

8.4 

457.2 

A number of environment indictors were used to assess the difference between the two bags 
types, and the results were broadly the same across all indictors with the exception of those for 
marine and freshwater Ecotoxicity, where the bag made from 100% recycled paper performed 
better. Figure 16 shows the results for GWP with second use taken into account. The study 
assumed that 40% of HDPE bags and 22.1% of paper bags have a second use as a bin liner. The 
former figure is based on actual data collected. As there was no data available for the latter, in 
this case the second use as organic household waste bin liner figure of 22.1% was derived by 
using the same ratio between HDPE bags not recycled (50.5% for paper and 91.4% for HDPE) and 
HDPE bags reused. Whilst just under half of the paper bags were assumed to be recycled at the 
end of life, much of the remainder was assumed to go to landfill—as was the situation in the US 
in 2011. Alternative disposal methods such as incineration may produce more favourable results 
for paper bags. However the study also showed that around 65% of the GHG emissions come 
from the raw material extraction and production processes, and therefore it is likely that the 
outcome would be the same in this case. End of life and transport emissions make up the 
remaining 23 and 12 per cent respectively. 

Figure 16 – Comparison of GWP between Paper and HDPE Bags  

 
 
 
 
 
The authors concluded that paper is the least desirable material for use in grocery bags unless 
reusable bags were discarded after a single use. Whilst littering is briefly discussed, no method 
for assessing the relative impacts of the different material was proposed in the study. 

A.1.3  Research from France 

In 2004, Ecobilan60 conducted a comparative LCA on behalf of French grocery chain, Carrefour. It 
was intended to be used to influence the chain’s policies around the use of carrier bags within its 
stores. It was also peer reviewed by the French Environment Agency (ADEME). The study was 
initially conducted in 2004 to include HDPE and paper bags, but extended in 2005 to included 
biodegradable (corn starch) bags. 

Similarly to other studies under review, Ecobilan used the functional unit of the requirement to 
carry a years’ worth of groceries. In this case it was based on in-store research which found that 
this amounted to 9,000 litres of purchases. Table 17 shows a comparison of the bags used in the 
study. Paper was found to need almost six times as much material to perform the same function 
as the HDPE bag whereas the biodegradable bag needed around 50% more. The results of the 
study were presented relative to HDPE to allow straight forward comparisons. In all of the 
environmental indicators the paper bag performed worse and in three of the indicators the 
biodegradable bag performed worse. In almost all cases, however, the difference in material 
usage is the defining factor— if the paper bag or the biodegradable bag used 50% less material in 
their construction to perform the same function, they would be comparable to the HDPE bag. 
This shows that the assumptions around the material content of the bag are of great significance 
to the end result. 

Table 17 – Comparison of Bag Alternatives 

HDPE 

Paper 

Biodegradable 

Weight (g) 

Usable Volume (l) 

Weight-Volume Ratio 

Consumption of non-
renewable energy sources  

Water Consumption  

GHG Emissions  

Atmospheric acidification  

6.04 

14 

0.43 

1 

1 

1 

1 

52 

20.5 

2.5 

1.5 

8.1 

2.5 

2 

17 

25 

0.68 

0.9 

1 

1.4 

1.6 

60 Ecobilan (2004) Évaluation des Impacts Environnementaux des Sacs de Caisse Carrefour, Report for Carrefour, 
2004 

62 

 
 
 
                                                      
 
Formation of photochemical 
oxidants  

Eutrophication  

Solid waste  

Littering Risk 

Source: Derived from Ecobilan (2004) 

1 

1 

1 

1.6 

19 

2.2 

0.4 

11 

1.1 

High 

Low 

Medium to Low 

A further indicator focused on littering risk was also presented. The study took the view that 
quantifying littering was troublesome and therefore used a number of parameters to provide a 
qualitative assessment of the likelihood of the bag being littered; 

  The number of bags handled at the end of life; 
  The probability of escape due to their weight—likelihood of being blown by wind; and 
  The persistence of bags in the environment. 

Both the paper and biodegradable bags were considered to have a lower littering risk than HDPE 
after this assessment.  

A.1.4  Studies from Australia 

A.1.4.1  Environment Australia, 2002 

In 2002, Environment Australia commissioned a study61 which looked into levies and financial 
incentives to reduce plastic bag use. As part of this they conducted a streamlined LCA by using 
secondary data to compare various alternatives; as such it was not peer reviewed for accuracy or 
methodological issues. Single use HDPE, paper and biodegradable bags were investigated along 
with examples of multiple use bags. Three environmental indictors were used to assess the bags: 
litter, GHG and energy use. The functional unit was based on the number of bags needed to carry 
a years’ worth of groceries. In the case of the three bag types of interest, this was deemed to be 
the same (520 bags) based upon an analysis of the bags available at the time. However, as shown 
in Table 18, the bags required differing amounts of material to achieve this. 

61 RMIT Centre for Design, and Eunomia Research and Consulting Ltd (2002) Plastic Shopping Bags – Analysis of 
Levies and Environmental Impacts, Report for Environment Australia, 2002 

 
 
 
 
 
                                                      
 
Table 18 – Environmental Impact Comparison for Bag Materials 

Weight (g) 

Litter (m2/y) 

GHG (kg CO2 
eq.) 

Energy Use 
(MJ) 

HDPE 

Paper 

Biodegradable 

6 

42.6 

12.5 

0.72 

0.08 

0.08 

6.1 

11.8 

6.6 

210 

721 

61 

Littering was taken into account by developing a specific metric for the study. It assumed that 
plastics would remain resident in the ‘litter stream’ for five years and paper and biodegradable 
polymers for six months. It is unclear what the term ‘litter stream’ means in the context of the 
study; however, it can be surmised that that authors expect that after these time scales the 
material would either degrade or be cleaned up. No evidence is offered in the study as to 
whether these timescales are realistic. It is also assumed that all the bags would be littered at the 
same rate of 0.5%; data to support this was taken from an Australian national litter studies for 
HDPE bags and no discussion is provided as to whether there would be differences between 
material types.  

The final litter indicator was calculated by taking 0.5% of the accumulated bag use per year 
(which was the same for all three single use material types), working out how much area this 
material would cover, and then applying the litter residency time factor. The litter results are 
shown in Table 18 along with GHG and energy use. For the litter category it is clear that the 
assumption for litter residency time is the defining factor as the HDPE litter impacts are around 
ten times that of the paper and biodegradable bags. 

GHG impacts are reported to be similar between HDPE and biodegradable bags, which is 
contrary to many of the other studies reviewed. The results are not broken down in enough 
detail (i.e. by life cycle stage) to ascertain why this may be the case especially as the 
biodegradable bag weight is over twice that of the HDPE bag. No in-depth discussion is provided 
in the report about the differences in materials, as the primary goal of the study was to compare 
single use with multi-use bags. 

A.1.5  RMIT Centre for Design, 2003/4 

A similar study62 was conducted in 2003 (and updated in 200463) involving one of the 
organisations (RMIT Centre for Design) that produced the 2002 report. On this occasion it was 
commissioned by Australia’s Department of Environment and Heritage, and it focused on the 

62 ExcelPlas Australia, Centre for Design at RMIT, and Nolan-ITU (2003) The Impacts of Degradable Plastic Bags in 
Australia, Report for Department of the Environment and Heritage (Australia), 2003 
63 James, K., and Grant, T. (2004) LCA of Degradable Plastic Bags, Report for Centre for Design at RMIT University, 
2004 

64 

 
 
 
 
                                                      
 
wider impacts and policy surrounding the use of biodegradable bags. Again, it was not a full peer 
reviewed LCA study but also attempted to build on the previous study. 

Six bag materials were chosen for their reported ability to biodegrade: 

  Polyesters 

o  Maize starch with polycaprolactone (Mater-Bi)  
o  Maize starch with polybutylene adipate terephthalate (Ecoflex)  
o  Maize starch with polybutylene succinate/adipate (Bionelle)  

  Starch-polyethylene blend 

o  Tapioca starch and high-density polyethylene (Earth-strength); 

  Oxo-degradable Polyethylene (TPA); and 
  Polylactic acid. 

Polylactic acid (PLA) is the only material in the study that is made entirely from renewable 
resources, the remainder are derived from varying combinations of hydrocarbons and plant 
based material. Paper and HDPE bags were also included as a sensitivity using the data from the 
2002 study for comparison. The functional unit was chosen as the carrying capacity of each bag. 
All were assumed to have the same carrying capacity although the PLA and Master-Bi bags 
weighed around 30% more.  

The end of life was modelled based on the Australian situation as shown in Figure 17. In the case 
of litter, four characteristics were used to calculate a litter impact:  

 
 
 

litter by area and aesthetics were deemed to be the same for all;  
litter by mass was higher for PLA and Mater-Bi as the bags weighed more; and 
the Earth-strength and oxo-degradable plastic were assumed to perform significantly 
worse than the other plastics with regards to marine biodiversity.  

This conclusion was generated as a result of an analysis of the available knowledge of 
biodegradability in the marine environment at the time. Importantly, it was also decided that all 
materials would be littered in the same amounts (0.5%) therefore it is assumed that the material 
type does not influence the behaviour of the user. 

Figure 17 – Waste Management Scenario 

 
 
 
 
Figure 18 – GHG Emission Comparison 

Source: ExcelPlas Australia, Centre for Design at RMIT, and Nolan-ITU (2003) 

Figure 18 shows the results in terms of GHG emissions for each bag material. Similar to other 
studies, paper was found to emit the most GHG during its life. In this case, methane is a 
significant contributor to this and can be attributed to degradation in landfill. Again, the high 
proportion of landfill disposal may not be appropriate for the current European situation. Both 
PLA and paper both emit so much more GHG than HDPE that it is unlikely a change in the end of 
life will result in a different conclusion, however. 

Figure 19 shows the impacts of the litter indicator which was developed for the study. This shows 
a reverse of the GHG impact as PLA and paper are the better performers in this aspect. There are 
issues with the approach however, as there was very limited information at the time that could 
allow a robust quantitative analysis of each material’s likelihood of biodegrading in the marine 
environment. This is especially true of oxo-degradable plastic. As with other approaches to 
quantifying litter impacts, the crucial factor is the time taken to biodegrade in the open 
environment and therefore how quickly the visual disamenity and risk to animals is reduced. 

66 

 
 
 
 
Figure 19 – Litter Impacts Comparison 

Source: ExcelPlas Australia, Centre for Design at RMIT, and Nolan-ITU (2003) 

 
 
 
 
 
 
 
 
 
 
 
 
 
A.2.0  General Assumptions and Calculations 

Table 19 – Average Bag Weight Calculation 

Upper  

Lower 

Material Density 
(g/cm3) 

Average Weight (g)1 

HDPE 

Paper 

PLA 

PCL 

Notes: 

12.5 μm 

8 μm  

37 gsm 

50 gsm 

15 μm 

15 μm 

10 μm 

10 μm 

0.97 

n/a 

1.25 

1.26 

1.  Calculated using the average thickness multiplied by the size 228 x 432mm (two sides) 

Table 20 – Plastic Bag Gauge Conversion Chart 

Gauge 
30 
40 
50 
60 
75 
80 
90 
100 
120 
150 
160 
180 
200 

Mil 
.30 
.40 
.50 
.60 
.75 
.80 
.90 
1.0 
1.2 
1.5 
1.6 
1.8 
2.0 

Micron 
7.6 
10 
12.5 
15 
19 
20 
23 
25 
30 
38 
40 
45 
50 

Millimetre 
.0076 
.0101 
.0127 
.0152 
.0190 
.0203 
.0228 
.0254 
.0304 
.0380 
.0406 
.0457 
.0508 

1.959 

8.569 

3.078 

3.103 

Inch 
.0003 
.0004 
.0005 
.0006 
.0007 
.0008 
.0009 
.0010 
.0012 
.0015 
.0016 
.0018 
.0020 

68 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
A.2.1  Datasets 

Table 21 – Raw Material/Manufacturing Datasets 

Material 

Process 

Dataset 

Database 

Data Quality/Scope Comments  Geography 

Year 

HDPE 

Raw 
material 

Bag 
production 

Polyethylene, high 
density, granulate {RER}| 
production 
Stretch blow moulding 
{RER}| production  

Ecoinvent 

Data derived from Plastics Europe Eco-profile. Aggregated 
data from 24 European production sites. 

Europe 

2010 

Ecoinvent 

Same process assumed for all plastic based bags 

Raw 
material 

Kraft paper, unbleached 
{RER}| production  

Ecoinvent 

No recycled content as recycling is accounted for at end of 
life. Data from one European producer. 

Ecoinvent 

Ecoinvent 

Ecoinvent 

Energy use only data on production of cardboard fluting 
(0.98 MJ/kg). Potential overestimation, however this is a 
small overall contribution.  
Starch based glue confirmed64 as basis of glue. Potato starch 
production used as proxy dataset. Glue proportion based on 
NNFCC report65 at 2.7% of paper use. 
Dataset from large Natureworks US based plant. Energy mix 
converted to European data. Data is plant specific data and 
aggregated therefore may not be representative of PLA 
process in EU.  

Europe 

Europe 

Europe 

Germany 

2007 

2007 

- 

- 

US/Europe 

2007 

Paper 

Bag 
production 

Electricity, high voltage 
{RER}| market group for  

Glue 

Potato starch {DE}| 
production  

Raw 
material 

Polylactide, granulate 
{GLO}| production 

Bag 
production 

Stretch blow moulding 
{RER}| production  

PLA 

PCL 

Ecoinvent 

Same process assumed for all plastic based bags 

Europe 

2007 

Raw 
material 

Polyester-complexed 
starch biopolymer {RER}| 
production 

Ecoinvent/Novamont 
EPD 2013 

Original data from 2004 Novamont EDP translated into 
Ecoinvent. Updated with 2010 EDP data to reflect increases 
in organic content (~30% - 60%) and agreed with Novamont.  
Highly aggregated dataset.  

Europe 

2010 

Bag 
production 

Stretch blow moulding 
{RER}| production 

Ecoinvent 

Same process assumed for all plastic based bags 

Europe 

2007 

64 Personal communication with Smith Anderson Group Ltd 
65 Murph, D.R.J., Davis, D.G., and Payne, M. (2008) Life Cycle Assessment (LCA) of Biopolymers for single-use Carrier Bags, Report for NNFCC, September 2008 

 
                                                      
 
Table 22 – End of Life Datasets 

Material 

Process 

Dataset  Database 

Data Quality/Scope Comments  Geography 

Year 

HDPE 

Paper 

Incineration 

Landfill 

Incineration 

Landfill 

Waste Paper 
Sorting 

Recycling 

Incineration 

PLA 

Landfill 

Waste incineration of plastics 
(PE, PP, PS, PB), EU-27 S 
Waste incineration of paper 
fraction in municipal solid 
waste (MSW), EU-27 S 
Waste incineration of paper 
fraction in municipal solid 
waste (MSW), EU-27 S 
Landfill of paper waste EU-27 
Waste paper, sorted {Europe 
without Switzerland}| 
treatment of waste paper.  
Waste newspaper {Europe 
without Switzerland}| paper 
production, newsprint, recycled 
Waste incineration of 
biodegradable waste fraction in 
municipal solid waste (MSW), 
EU-27 S 
Landfill of biodegradable waste 
EU-27 

ELCD 

ELCD 

ELCD 

ELCD 

Ecoinvent 

Ecoinvent 

ELCD 

ELCD 

AD/Compost 

Eunomia Atropos Model Data 

Eunomia 

All credits for the electricity and steam export are included. 
Uses European energy mix from 2002. 

Credits for generated energy product (electricity) from landfill 
gas utilisation are included 

All credits for the electricity and steam export are included. 
Uses European energy mix from 2002. 

All credits for the electricity and steam export are included 
Includes sorting of paper and transport to paper mill. Incudes 
small (0.25%) amount of waste, but overall losses are 
accounted for separately. 
Used as a proxy for the recycling of kraft paper. Uses the same 
recycling process (sulphate), but produces newspaper. Includes 
offset of virgin paper production. 

Paper used as proxy for the incineration of PLA 
All credits for the electricity and steam export are included. 
Uses European energy mix from 2002.  

Paper used as proxy for the landfill of PLA 
All credits for the electricity and steam export are included 
Modelled the degradation of paper in anaerobic digestion 
followed by composting process and offset of fertiliser by 
compost output 

Incineration 

Waste incineration of paper 
fraction in municipal solid 
waste (MSW), EU-27 S, 

Waste incineration of plastics 
(PE, PP, PS, PB), EU-27 S 

ELCD 

Proxy used based on split of bio/fossil carbon as 50% paper 
and 50% plastic 
All credits for the electricity and steam export are included. 
Uses European energy mix from 2002. 

Landfill 

Landfill of paper waste EU-27 

ELCD 

AD/Compost 

Eunomia Atropos Model Data 

Eunomia 

Paper used as proxy for the landfill of Mater-Bi 
All credits for the electricity and steam export are included 
Modelled the degradation of paper in anaerobic digestion 
followed by composting process and offset of fertiliser by 
compost output 

PCL 

70 

EU 27 

2006 

EU 27 

2006 

EU 27 

2006 

EU 27 

2006 

Europe 

2005 

Europe 

2000 

EU 27 

2006 

EU 27 

2006 

EU 27 

2006 

EU 27 

2006 

 
 
 
 
 
 
 
Table 23 – Transport Datasets 

Material 

Process 

Dataset  Database 

Data Quality/Scope Comments  Geography 

Year 

All 

ALL 

From 
manufacturer 
to 
supermarket 

End of life 
collection 

Articulated lorry transport, 
Euro 0, 1, 2, 3, 4 mix, 40 t 
total weight, 27 t max 
payload  
Municipal waste collection 
service by 21 metric ton lorry 
{RoW}| processing |  

ELCD 

Fuel Supply included. Vehicle production excluded 

Europe 

2005 

Ecoinvent 

Fuel Supply included. Vehicle production excluded 

Global 

2000 

 
 
 
 
 
 
 
A.2.2  Default Environmental Footprint Categories 

Table 24 – Default EF Impact Categories 

EF Impact 
Assessment Model 
Bern model -Global 
Warming Potentials 
(GWP) over a 100 
year time horizon. 
EDIP model based on 
the ODPs of the 
World Meteorological 
Organization (WMO) 
over an infinite time 
horizon.   

EF Impact Category 
Indicators 

Source 

Recommendation 
Level1 

kg CO2 equivalent  

Intergovernmental Panel 
on Climate Change, 2007   

kg CFC-11 equivalent 

WMO, 1999  

EF Impact 
Category 

Climate Change  

Ozone Depletion  

Ecotoxicity for 
aquatic fresh water  

Human Toxicity - 
cancer effects 

Human Toxicity – 
non-cancer effects  

Particulate 
Matter/Respiratory 
Inorganics  
Ionising Radiation – 
human health 
effects 
Photochemical 
Ozone Formation  

Acidification  

Eutrophication – 
terrestrial  

Eutrophication – 
aquatic  

Resource Depletion 
– water 

Resource Depletion 
– mineral, fossil 

USEtox model  

USEtox model  

USEtox model  

CTUe (Comparative 
Toxic Unit for 
ecosystems)   
CTUh (Comparative 
Toxic Unit for 
humans)   
CTUh (Comparative 
Toxic Unit for 
humans)   

Rosenbaum et al., 2008  

Rosenbaum et al., 2008  

Rosenbaum et al., 2008  

RiskPoll model 

kg PM2.5 equivalent   

Humbert, 2009  

Human Health effect 
model 

kg U235 equivalent 

Dreicer et al., 1995 

LOTOS-EUROS model   kg NMVOC equivalent  

Accumulated 
Exceedance model  
Accumulated 
Exceedance model  

EUTREND model  

Swiss Ecoscarcity 
model 

mol H+ eq  

mol N eq  

fresh water: kg P 
equivalent marine: kg 
N equivalent  
m3 water use related 
to local scarcity of 
water 

Van Zelm et al., 2008 as 
applied in ReCiPe  
Seppälä et al.,2006; 
Posch et al., 2008  
Seppälä et al.,2006; 
Posch et al., 2008  

Struijs et al., 2009 as 
implemented in ReCiPe  

Frischknecht et al., 2008 

CML2002 model 

kg antimony (Sb) 
equivalent 

van Oers et al., 2002 

I 

I 

II/III 

II/III 

II/III 

I 

II 

II  

II  

II  

II  

III 

II 

III 

Land Use 

Soil Organic Matter 
(SOM) model 

Kg (deficit) 

Milà i Canals et al., 2007 

1. 

Levels: “I” (recommended and satisfactory), level “II” (recommended but in need of some improvements) or level 
“III” (recommended, but to be applied with caution). 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
A.3.0  Results Breakdown by Material and Life 

Cycle Stage 

A.3.1  High Density Polyethylene (HDPE) 

Figure 20 shows the environmental impacts of each life cycle stage for HDPE. In the majority 
of the EF categories, the processing of the plastic granulate into bags is the dominant impact. 
The process uses electricity and so impacts are largely influenced by assumptions used for the 
electricity mix – coal generation is assumed for some countries. In practice this would reduce 
if the plastic granulate were to be produced in countries that have a less carbon intensive 
electricity grid—and increase in countries which have a greater reliance on coal. The disposal 
process has a net benefit for many of the EF categories although overall climate change is 
negatively impacted by the end of life stage. 

In contrast to the other bag manufacturing processes, which are more heavily reliant on more 
localised generation processes such as heat energy from district heating systems or wood 
energy, the energy used within the HDPE production process largely comes from electricity.  

Figure 21 shows the end of life process in detail which demonstrates that most of the negative 
carbon impact comes from incineration. HDPE bags release all of the embodied fossil carbon 
when it is burned; in contrast, the bags remain largely inert in landfill. The transition from 
landfill towards more incineration leads to one of the key differences in the results from this 
study when compared to previous comparative studies. This change makes HDPE perform 
worse during end of life stage due to the large increase in carbon emissions. In most of the 
other EF categories the increase in incineration leads to an improvement in performance, as a 
result of the offset of energy provided by the process. The generated electricity is fed back 
into the electricity grid and negates the need to generate the equivalent amount by other 
means. It is noted, however, that the HDPE end of life process is reliant on a secondary 
dataset that appears to use energy mix data from 2002 to calculate the offset energy. This is 
likely to overstate the benefits that may be attributed to energy from waste. 

73 

 
 
 
Figure 20 – HDPE Bag Life Cycle Stage Comparison 

Figure 21 – HDPE Bag- Contribution of End of Life Processes  

 
 
 
 
 
 
A.3.2  Paper 

Figure 22 shows the environmental impacts of each life cycle stage for paper. The dominant 
stage is the production of the kraft paper. The kraft paper process is a chemical based process 
(sulphate); the use and release of these chemicals accounts for a significant part of the 
environmental impact in a number of the toxicity and eutrophication categories. The negative 
value in the biogenic climate change category represents the uptake of CO2 from the 
atmosphere which is then sequestered into the paper during production. Much of this is then 
subsequently released during the end of life processes. 

Key impacts for paper include the following:  

  Particulate emissions – which are very high in comparison to the other types of 
bags - mostly arise from wood which is combusted on-site as the main source of 
energy used within the process;  

  Acidification – mostly arise from electricity generation; a relatively small impact 

arises from the use of sodium dithionite in the kraft process;  

  Ozone depletion is significantly influenced by the use of uranium in nuclear 

electricity generation as well as the use of heavy oil, which together account for 
half of the impacts; 

  Wood ash is assumed to impact on human toxicity; 
  Eutrophication is influenced by diesel burning and forestry harvesting. 

In some cases it is not clear as to why the impacts should be so much greater than is the case 
for the HDPE bags. Whilst the increase in particulate emissions is plausible given the heavy 
reliance on wood energy, it is not clear as to why acidification impacts should be so high given 
that these relate to electricity generation (the main source of energy also used in the HDPE 
process). Similarly, ozone depletion impacts are higher here than is the case for HDPE, and 
these also relate to electricity consumed within the process. 

A complete analysis of all related datasets incorporated into the secondary datasets was 
beyond the scope of this study. Such work would, however, need to be undertaken as part of 
a full PEF assessment. 

 Figure 23 shows the end of life process in detail. Both landfill and incineration are not 
considerable impacts due to most of the material (72%) going towards recycling. The recycling 
process, therefore contributes the largest amount to all categories. Negative impacts are seen 
in most categories as the recycling process is assumed to offset the need to produce paper 
from virgin fibres. This has a corresponding increase in biogenic CO2 as the offset paper will 
not absorb CO2 from the atmosphere. 

75 

 
 
 
Figure 22 - Paper Bag Life Cycle Stage Comparison 

Figure 23 - Paper Bag- Contribution of End of Life Processes 

A.3.3  Starch with Polycaprolactone (PCL) 

Figure 24 shows the environmental impacts of each life cycle stage for PCL. In this case the 
raw material manufacturing is the dominant process; this is in contrast to HDPE, where 
material processing is dominant. As they both use the same process for converting the 

 
 
 
 
 
 
feedstock material into an actual bag, this is an important observation. The main contributor 
to the EF categories is the production of maize as the feedstock for the plastic; this includes 
the pesticides and fertilisers used in the farming process. The avoided production of an 
organic household waste bin liner is also included, assuming in the central case a 30% rate of 
second use as bin liner for organic household waste, which reduces most of the EF categories 
by around 20%. 

The end of life processes have a relatively small impact for this material. Figure 25 shows each 
process in more detail. No individual process causes a greater negative impact, although the 
benefits gained from incineration energy export provide the largest benefit. 

Figure 24 – PCL Bag Life Cycle Stage Comparison 

77 

 
 
 
 
 
Figure 25 – PCL Bag Contribution of End of Life Processes 

Factors influencing the results for PCL include the following: 

  Particulate emissions are impacted by district heat which is used in maize drying, 
and in the production process, which uses a range of fuels including biomass and 
gas; the same processes also influence the acidification impacts; 

  Ozone depletion results are impacted by petroleum production used in naphtha, 
used to produce the synthetic element of plastic, as well as district heating in the 
production process which uses a range of fuels including gas 

  Terrestrial Eutrophication impacts are heavily impacted by agricultural processes 
relating to the growing and production of maize starch; this also affects marine 
eutrophication; 

  Human Toxicity impacts are also linked to the use of district heating energy. 

It can be seen that a number of the above points relate to impacts from the use of district 
heating system. As was the case with some of the paper impacts, it is not entirely clear why 
these impacts should be so much higher than the electricity generation impacts attributed to 
the HDPE process.  

A.3.4  Polylactic Acid (PLA) 

Figure 26 shows the environmental impacts of each life cycle stage for PLA.  

As with PCL bags, particulate emissions and acidification impacts are significantly impacted by 
the use of district heating in maize drying; district heating also influences the ozone depletion 
results. Eutrophication is similarly influenced by the grain production process, whilst district 
heating impacts on the toxicity results.   

 
 
 
 
Figure 26 - PLA Bag Life Cycle Stage Comparison 

Figure 27 – PLA Bag Contribution of End of Life Processes 

79 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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doi:10.2779/157729