Life cycle assessment of four waste-to-energy plant configurations equipped with post-combustion carbon capture and storage

When equipped with Carbon Capture and Storage (CCS), Waste to Energy plants can directly reduce fossil carbon dioxide emissions from post-recycling residual waste while also re-capturing atmospheric carbon dioxide via the permanent geological storage of biogenic carbon uptake. Increasingly, municipal solid waste (MSW) is treated by incineration in dedicated plants where the heat from combustion is recovered via electricity generation and district heating. Post-combustion CO2 capture with amine-based technology can achieve ultra-high CO2 capture rates such that CO2 generated in the combustion of the waste feedstock results in no direct CO2 emissions to the atmosphere. The large biogenic content of residual waste feedstock presents a particular opportunity for bioenergy with CCS (BECCS).

A life cycle assessment LCA of the environmental impacts of a state-of-the-art WtE facility with CCS at ultra-high capture rates shows that adding CCS can provide a significant improvement in climate change impact, and achieve a net climate benefit. Without significant burden shifting to other environmental impact categories, the climate change impact of a WtE plant treating 500 tpd of MSW is reduced from 388 kg CO2eq/t MSW to 483 kg CO2eq/t MSW, with the biogenic CO2 captured and permanently stored accounted as negative CO2 emissions. When the avoided greenhouse gas emissions from electricity, district heating and material recovery are also included, the climate impact is 777 kg CO2eq/t MSW for a power-only WtE plant exporting 9.6 MWe, and 907 kg CO2eq/t MSW for a combined heat and power WtE plant exporting 6.2 MWe and 18.5 MWth.