What do LCAs help us understand about chemical recycling?

Life Cycle Assessments (LCAs) are a widely used tool that utilizes comprehensive, transparent, and science-based approaches to help evaluate potential environmental impacts of goods and services. LCAs have recently been used to evaluate chemical recycling technologies, including pyrolysis, depolymerization, and dissolution.

Understanding LCA results requires context.  When conducting LCAs – and when evaluating their results – it is important to transparently set forth the goal, scope, system boundary, functional unit, and allocation approaches regarding choices and assumptions used in modeling to ensure reliable results and to support consistent comparisons.  It is also important to understand any inherent limitations and uncertainties, as they can influence results and their interpretation.

An example of the importance of context is in the evaluation of “avoided emissions” from chemical recycling. In these cases, the phrase “avoided emissions” refers to greenhouse gas reductions that occur when these processes displace more carbon-intensive alternatives, such as virgin plastic production, landfill disposal, or incineration. Including avoided emissions, or other avoided impacts, can add valuable context and insights to an LCA in understanding the net environmental benefits of chemical recycling. However, any avoided impacts must be applied transparently, with clearly defined assumptions, methodological rigor, and well-established baseline scenarios and system boundaries to avoid miscommunication. Full-system comparisons are essential to prevent misleading conclusions, as key factors such as conversion rates, energy and process efficiency, end market substitutions, and regulatory and market dynamics can influence overall calculated avoided emissions.  

While they can help inform decision-making, LCAs are generally not suitable as the sole determinant for financial decisions, policymaking, or substantiating sustainability.