The transformation of plastics production from net positive greenhouse gas emissions to net negative: An environmental sustainability assessment of CO2-based polypropylene

Abstract

The production of plastics is heavily dependent upon fossil feedstocks, thus contributing to global warming. Power-to-X technologies provide new routes to chemicals and plastics production from captured CO 2 and renewable electricity. In this study, CO 2 -based polypropylene production via the methanol-to-olefins route is investigated. The main questions are twofold: 1) whether CO 2 -based polypropylene could be produced with negative net greenhouse gas emissions; and 2) if there is a risk that power-to-polypropylene production would lead to increased land use and water consumption. We performed a cradle-to-gate life cycle assessment with GaBi software to assess the global warming potential, land use and water consumption of CO 2 -based polypropylene. The net global warming potential of power-topolypropylene was found to be negative (-0.35 kgCO 2eq kg -1), meaning that more CO 2 from air is embedded in the polypropylene than is emitted during its production.Compared to fossil polypropylene production, power-to-polypropylene has little effect on water consumption but may lead to increased land use, especially through renewable power consumption. It seems that power-to- polypropylene production does have the potential to transform polypropylene production from being a carbon source to having a net negative global warming potential, which globally could play a significant role in climate change mitigation. A long-term carbon sink effect can be possible, if polypropylene is used in durable long-term applications, such as in infrastructure and construction, and its incineration and release of carbon can be avoided.