Technical and economic feasibility evaluation of calcium looping with no CO₂ recirculation

Carbon capture and storage is expected to play a key role in decarbonisation of the power and industrial sectors, with calcium looping (CaL) being regarded as a well-developed technology that can reduce energy and economic penalties associated with mature technologies. Nevertheless, retrofits of CaL to coal-fired power plants result in net efficiency penalties of 5–8% points. The state-of-the-art CaL configurations assume that, similarly to oxy-fuel combustion systems, CO₂ needs to be recycled to moderate the temperatures in the calciner. This study aims to assess the feasibility of CaL with no CO₂ recirculation to the calciner via pilot plant testing and techno-economic analysis. The results collected during the experimental trials indicated that the temperatures inside of the calciner were within 930–950 °C, which were within the commonly reported operating temperature range of that reactor. Furthermore, the techno-economic analysis of the CaL retrofit to a conventional 580 MW_el coal-fired power plant indicated that operation of CaL without CO₂ recirculation will have a negligible effect on the net thermal efficiency of the entire system. Nevertheless, reduction in the size of the system resulted in a 21.7% reduction in the specific capital cost, and thus a 14.3% and 27.4% reduction in the levelised cost of electricity and cost of CO₂ avoided, respectively. Therefore, CaL with no CO₂ recirculation can be considered as a technically and economically feasible option to reduce the economic penalty associated with this emerging technology.