Waste-to-X: Quantifying the enviro-economic performance of chemical production via municipal solid waste gasification

Inadequate waste disposal methods currently employed around the globe are leading to substantial damage to both local human populations and the surrounding environment. Simultaneously, the chemical sector is facing pressure to shift from an unsustainable linear economy model and towards a more circular one. Municipal solid waste (MSW) gasification is a technology which is garnering increased attention as it offers a unified solution to both these issues. In this work, the economic and environmental performance of MSW gasification coupled with three chemical manufacturing routes (methanol, olefins via methanol-to-olefins, and ethanol) were compared to landfilling and incineration as a waste disposal method. Detailed process simulation is coupled with the monetisation of endpoint environmental impacts to determine the enviro-economic cost (EEC) of waste processing. Despite the high capital expenditure for all of the gasification routes, the break-even gate fees are competitive with both landfilling and incineration if the CO${}_2$ produced is recovered and sent to storage (CCS). However, if the CO${}_2$ is recycled and utilised (CCU), the break-even gate fees are significantly greater due to a higher green H${}_2$ demand. Both methanol and MTO routes offer significant reductions in environmental impacts due to offsetting fossil-based chemical manufacturing. All gasification routes have predicted EECs lower than both landfilling and incineration, with methanol coupled with CCS resulting in the lowest overall EEC at −£0.21/kg_MSW. Methanol production with CCU via MSW gasification is likely to be the most feasible option in the short term as it does not rely on the existence of CO${}_2$ pipeline infrastructure, but it would still need policy support via higher landfilling and carbon taxes. Overall, this work highlights the potential environmental benefit in coupling chemical manufacture with MSW gasification.