The global warming potential and the material utility of PET and bio-based PEF bottles over multiple recycling trips

Biomass use and recycling are among the few options to reduce the greenhouse gas (GHG) emissions of the growing plastics sector. The bio-based plastic polyethylene furanoate (PEF) is a promising alternative to polyethylene terephthalate (PET), in particular for small bottle applications. For the first time, we assessed the life cycle global warming potential (GWP) for 250 mL PET and PEF bottles over multiple mechanical (MR) and chemical (CR) recycling trips in the Netherlands. We found that bio-based PEF would offer 50–74% lower life cycle GHG emission after one recycling trip compared to PET, depending on the waste management case. Our results also show that deposit-based recycling systems significantly reduce the cumulative cradle-to-grave net GHG emissions for both bottle types, especially when multiple recycling trips are applied. We propose complementary material utility (MU) indicators to reveal synergies and trade-offs between circularity and GWP: While deposit-based CR shows the best performance in terms of MU, it falls behind deposit-based MR when it comes to net GHG emissions due to the energy intensity of CR. Hence, combining mechanical and chemical recycling could contribute to achieving the goals of the circular economy and climate change mitigation alike.