Expert assessments of retrofitting coal-fired power plants with carbon dioxide capture technologies

Abstract

Carbon dioxide capture and storage is an emerging set of technologies that can contribute to significant reductions in CO2 emissions. However, a substantial amount of uncertainty belies the technical and economic feasibility of capturing CO2 at commercial scale. This study explores the uncertainties associated with carbon dioxide capture technologies, with a specific focus on retrofitting existing coal-fired power plants. 13 respondents with expertise in post-combustion and oxy-fuel combustion capture systems responded to an extensive questionnaire and provided their opinions on present status and future expected performance and costs for amine-based systems, chilled ammonia process, and oxy-combustion. Expert elicitation, a formal protocol for obtaining probabilistic judgments on a subject with insufficient data, was the primary method used to establish best estimates and 95% confidence limits of the energy penalties associated with the technologies under focus. Additionally, this paper presents observations based on the aggregated responses for technology maturity, ideal plant characteristics for early adopters, and the extent to which R&D and deployment incentives will impact costs. The results show a general consensus that amine-based systems are closer to commercial application, but potential for improving performance and lowering costs is limited; chilled ammonia and oxy-combustion contain greater potential for cost reductions, but not without greater uncertainty in regard to scale and technical feasibility. A cost model using expert estimates of expected energy penalties was developed to establish 2030 projections of CO2 capturecosts for amine-based systems. Results from the model indicate that under the reference case(current trends in RD&D), the energy penalty reduction equates to an 11% decrease in annual energycosts. In the best case scenario(best results under an enhanced RD&D policy), the annual energy savings are 29% and the CO2capturecost decreases 16% from $55(in the reference case)to $46per ton of CO2(2006 dollars).