Economic and life cycle assessment of novel hybrid energy and fuel generation systems from municipal waste through plasma gasification and anaerobic digestion coupled with carbon capture and storage

Abstract

Achieving climate goals demands novel system designs that enable the conversion of municipal waste, such as plastic and food waste into energy and fuels with minimal environmental impact. This study proposes an innovative multi-energy generation system that integrates plasma gasification for plastic waste and anaerobic digestion for food waste, coupled with carbon capture and storage (CCS) technologies. This novel conceptual design aims to maximize energy recovery while reducing lifecycle emissions compared to conventional waste-to-energy (WtE) pathways. Two novel system configurations were assessed: (1) a combined cooling, heating, and power (CCHP) system, and (2) a CCHP system integrated with liquid biomethane production. Each configuration was evaluated under three CCS strategies: no CCS, pre-combustion CCS, and post-combustion CCS. The economic analysis and life cycle assessment (LCA) highlight the economic and environmental trade-offs of each design. Specifically, in Scenario 1, the levelized cost of electricity (LCOE) increases from 0.171 USD/kWh (no CCS) to 0.311 and 0.354 USD/kWh while in Scenario 2, the levelized cost of biomethane (LCObM) rises from 0.176 USD/kWh to 0.314 and 0.374 USD/kWh for pre- and post-combustion CCS, respectively. While CCS raises production costs, they also represent a tangible commitment to reducing emissions and underscore that transitioning to cleaner energy systems often entails higher near-term expenditures. Across both scenarios, the levelized cost of waste treatment (LCOWT) spans 0.081–0.236 USD/kg of waste. Global warming potential (GWP) ranges from −0.191 to 0.662 kgCO₂-eq/kg of feedstock for Scenario 1, and 0.123 to 0.746 kgCO₂-eq/kg for Scenario 2. This work provides the first integrated assessment of such a hybrid WtE system, offering new insights for sustainable waste valorisation. The proposed novel designs support future detailed engineering studies and inform policymaking for low-carbon waste management.