Towards a circular PET economy: a comprehensive analysis of chemical recycling through Life Cycle Assessment (LCA) methodology

This study conducts a comprehensive Life Cycle Assessment (LCA) of chemical recycling for Polyethylene Terephthalate (PET), using the technology from a Swiss company as case study and PET bottles as reference product. The analysis examines the environmental impacts of this process across various scenarios, including the integration of renewable energy sources and biobased PET. An attributional LCA approach is applied, with 1 kg of PET as declared unit, covering the entire recycling process from waste collection to the production of recycled PET bottles. The switch to a nearly 100% renewable energy mix results in a 63% reduction in greenhouse gas emissions. The inclusion of partially biobased PET in the recycling system reduces the climate change impact by 19%, while fully biobased PET leads to increased impacts across most categories. The complementarity of chemical and mechanical recycling is also explored, highlighting the strengths and limitations of each within a circular economy context. Three future PET market scenarios are modelled, differing in the share of chemical recycling. Key findings show that while mechanical recycling offers superior environmental performance, its circularity is limited as it cannot process all PET waste types, necessitating more virgin PET production. Consequently, as the share of recycled PET decreases, the impact per recycled unit rises (i.e., when only mechanical recycling is used). Overall, the results indicate that combining chemical and mechanical recycling technologies, along with advancements in energy and material sourcing, is critical for enhancing both sustainability and circularity in PET waste management.