Techno-economic evaluation of CO2 capture and storage retrofit in decarbonizing different thermal power plants: A case study in China

Abstract

Given that thermal power plants are the dominant mode of power generation in China, decarbonization from thermal power plants is significant to protect the global climate from further warming. CO2 capture and storage (CCS) is one of the most promising approaches for mitigating CO2 emissions; therefore, studies evaluating the effect of CCS retrofit on thermal power plants are urgently required. This study selected coal-fired power plant (CFPP) and natural gas combined cycle power plant (NGCC) as the representative technologies for thermal power plants, and proposed system models for their integrations with CCS. A comprehensive evaluation system was established using different metrics such as specific CO2 emission (CO2 emission per kWh), net electric efficiency, levelized cost of electricity (LCOE), and cost of avoiding CO2 emission (COAE). The detailed effects of fuel price fluctuations, technological advances, and different technology combinations on key metrics were analyzed, in order to propose policy recommendations for the decarbonization of China's thermal power plants using CCS technology. The following results were obtained: (1) The use of CCS to reduce CO2 emissions from thermal power plants will lead to a significant increase in LCOE. Each 100 g/kWh reduction in specific CO2 emission will result in 11 %–14.5 % increase in LCOE for CFPP + CCS, and 9.5 %–13.5 % increase for NGCC + CCS. (2) Technological advances toward reducing specific heat consumption for CO2 capture should be strongly promoted to reduce LCOE. Each 0.4 GJ/t reduction in specific heat consumption will result in an approximately 0.066 CNY/kWh reduction in LCOE for CFPP. (3) Both CFPP + CCS and NGCC + CCS exhibit potential for decreasing COAE below 600 CNY/t, although the technologies to meet this threshold are not currently realistic at higher fuel prices.