A recent report by Peter Quicker from the University of Cologne discusses the status, potential, and risks of chemical recycling of plastic waste. The report was commissioned by the Swiss Federal Office for the Environment (FOEN) and published in May 2024. The author explains that chemical recycling is not yet a state-of-the-art technology, that its ability to deal with contaminated plastic waste is limited in practice, and that the environmental benefits of the process are often overestimated due to unrealistic assumptions.
Chemical recycling of plastics aims to convert plastic waste into monomers or other raw materials that are useful inputs for the chemical industry. The report shows that although a few (pilot) plants are in operation, chemical recycling still faces major challenges with highly contaminated plastic waste and with upscaling laboratory set-ups or pilot-scale facilities into economically viable operations (FPF reported). In addition, the claimed decontamination potential of contaminated waste has yet to be demonstrated in practice, in particular that the “contamination is not merely shifted to other products or residues” (FPF reported).
The potential environmental benefit of the technology depends on its ability to produce high-quality outputs while tolerating incoming mixed and contaminated plastic wastes that could otherwise only be incinerated or landfilled. The report reviews recent LCA studies of chemical recycling in detail and finds that many of the postulated environmental benefits are based on unrealistic assumptions. Many studies compare chemical recycling only to incineration (rather than also to other waste treatment options), make overly optimistic assumptions about the future performance of chemical recycling and what its outputs can replace (FPF reported), and fail to address by-products and residues. Plastic waste reduction, reuse, and mechanical recycling all generally outperform chemical recycling and should be preferred, according to the waste hierarchy (FPF reported).
Quicker also describes how chemical recycling economically depends on subsidies and massive corporate investment, to compete with fossil feedstocks. Misplaced financial support for chemical recycling could lead to industry lock-in into this technology and, as a result, a diversion of waste away from more environmentally beneficial waste treatment options. In countries with poor waste management, the operation of chemical recycling facilities may pose additional risks due to inadequate infrastructure or government oversight. Process risks can lead to environmental emissions or accidents, and rising exports of plastic waste to these countries can increase plastic pollution.
Overall, the report concludes that the technical feasibility, environmental benefits, and economic viability of chemical recycling are not sufficiently proven, which is consistent with previous reviews and reports (FPF reported, also here). According to the author, chemical recycling of plastics should not be excessively subsidized because of the risk of society being locked in to environmentally unfavorable processes and infrastructure. The report also states that a clear definition of chemical recycling, as well as clear rules to ensure recycled content is present in finished articles, are needed to avoid greenwashing (FPF reported, also here).
References
Quicker, P. (2024) «Status, potentials and risks of chemical recycling of waste plastics.» Swiss Federal Office for the Environment (FOEN). (pdf)
