Environmental assessment of carbon capture and storage (CCS) as a post-treatment technology in waste incineration.

Abstract

The effects of amending municipal solid waste incineration (MSWI) with carbon capture and storage (CCS) via MEA (Monoethanolamine) technology differ according to the air pollution control technologies and energy recovery systems. Electricity output reduces by one-third for power-only plants and halves for combined heat-and-power plants, while variations in heat recovery depend on the presence of flue gas condensation. MSWI with CCS can capture roughly 800kg of compressed CO2 per tonne of waste treated. Life cycle assessment (LCA) modelling of MSWI, with and without CCS, illustrates that despite energy penalties, CCS lowers its climate change impact. The difference in climate change impacts as a result of CCS amendment depends on the energy system in which MSWI operates. In a near-future energy system, MSWI with CCS reduces climate change impacts by 700kg CO2-eq/tonne wet waste compared to MSWI without CCS. The climate change saving of CCS became increasingly larger as the energy system became "greener"; the climate change saving ultimately approached the capture efficiency (85% of CO2 in the flue gas) multiplied by the carbon content of the waste converted to CO2. Sensitivity analysis showed that capture efficiency was the main factor affecting the overall results, with increasing importance in non-fossil fuel-based energy systems. Likely changes in residual waste composition, as source segregation and collection systems improve, had only minor effects on the environmental benefits of CCS. The effects of CCS amendments on 13 other impact categories were marginal compared to the effects of different MSWI configurations.