Fashion for Good launches recently the Mass Balance Demonstrator project, a collaborative industry initiative to implement and scale the mass balance attribution (MBA) chain-of-custody model for biomass-attributed PET in textile applications. The project represents a concrete step toward accelerating brand-driven decarbonisation across the apparel value chain.
While the portfolio of both preferred existing and next-generation materials offers opportunities for decarbonising the apparel industry, biosynthetics currently represent only a small fraction in material projections for 20301. The reality is that the dedicated commercial scale infrastructure required for biosynthetic materials is not yet fully developed, keeping production volumes prohibitively low and costs too high for widespread industry transition, despite their validated technical performance.
Borrowed from industries such as renewable energy and sustainable wood and paper, the mass balance attribution is a chain-of-custody model which allows renewable and fossil-based feedstocks to be physically mixed. It tracks how much renewable input entered the system and proportionally allocates that amount to the outputs, verified through audits and certification bodies.
How does Mass Balance Attribution (MBA) work
A chemical manufacturer introduces renewable feedstocks (such as agricultural residues or used cooking oil) into a production system that also processes fossil-based feedstocks. These feedstocks move through the same infrastructure and chemical processes, and by the time they become resin, they are chemically indistinguishable. The amount of renewable feedstock entering the system is carefully measured and recorded through a verified accounting system, creating a record of renewable input while accounting for process losses and conversion factors.
That accounted input is then allocated to specific products using mass balance principles. If 30% of the feedstock entering the system is renewable, a corresponding share of the output can carry a renewable attribution. In this project, this will be the biomass-attributed polyester (PET) but it could also be used for other fibres such as nylon. This does not necessarily mean each product physically contains renewable content; rather, the claim reflects the share of renewable input assigned to that product. Crucially, the system is strictly controlled: producers cannot allocate more renewable attribution than the amount of renewable feedstock entering the system, and once attributed, those certified attributes cannot be counted again elsewhere.
“We are at a point where the industry wants to move and adopt biosynthetics, but the production frameworks and commercial infrastructure haven’t caught up. The Mass Balance Demonstrator project is about closing that gap: building the impact and commercial evidence, the blueprint, and the feedback loops that will allow the MBA model to scale with integrity.” Katrin Ley, Managing Director at Fashion for Good.
The goals of the project
The Mass Balance Demonstrator project, an initiative led by Fashion for Good, brings together BESTSELLER, Beyond Yoga (Levi Strauss & Co.), ON, Paradise Textiles, Environmental Resources Management (ERM), Indorama Ventures, ISCC, UPM Biochemicals, and Textile Exchange. The consortium is designed not only to demonstrate what is possible today, but to generate insights that the wider industry can build on now and in the future.
“Polyester is our second biggest fiber by volume in BESTSELLER, which means we are continuously investigating improvements in this category. By taking part in this project we as a company are building experience within mass balance attribution and bio-attributed polyester. Hopefully, as we collaborate with other great partners, this can initiate pathways that can support scaling of renewable feedstocks (or inputs) going forward.” Anders Schorling Overgård, Material Research Lead at BESTSELLER
At its core, the project adopts and implements the mass balance attribution chain-of-custody model to enable the production of biomass-attributed PET for textile applications, demonstrating that existing manufacturing systems can integrate renewable feedstocks today. The project is structured around four interconnected objectives:
Producing biomass-attributed materials: the project will physically produce biomass-attributed resin and yarns, generating real-world output that matches performance parity.
Quantifying the climate impact: a comprehensive cradle-to-grave greenhouse gas (GHG) emissions model will be developed for the produced materials, delivering science-based insights into their decarbonisation potential and overall environmental footprint.
Developing a blueprint for industry scale-up: the project will deliver a practical roadmap for scaling biomass-attributed PET in the apparel sector, identifying key supply chain actors, assessing lifecycle accounting approaches for different chain-of-custody models, and evaluating the techno-economic feasibility of market deployment.
Informing climate frameworks and industry standards: insights from the project will be shared with climate initiatives and standard-setting bodies to help credible guidance on mass balance attribution.
