CO2 emissions reduction from coal-fired power generation: a techno-conomic comparison

Carbon capture and storage (CCS) represents a key solution to control the global warming reducing carbon dioxide emissions from coal-fired power plants. This study reports a comparative performance assessment of different power generation technologies, including ultrasupercritical (USC) pulverized coal combustion plant with postcombustion CO2 capture, integrated gasification combined cycle (IGCC) with precombustion CO2 capture, and oxy-coal combustion (OCC) unit. These three power plants have been studied considering traditional configuration, without CCS, and a more complex configuration with CO2 capture. These technologies (with and without CCS systems) have been compared from both the technical and economic points of view, considering a reference thermal input of 1000 MW. As for CO2 storage, the sequestration in saline aquifers has been considered. Whereas a conventional (without CCS) coal-fired USC power plant results to be more suitable than IGCC for power generation, IGCC becomes more competitive for CO2-free plants, being the precombustion CO2 capture system less expensive (from the energetic point of view) than the postcombustion one. In this scenario, oxy-coal combustion plant is currently not competitive with USC and IGCC, due to the low industrial experience, which means higher capital and operating costs and a lower plant operating reliability. But in a short-term future, a progressive diffusion of commercial-scale OCC plants will allow a reduction of capital costs and an improvement of the technology, with higher efficiency and reliability. This means that OCC promises to become competitive with USC and also with IGCC.