03 Mar 2023

Written by

Lauriane Veillard, Chemical Recycling and Plastics-to-Fuels Policy Officer at Zero Waste Europe

‘Chemical recycling’ does NOT need flexible mass balance to scale up – here’s why

Chemical recycling

The European Commission is currently developing methods to calculate, verify and report recycled content in plastic bottles as part of the Single Use Plastics Directive (SUPD), and will continue this work for packaging. Indeed, the recently published Packaging, Packaging Waste Regulation (PPWR) proposal also includes recycled content targets. Once developed, the method will set a precedent and have further implications as  targets are being introduced for other types of materials and products – such as construction materials, batteries, vehicles and, most likely, textiles. 

Recycled content targets act as a lever to ensure recycled materials are used in the production of new materials and support the development of recycling techniques, thus fostering the shift towards a more circular economy. Yet, if the methodology is not well defined, these objectives will fall short. The chosen method should act as a safeguard, ensuring only high recycling yield technologies are promoted through recycled content targets.* 

Chemical ‘recycling’ covers a wide range of technologies producing different types of outputs, i.e. molecular feedstock, polymer, monomers, plastic compounding, etc. Losses occur in all recycling processes, so the longer the process to reach the final product stage, the lower amount of recycled content present in the final product. 

Promoters of some chemical ‘recycling’ technologies, namely pyrolysis and gasification, argue that the use of a flexible mass-balance approach is the only way to ensure the overall scale-up of chemical ‘recycling’ technologies.

Flexible mass-balance approach

Mass-balance is one of the different chains of custody models used to describe the link between a verified unit of production and the claim about the final product. The flexible approach allows for liberal allocation – meaning aggregating at the company level the overall amount of recycled feedstock to a specific part of the production, regardless of the actual proportion. In practice, this means, for example, that a producer can claim a bottle is made of “100% recycled content” when, in fact, that 100% is only a small proportion (10-30%, for instance) of the materials used to produce this bottle.

However, as not all chemical recycling technologies require the use of flexible mass-balance approach to achieve a high recycling yield, there is only one type of technology, namely pyrolysis and gasification, which are thermo-chemical technologies. There is an increasing number of chemical ‘recycling’ technologies able to use the batch-level mass balance, and still reach high level recycling yield – i.e. PET Depolymerisation, Pyrowave, glycolysis, etc. 

The use of flexible mass-balance approach is an unfair practice as it impacts the recycling yield of the technology. In the case of pyrolysis, the recycling rate would rise from around 10% up to 80% depending on the mass-balance approach used, while in reality no changes occur in the system. It destroys the level-playing field with other recycling technologies using less flexible mass balance – i.e. batch-level mass balance with proportional allocation, which doesn’t allow for playing with numbers to increase the recycling yield.

In order to have a methodology for assessing recycled content for plastic that acts as a safeguard by promoting first high recycling yield technologies, the same  conditions must be ensured for all players. Therefore, we are calling for a batch-level mass balance with a proportional allocation

This vision combines two aspects: 

  • Mixing occurring at the ‘production line’ – i.e. at the batch-level – to ensure that operationalisation of recycled content is mainstreamed across all sites; 
  • Ensuring proportional allocation to all output product to ensure claims reflect the actual proportion present in the product. 
*The recycling yield is the ratio proportion of recycled content coming from a technology compared with the input mass.

More information on this subject is available  in the following documents: