This report reviews recent studies on the efficiency penalty of coal-fired power plants with CCS (Carbon capture and storage or sequestration). An efficiency penalty, which represents a net decrease in the power efficiency caused by the CO2 capture and compression process, can be estimated using process simulation that considers factors such as the power generation steam cycle, coal type, and CO2 capture and compression process. According to previous research, the efficiency penalty for current applications was about 10%. The ratio of efficiency penalty caused by CO2 capture to the total efficiency penalty was about two thirds. It appears that while the types of power plant and coal had little influence on efficiency penalty, the CO2 capture technology was critically important. By reducing the regeneration energy of the CO2 scrubbing solvent by 1 GJ/t-CO2, an approximate 2% efficiency improvement can be expected.