Assessing the carbon reduction potential of municipal solid waste incineration at the county level in China

Municipal solid waste (MSW) incineration plants play a crucial role both in waste-to-energy sector and “Zero-waste Cities” construction in China. As the number and capacity of waste incineration plants (WIPs) are increasing rapidly, their expansion process and carbon reduction effect in history and future deserve in-depth research. This study examines the historical and future expansion of WIPs and their carbon reduction potential at the county level. We employ a machine learning framework combining two models: a Bayesian neural network (BNN) model to predict the probability of new WIP allocation and an explainable machine learning model to identify key factors driving county-level carbon emissions from waste disposal. It finds that the growth of WIPs from 202 to 902 during 2015-2022 has significantly reduced carbon emissions from 129.0 Mt CO 2 -eq to 91.1 Mt CO 2 -eq. Based on the BNN model, there will be 1,408 WIPs serving 2,492 county-level administrative units in 2035. The RF model with feature analysis demonstrates that landfill ratio, incineration ratio, population, and geographic location primarily influence the carbon emissions of waste disposal at the county level. Scenario analysis shows the temporal and spatial distribution of carbon reduction potential: the north and central regions have the largest carbon reduction potential in the country due to the rapid growth of WIPs, while a shift in spatial priority for carbon reduction is identified from municipal districts to counties. The findings provide targeted insights to address regional imbalances and guide infrastructure planning towards sustainable waste management and the low-carbon transition. • Integrating waste disposal and waste incineration plant (WIP) data to estimate carbon emissions. • Identifying features of counties’ carbon emissions of waste disposal by machine learning models. • Scenario analysis based on Shared Socioeconomic Pathways and WIP prediction at county level. • Assessing carbon reduction potential of waste incineration in different groups toward 2035.