Comparing life cycle energy and GHG emissions of bio-based PET, recycled PET, PLA and man-made cellulosics

Abstract

The purpose of this paper is to review the environmental profiles of petrochemical PET, (partially) bio-based PET, recycled PET, and recycled (partially) bio-based PET, and compare them with other bio-based materials, namely PLA (polylactic acid, a bio-based polyester) and man-made cellulose fibers (cellulose fiber produced from wood pulp, i.e. Viscose, Modal and Tencel). Life cycle assessment (LCA) studies on polymers, fibers and bottles made from these materials are reviewed. Only non-renewable energy use and greenhouse gas (GHG) emissions are considered. The scope is cradle to grave excluding the use phase. The results show that both recycled and bio-based ma terials offer important environmental benefits over single-use petrochemical PET. Among the four PET product systems studied, recycled (partially) bio-based PET has the lowest impacts, followed by recycled PET, (partially) biobased PET, and petrochemical PET. PLA and man-made cellulose fibers produced in an integrated plant have lower impacts than both petrochemical PET and bio-based PET. The impacts of recycled products are strongly influenced by the choice of the allocation method applied to open-loop recycling.