Techno-economic and environmental evaluation of a supercritical CO2 coal-fired circulating fluidized bed boiler power generation

Abstract

Replacing the steam cycle with the supercritical CO2 (S–CO2) cycle applied in coal-fired power generation is a demonstrated approach to greatly improving efficiency and flexibility. This promotes carbon reduction through efficient use of fossil fuels and improving utilization rate of renewable energy by deep peak shaving. Unlike most studies focusing on conceptual design and efficiency-based investigation, the techno-economic and environmental performance evaluations of the S–CO2 power generation are still rare and undiscovered. In this paper, techno-economic and environmental investigation of a 600 MW S–CO2 coal-fired circulating fluidized bed (CFB) boiler power plant is firstly considered. During this process, a series of economic cost and environmental assessment models and methods integrated with process simulation were proposed. The results showed that there exits an optimum turbine inlet temperature of 635 °C from the techno-economic perspective. The total cost of the S–CO2 power plant increases by ∼10 % and the cost of electricity (COE) decreases by 4.6 % compared to the same-capacity steam plants. The life cycle assessment (LCA) environmental impact potential of the S–CO2 power is far less compared to steam power plants. Its environmental impact is greatest on a global scale and relatively low on a regional scale, such as a country or region.