Life Cycle Water Use for Oxy Fuel Combustion Power Generation with CO2 Capture and Storage

The water scarcity is becoming a growing concern. Regarded as a potential CO emission mitigation technology for coal-fired power plants, oxy-fuel combustion, a typical CCS technology, theoretically consumes a large amount of water, which increases the severity of the water scarcity. Therefore, revealing the water use of oxy-fuel coal-fired power plants is of great importance for the deployment of CCS technologies under water resource constraint in the future. In this respect, the aim of this study is to evaluate the life cycle water use of oxy-fuel CO capture, transport and storage via a 600 MW coal fired oxy-fuel power plant in China. By using a tiered hybrid life cycle assessment, both direct and indirect water use are calculated. Results show 22.9L H O/kg of CO and the oxy-fuel power plant stage dominates the total water use, while the water intensity for power generation is calculated as 3233.3 L H O/MWh, which is higher than the conventional power plants. Sensitivity analysis is performed in this research and indicates that the variation of tap water use affects the water intensity immensely. Furthermore, the use of the membrane method for air separation decreases the overall water use 14.21% respectively. China is continually increasing its efforts to reduce carbon emissions due to both domestic and international pressure. Hence the development and implement of the CCS technology is of great urgency. At the end of this study possible solutions such as using wasted or discarded wind power for the separation of oxygen to minimize water use in oxy-fuel power plant stage are put forward.