A co-gasification strategy of residual municipal solid waste and biomass for electricity generation optimization and carbon reduction

Upon waste classification, large volumes of heterogeneous residual municipal solid waste (rMSW) present challenges for the low-carbon management of waste-to-energy. While co-gasification is a more efficient strategy for waste-to-energy utilization than mono-gasification, the collection and transportation of substrates emit additional greenhouse gases, resulting in a net positive and high carbon footprint in energy production. This study proposes a bi-level multi-objective optimization model that presents a co-gasification strategy of biomass and rMSW involving the authority and gasification plants. In this model, the co-gasification strategy is determined by operators based on the power generation efficiency, while the government’s carbon reduction goal interferes with the plant’s operation. A practical case study is subsequently investigated to demonstrate the applicability of the methodology in co-gasification deployment and resource recovery improvement; analyses related to carbon policy application are conducted by adjusting associated parameters. It was identified that the carbon tax policy encourages a co-gasification strategy more than a rigid emission cap regulation. Pricing carbon emissions at 80 CNY/tonne could present the lowest carbon emissions intensity and ensure the operating profit of each gasification plant. Based on the observations made, a set of targeted recommendations encompassing policy, technical, and market aspects is proposed for stakeholders.