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Green Story's LCA methodology and robust approach to ensuring data accuracy

November 8, 2022
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The blog series by Dr Subramanian Senthilkannan Muthu, PhD in Environmental Life Cycle Assessment is divided into three parts. The second part details Green Story's LCA methodology and robust approach to ensuring data accuracy in the fashion industry.


The awareness of environmental footprints is omnipresent in business strategies but uncommon among consumer behaviors. With the vision of informed decision-making, Green Story is working to empower 1 billion people to know their impact and make choices that are better for the planet and the generations to come.
Green Story follows a rigorous methodology (discussed below in detail) to estimate the environmental footprints, which are later converted to equivalences that are easy to understand by the layman. To estimate the marginal savings or higher impacts, the brand’s supply chain is baselined with the material that has been
conventionally used to produce that product. This baselined supply chain is geographically consistent with the brand’s supply chains and considers all identical processes, with the raw material being
the only differentiator. It is to be noted that the impacts are not compared but baselined to the conventional supply chain in order to observe marginal improvements. In addition, Green Story has a mechanism for brands to offset the impacts generated by the product and indicates if a garment is carbon neutral or not.


 1 | Rigorous data collection

The fashion and textile sector has vertically integrated supply chains mainly characterized across the following stages.

  • Fibre production which leaves impact due to use of pesticides, fertilizers, use of agricultural land, and water consumption:
  • Spinning and fabric production which are energy- intensive processes;
  • Dyeing and finishing which uses toxic chemicals, discharge effluents, and intensive water & energy
  • Clothing or garment manufacturing phase which uses energy and usually has comparatively lesser impacts.

Transportation of raw materials and finished goods has a significant share as the apparel industry is a global enterprise and depends on fossil fuel-based traction. Fibre production has considerable impacts and is the most critical one whereas the other processes/stages are also dependent on the type of material based on its origin i.e. plant, animal or crude oil based. The data collection procedure is divided based on three types of LCA studies undertaken by Green Story

  • Screening LCAs: These studies are based on the secondary datasets and LCA data are collected for the location of all the suppliers to use the geography-specific secondary datasets, energy (electricity and thermal) sources with valid proofs at each facility, and water treatment technology with certificates for each facility. In addition, information on the technology front, such as type of knitting, printing, etc. is also gathered to use the apt datasets.
  •  Comprehensive LCAs: In addition to the information asked for screening LCAs, the detailed data questionnaires are developed for all energy, and non-energy resources (raw materials, chemicals, water), followed by the emissions data. Questionnaires cover each phase of the life cycle in detail. All the data are further benchmarked with industry standards, and mass balance is ensured. Green Story also performs field visits for on-site validations.
  • Hybrid/ Customized LCAs: These studies are hybrid in a way where primary data are only used for a few life cycle stages like fibre production, and further complemented by secondary datasets for the stages the primary data are not feasible from the client’s side.

However, Green Story recommends conducting a comprehensive primary data-based LCA study to all brands.

2 | Usage of validated datasets

The best way to estimate the environmental impacts using LCA is to use primary data for all the life cycle stages involved in the specific supply chain, as the secondary datasets represent the average operations of multiple farmers or manufacturers. However, this involves a higher cost, more time, and increased effort, which refrains most of the brands to go for such studies. Lack of awareness also remains the key factor. Whereas legislation supporting more studies backed by third-party reviews can encourage brands to conduct such studies with incentives for better performance and penalties for worse.

With such constraints, Green Story ensures to use most representative secondary datasets based on consistent geography as of the supply chains analyzed. The representative technology-specific dataset is used and robustness can be assumed based on the example of the different datasets used for the dyeing process, i.e. the different datasets for disperse dyeing processes are used for light, medium, and dark disperse dyeing.

However, there are constraints in the availability of secondary datasets as well, for which the available datasets from similar geography (such as using developed/developing country datasets are adapted to supply chains which are analysed. This is to make sure that all the energy sources of the analyzed geography are used which is the key contributing factor to impacts. Apart from using the external, scientific databases and the data from peer-reviewed literature, Green Story has its own credible, scientific database, which is also used to model supply chains. All the sources of datasets are mentioned transparently in the final LCA


Baselining methodology

Green Story avoids comparative assertions for LCA study without any third-party review, following requirements of ISO 14044 standard (Section 4.3). Product Category Rules and PEF (PEFCRs) also provide a strong and clear structure to guide the comparative LCA study. Similarly, the ILCD has prescriptive requirements for comparative studies to ensure equivalence between product systems being compared.

Green Story has developed a methodology to look at marginal savings or impacts from the specific supply chain. The brand’s supply chain is baselined with an identical supply chain that is geographically consistent. For example, if the difference in the supply chain lies in the fibre production stage and the subsequent downstream processes are identical, then the baselined fibre is selected based on the functionality of the product and the origin of the material, i.e. cotton will not be baselined by polyester or nylon.

Valid proofs for renewable energy/ water recycling/biodegradable material.

Energy consumption and production is directly related to environmental impacts, including climate change, air pollution, water pollution, etc,. based on the source of fuel used. This can also lead to energy greenwashing when a supplier claims to be using green, or, 100% renewable, but in reality, it is consuming
“dirty” energy. Essentially, making fossil fuel electricity seems clean.

At Green Story, renewable energy is only modeled on acceptance of valid renewable energy proof, failing to which regional grid mix is used to model electricity supply. Similarly, the water treatment methods, recycling of water, credits for recycling, biodegradability of materials, or any other sustainability practices are only considered on acceptance of valid proofs.

Review mechanism

Green Story assures quality of the LCA’s undertaken by review at each stage with the strong review team for LCA modeling and for the LCA reports conforming to ISO 14040/44. The review comments and the way they are addressed are documented for each project. The peer-review team at Green Story makes sure that these
reviews are not second to critical reviews as per the requirements of ISO 14044.

The studies which are meant for public disclosures undergo a third-party critical review, however, for the studies which are meant for internal purposes, Green Story conducts an internal peer review to assure the credibility of such studies as well.

To Be Continued

Stay tuned for next week as Dr. Muthu talks in detail about the differentiation between Green Story and HIGG MSI.

Register for Green Story’s Webinar

Join our Chief Sustainability Officer Dr Subramanian Senthilkannan Muthu, PhD and Katina Boutis, Director of Sustainability at Everlane on Wednesday November 9th 2022 at 4pm (CET) as they discuss the use and misuse of data in fashion’s sustainability claims and the role LCA plays in measuring the environmental impact of fashion. Register here

About Dr. Subramanian Senthilkannan (Kannan) Muthu, Ph.D.

Dr. Kannan Muthu is the Chief Sustainability Officer at Green Story and widely regarded as the foremost expert in textile Life Cycle Assessment (LCA) in the world.

Prior to Green Story, he led the Environmental Services Division-Asia of SGS and was head of Sustainability of SgT Group. With a PhD in Environmental Life Cycle Assessment in Textiles and Clothing, Dr. Muthu is a Textile Technologist and has published 140 scientific books and 100 research articles. He has over 12 years of experience in environmental and chemical sustainability and has worked with hundreds of factories and international leading brands’ supply chains. His body of work makes him one of the most respected and widely quoted figures in the field of LCA.