Supporting our clients in navigating the tough methodological landscape behind LCAs of chemical recycling  

Recent support for a client to understand chemical recycling of PET

At RDC Environment, we supported a company in the beverage sector in evaluating the environmental performance of chemically recycled PET. The project focused on the life cycle assessment (LCA) of different chemical recycling plants for PET, providing the client with robust, science-based insights to inform strategic decision-making on the potential integration of chemically recycled PET into their bottles.

This article presents the general principles of PET chemical recycling as well as the key methodological considerations encountered when assessing such technologies through LCA, illustrating how rigorous environmental analysis can support innovation and circularity in packaging.

What is chemical recycling?

Chemical recycling refers to a set of technologies that convert plastic waste back into its chemical building blocks or other valuable intermediates, enabling the production of new materials with properties comparable to virgin plastics. For PET specifically, chemical recycling includes techniques such as:

• Dissolution: selectively dissolving PET to remove contaminants
• Depolymerization: breaking PET down into its monomers or oligomers
• Thermochemical routes like pyrolysis and gasification: these convert plastics into fuels or chemical feedstocks

Compared to mechanical recycling, which physically reprocesses plastics and is typically limited by polymer degradation and contamination, chemical recycling can handle more complex or lower-quality waste streams and offers the potential for closed-loop recycling into food-grade PET. However, it generally involves higher energy use and more complex processing, making careful environmental assessment essential when comparing it to established mechanical recycling routes.

Understanding Mass Balance and Chain-of-Custody for chemically recycled PET

In pyrolysis-based chemical recycling, recycled plastic is often processed together with other feedstocks in large-scale installations such as steam crackers, where materials are mixed and no longer physically traceable through to the final products.

This creates a key challenge in determining what share of recycled plastic ends up in specific polymers and how chemically recycled feedstocks can be credibly integrated into existing petrochemical value chains without misleading consumers. To address this, regulated chain-of-custody approaches are required to track recycled material flows and substantiate recycled-content claims. Mass balance, described in ISO 22095 which provides the general framework for Chain of Custody (CoC) models, is one such approach, with several implementation options including credit methods, rolling averages, polymer-only allocation, and fuel-use-exempt models.

In the European context, where energy recovery is not considered recycling, the allocation of credits to fuel fractions remains a key methodological discussion point. The European Commission has already adopted rules for calculating, verifying, and reporting recycled plastic content in single-use plastic beverage bottles under the Single-Use Plastics regulatory framework, primarily addressing mechanically recycled plastics. Additional guidance is still being developed to clarify how chemically recycled plastics, including pyrolysis-derived feedstocks, can be recognised in recycled-content targets, notably through mass-balance accounting approaches.

Recently published standards on Mass Balance and Book-and-Claim chain-of-custody models (ISO 22095-2 and ISO 22095-3) further clarify how these systems can be implemented and what types of claims can be made, supporting their consistent application in environmental assessments such as LCA and carbon footprint studies.

Are you thinking about integrating chemically recycled content into your product, and need support understanding the methodological implications? We can we support you in making informed decisions that advance circularity, sustainability, and regulatory compliance without compromising credibility.