Lost in the shuffle
Mass balance models, common in fair trade goods, are used when physical traceability is deemed unfeasible. Its innate lack of transparency raises real questions: does it muddy the water and is it, therefore, a form of greenwashing? Or can it encourage the petrochemical industry to lessen its dependence on fossil fuels?
Mass balance is presented as a pathway to more responsible products. A common practice in fair trade and petrochemical commodities, its workings are not complicated to understand, but its benefits are.
At consumer level, it offers no guarantees of the actual presence of recycled or fair trade farmed fibres in a product, and the concept will not be described on any eco-label. Proponents of this model often cite green energy as a virtuous example. When available, solar or wind power is fed into the grid. When solar and wind are lacking, conventional non-renewable resources supply the electricity. This system may encourage a smooth transition to cleaner energy, but there is no way to know, when you flick a switch, what type of energy powers the lighting.
The model is useful for products that are indiscriminately mixed at an early stage of a supply chain. This includes cotton. Better Cotton and Aid by Trade, for its Cotton made in Africa label, use mass balance to attribute responsible practices to the farmers. Both organisations, however, have sensed a change in market acceptance and are introducing systems based on physical tracers to offer stronger guarantees of provenance. Conversely, chemicals companies successfully convinced Textile Exchange to modify the scope of its Global Recycled Standard (GRS) and Recycled Content Standard (RCS) to allow for advanced chemical recycling and mass balancing in 2024.
“The chemical industry is undergoing a raw material transformation. While a major part of chemical production is still based on fossil raw materials, BASF is taking steps to become less dependent on fossil resources,” says Birgit Hellmann, BASF’s communication manager for chemical recycling. The German chemicals company’s aim, she adds, “is to use more renewable and recycled raw materials in existing production plants”. This is the crux of the issue: alternative feedstocks can be fed into conventional fossil fuel processing infrastructures. Mass balancing allows incremental progress without the expense of building new facilities dedicated entirely to plastic waste or biomass.
Eastman’s sustainability leader for textiles, Claudia de Witte, shares this view. She says: “At our headquarters in Kingsport, Tennessee, we operate a large, integrated cellulose facility that is over 100 years old and that has been designed to operate on virgin feedstocks. To produce Naia Renew, sourced from certified recycled content, we are using existing, at-scale infrastructure, using mass balance to identify and capture the benefits of certified recycled content.”
The polyester renewal technology, based in Kingsport, has been running and generating revenue since March 2024 and now Eastman plans to build two additional recycling facilities using the same technology, one in Texas and one in France. Each of the plants will have the capacity to process more than 100,000 tonnes of hard-to-recycle, polyester-rich waste per year.
Incremental progress
The advantage of the system is that customers have access to ‘greener’ chemicals that are absolutely identical to virgin ones. “These alternative raw materials are fed into the production chain, alongside fossil raw materials, at such an early stage that the end products remain chemically unchanged,” says Ms Hellmann. BASF applies the mass balance model to a gasification process that is fed with biomass waste, which it calls Biomass Balance. And for products from its ChemCycling line, which processes a combination of fossil raw materials, it feeds in plastic waste and end-of-life tyres. It calls these Ccycled products.
Among the hundreds of chemicals that BASF produces, caprolactam, used to make polyamide, can now carry a recycled or bio-based label as a result of mass balancing. “The corresponding share of recycled feedstock, for example pyrolysis oil, is attributed to the specific Ccycled product via a certified mass balance approach,” she says, while admitting that “the recycled feedstock is not measurable in the BASF mass balance product.” BASF facilities and Ccycled products are certified by REDcert2 and ISCC Plus. These two certification schemes, it should be noted, are industry-led initiatives.
Distinct processes
Two distinct processes are at work at Eastman. Its Carbon Renewal Technology (CRT) uses a wide range of hard-to-recycle waste material, which is broken down to the molecular building blocks to produce a high-quality syngas that the company uses as feedstock for its cellulose acetate production process. This is in use in its production of Naia Renew staple fibres and filament yarn, which are sourced from 60% sustainable sourced wood pulp and 40% GRS-certified recycled waste materials.
In parallel, its Polyester Renewal Technology (PRT) uses a methanolysis process to break down hard-to-recycle polyester waste into the basic monomers. It uses these monomers to create virgin-like co-polyesters with the same properties as legacy counterparts.
Both technologies ensure an end-of-life solution for waste that would have been otherwise landfilled, incinerated or lost in the environment. They also contribute to reducing reliance on fossil resources and enable production with a lower carbon footprint. Both are examples of what Claudia de Witte calls “material-to-material recycling”.
Eastman applies an allocation system known as credit-based mass balance, creating credits linked to the recycled feedstock mass. These are decoupled during processing, and recoupled after recycling, Ms de Witte explains. “It is based on actual yields and usage into material production,” she adds. “Everything is checked, third-party verified and includes virtual and physical traceability.”
Increasing recycled nylon availability
In the activewear sector, recycled polyamide is the main fibre that owes its “recycled” label to mass balancing. The limited volumes of production waste and of pure polyamide post-consumer waste make this low-impact solution quite useful for nylon producers when brands request materials with recycled content. Fulgar, in Italy, uses BASF’s Ccycled polymer in its Q-Cycle yarns. BASF also supplies adipic acid, made from its Biomass Balance process, to Nilit for its ByNature nylon yarns.
“This solution is easy to implement into any collection and contributes to an end goal of reducing carbon emissions,” points out Michelle Lea, marketing manager for Nilit. The Sensil ByNature yarns are also ISCC Plus certified. “As you cannot trace the biogas to the final yarn, this certification provides a way for brands to show that they are having a positive impact by using these yarns. If they want to claim the garment reduces CO2 emissions, then the brand also needs to be ISCC Plus certified,” she notes.
BASF has, like Eastman, worked with Textile Exchange to adapt the organisation’s recycled standard to accept mass balancing. Under Textile Exchange’s new “alternative volume reconciliation” platform, BASF obtained Recycled Claim Standard (RCS) certification for its Ultramid Ccycled polyamide 6 and 6.6 in 2024.
Other nylon producers apply mass balance principles. Ascend, in the US, feeds its Bioserve platform with a portion of used cooking oils allocated to an ISCC Plus-certified nylon 6.6. In Spain, Nurel also sources ISCC-certified caprolactam, made from pre- and post-consumer residues or biomass. “We buy ISCC certified caprolactam and feed it into our production plant. In the end, we attribute 100% of certified caprolactam to our polyamide 6,” Silvia Catalán, Nurel’s sustainability manager, said in an ISCC press release.
Making claims
Better Cotton, a Swiss non-profit, has mass balanced cotton produced according to its guidelines since its inception in 2009. “It is the chain-of-custody model that laid the foundation for Better Cotton, helping scale our programme and bring immense value to farming communities,” says a company spokesperson. When a brand or retailer becomes a member of the organisation, it can then “make ‘claims’ about commitments made to Better Cotton, and the impact of those commitments”. But the organisation is phasing out the Mass Balance Chain of Custody and introducing a new certified standard backed by a physical tracer. The Better Cotton label will now only be allowed on products made from cotton sourced through this new traceability programme.
At the Aid by Trade Foundation (AbTF), based in Hamburg, a similar move is in the works with the launch of a new Transparency Standard. Prior to this, a company spokesperson says, two systems were used for Cotton made in Africa: Hard Identity Preserved, which tracks cotton from bale to finished product, and Mass Balance “for balancing CmiA cotton with other cotton origins at spinning mill level”. The new traceability platform comes atop these two streams, offering a higher level of assurance and a digital passport.
Courting controversy
These two organisations are addressing one of the main issues that mass balance critics cite: despite what is written on a label, it is impossible to guarantee that ‘better’ cotton is present in any given T-shirt or trousers. It is misleading to consumers. The principle also has critics in the recycling sector. If there is no way to prove that recycled chemicals are present in the final product, it does a disservice to other forms of recycling. Mass balancing is also accused of allowing chemicals companies to pursue business as usual instead of setting up production lines dedicated solely to recycling waste.
Allocation allows a company to make 1% of recycled input appear to be 100% recycled output, says Josse Kunst, general manager of Dutch company CuRe, the developer of a PET plastics and polyester recycling technology. “With mass balance, a product that has not a single recycled molecule in it gets credit at consumer level for having recycled content. This is why I call it ‘Enron’ recycling,” he says, adding that it also diverts funds needed for the development of truly ground-breaking recycling technologies.
“There are recycling processes for packaging and textiles that are not mass balanced, but have a physical one-to-one ratio,” says Ashley Holding, sustainability consultant at Circuvate. “I understand the chemical industry’s position, as it is not viable to build a plant dedicated solely to recycled feedstock. It’s much easier to mix waste with virgin input. But I also understand the frustration from the consumer’s side.” One solution he sees would be to have better certification, but he says even lifecycle assessment (LCA) has no clear position on mass balance.
Zero Waste Europe questions the very notion of associating recycling with pyrolysis. “These chemicals are not recycled but rather recovered,” says Lauriane Veillard, policy officer at ZWE, a network of advocacy groups working to reduce and prevent waste. UK Without Incineration Network (UKWIN) is its member in the UK. “It is not fair to put mechanically recycled plastics and pyrolysis on the same level,” she continues. “In any given pyrolysis plant, less than 2% of the output is being used to make ‘recycled’ plastics.”
The organisation’s 2023 Leaky Loop report exposed the many inefficiencies of pyrolysis. But the problem with mass balance is the allocation system that diverts ‘green’ claims to high-value output chemicals. For ZWE, inputs need to be shared across all product streams. Ms Veillard notes that in the US, the Environmental Protection Agency (EPA) has been pushing for allocation by weight.
For those on the fence, mass balance is a necessary stage in the petrochemical industry’s transition to renewable resources. But everyone agrees that the system is opaque. “What we need is transparency. A product should clearly display its recycled content, whether it is one, five, ten or even 100%,” says Mr Kunst, who believes that 100% recycled is too good to be true. “Mass balance could be used in a one-for-one system. It could be made simple, clear and easily understandable, not a smokescreen.”
While the smokescreen is being phased out by fair trade and responsible cotton organisations, in synthetics it appears to be spreading. Mass balance may be a pragmatic solution for the petrochemical industry, and for synthetic-dependent perform- ance clothing brands. It is not however a realistic one, as the so-called low-impact chemicals are lost in the shuffle.
The recycled biomass-balance adipic acid that Nilit uses to make its Sensil By Nature yarns is produced by BASF, and uses harvested methane as a biogas to replace some of the fossil fuels that would otherwise be used to make the raw material.
CREDIT: Nilit
