Evaluation of greenhouse gas emissions and the feed-in tariff system of waste-to-energy facilities using a system dynamics model

Abstract

This study used a system dynamics model to evaluate the potential greenhouse gas (GHG) emissions from different waste-to-energy (WTE) facilities such as landfill sites, WTE plants, anaerobic digestion (AD)-based WTE plants, and material recovery facilities. On average, landfilling and incinerating 1 t of municipal solid waste (MSW) produced 1807.0 kg carbon dioxide (CO2)-eq/t and 373.3 kg CO2-eq/t of GHG emissions, respectively. Recycling waste helped to mitigate the GHG emissions and the output to merely 78.9 kg CO2-eq/t. Excess emission of 1848 t CO2-eq/y GHG accounted for the 3 percentage point difference in the electricity generation efficiency of WTE plants (25%) and AD-based WTE plants (28%). Therefore, it is suggested that the priority for MSW treatment should be AD-based WTE plants, WTE plants, and stand-alone AD systems (in descending order) to ensure maximum electricity generation and mitigation of GHG emissions. GHG emissions were most sensitive to the recycling rate, proportion of dry matter, and electricity coefficient. The predicted benefit to cost ratios of WTE and AD-based WTE plants in 2049 were 2.29 and 3.92, respectively. Based on these data, this study inferred that the feed-in tariff system, despite its high capital costs, must be encouraged to reduce the economic burden of WTE facilities.