Health Implications and Deployment Potential of Post-Combustion CCS in the U.S. Power Sector

Post-combustion carbon capture and storage (CCS) can substantially reduce CO₂ emissions from coal and natural gas combined cycle (NGCC) power plants before entering the atmosphere. Little is known about the maximum potential of CCS across U.S. thermoelectric power plants or the potential air pollution and resulting human health effects associated with its retrofit. Integrating CCS affects other air pollutant emissions as well. The flue gas must be adequately pretreated to remove air pollutants that react with solvents to cause losses, while solvents can break down and lead to ammonia (NH₃) emissions. In this study, we explore the air pollution and CO₂ emissions impacts of national-scale post-combustion CCS adoption at coal and NGCC plants in the U.S. using monoethanolamine (MEA) and CESAR1 as representative first- and second-generation solvents, respectively. We quantify the effects of CCS on human health using the InMAP Source-Receptor Matrix (ISRM), which transforms emissions of primary PM_2.5 and precursors of secondary PM_2.5 into total changes in concentrations. This analysis brings together four main components in an integrated assessment model: (1) power plant CCS retrofit scenarios for coal and NGCC plants, (2) grid mix and generation scenario modeling, (3) plant-level emissions changes, and (4) the quantification of human health and greenhouse gas (GHG) emissions impacts.

If CCS retrofits are only viable on newer facilities, 97% of NGCC plant emissions are addressable compared to only 27% of coal plant emissions. Potential human health benefits of CCS retrofits are concentrated at coal plants, where the net benefits of added flue gas pretreatment are substantial, regardless of solvent. NGCC plants, however, require NH₃ emissions controls and/or modern solvents, as using MEA without NH₃ emissions controls could increase net human health burdens fourfold. This study shows that post-combustion CCS using amine-based solvents can have human health co-benefits or co-burdens depending on the solvent choice, fuel type, existing flue gas concentration, and presence of NH₃ emission controls. Further, we provide policy-relevant recommendations for achieving greenhouse gas reduction benefits while limiting air pollution-related human health effects.