Role Transformation of Incineration Plants in Carbon Emissions from Municipal Solid Waste Treatment after Source Classification.

The rapid proliferation of incineration plants has rendered their carbon emissions a substantial contributor to urban carbon emissions. Municipal solid waste classification presents waste-to-energy plants with challenges and opportunities. Monitoring nine Shenzhen incineration plants (2018-2022), we employed Monte Carlo simulations for sensitivity analysis and constructed response surface models to derive quantitative emission reduction pathways. Results indicate the plastic incineration proportion rose to 27.6%, increasing direct emissions and carbon substitution credits from electricity. Reducing plastic by 1% cuts emissions by approximately 17.38 kg CO₂-eq/t. Plastic should maintain below 34% considering synergistic effects among dominant emission determinants: plastic composition, grid carbon intensity, and electricity output. Singular interventions targeting plastic reduction or energy efficiency improvements have limited mitigation potential. A comprehensive mitigation scenario combining efficiency improvement, combined heat and power, plastic waste reduction, enhanced recycling, and Bioplastic substitution enables net negative emissions under future low-carbon grids. This study highlights that, systemic transformation from carbon source to carbon sink necessitates coordinated actions across multistakeholder.