Comparative cradle-to-grave life cycle assessment of bio-based and petrochemical PET bottles

Iris Vural Gursel,Christian Moretti,Lorie Hamelin,Line Geest Jakobsen,Maria Magnea Steingrimsdottir,Martin Junginger,Linda Høibye,Li Shen

doi:10.1016/j.scitotenv.2021.148642

Abstract

This article presents a life cycle assessment of bio-based polyethylene terephthalate (PET) bottles with a cradle to grave scope and provides a comparison with petrochemical PET bottles for 13 environmental impact categories. Besides the baseline bio-based PET bottles, which are produced from Brazilian sugarcane reflecting status-quo, two alternative hypothetical bio-based product systems were considered: European wheat straw and European crops market mix composed of maize, wheat and sugar beet. The land-use change (LUC) impacts were assessed based on a deterministic model. The end-of-life impact was assessed using the EASETECH model. Baseline bio-based PET bottles performed overall worse than conventional petrochemical PET bottles, offering only better performance (about 10%) in abiotic depletion (fossil fuels). Comparable performance is observed for climate change (2% difference without the LUC, and 7% with LUC impacts). Using European crops for ethanol production (alternative 1) instead of Brazilian sugarcane resulted in a worse environmental performance, due to lower yields attained compared to Brazilian sugarcane. When wheat straw was considered as biomass feedstock for ethanol production (alternative 2), similar environmental performance with petrochemical PET bottles was seen.

Highlights

Given the societal concern about climate change and fossil resource consumption, bio-based plastics have emerged as a possible solution produced from renewable resources (Coppola et al, 2021)
polyethylene terephthalate (PET) is produced from monoethylene glycol (MEG), which accounts for approximately 30% by weight, and petrochemical purified terephthalic acid (PTA), which accounts for approximately 70% by weight
Looking at the dominance analysis of most recent PTA ecoprofile of PlasticsEurope (PlasticsEurope, 2016), p-xylene production and the related upstream processes is responsible for the majority of impacts (>60%) concerning these impact categories

Summary

Introduction

Given the societal concern about climate change and fossil resource consumption, bio-based plastics have emerged as a possible solution produced from renewable resources (Coppola et al, 2021) Though they currently occupy about a 1% share of the plastics market, worldwide bioplastics production has been forecast to increase (Skoczinski et al, 2021). This study aims to provide scientific evidence to support policymakers in their decisions about bio-based plastics (European Commission, 2018a; Giuntoli et al, 2019) by comparing, through LCA, the environmental performance of bio-based PET and petrochemical PET bottles. The Joint Research Centre of the European Commission is currently working on an LCA study on the potential environmental impacts of the use of alternative feedstocks (biomass, recycled plastics, CO2) for plastic articles in comparison to using current feedstocks (oil and gas) where beverage bottles are one of the case studies (Nessi et al, 2020)

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