Life cycle assessment of alternative fuel production by co-pyrolysis of waste biomass and plastics

In the scope of energy transition and overall decarbonisation, various alternative fuels are investigated as potential substitutes for conventional fossil fuels. Co-pyrolysis has emerged as a potential solution for production of alternative fuels, while dealing with waste management issues, due to its ability to process different feedstocks. Biomass-derived fuels, with all their constraints, are already used on a commercial scale. Simultaneously, significant efforts are given to scale up fuel production from the thermal treatment of waste plastics. The fuel must be produced sustainably with minimal environmental impacts to be considered an alternative. This study presents the life cycle assessment (LCA) of waste biomass and plastic materials, co-pyrolysed with an aim to produce pyrolysis oil that could be used as a petroleum substitute. Moreover, the environmental impacts from the co-pyrolysis are compared to incineration and landfilling, which are today mostly used to deal with end-of-life plastics. The LCA is carried out in openLCA software using ReCiPe Midpoint 2016, and Environmental footprint methods. Results show that co-pyrolysis mostly reduces emissions associated with environmental impacts, even though this greatly depends on the treatment method used to divert the feedstock. Furthermore, most process emissions are associated with electricity consumption, therefore, integration of plastic processing with renewable energy sources can further reduce the environmental impacts. Finally, the products derived from the process should be of high quality with minimal after-treatment requirements to effectively substitute fossil fuels.