Post combustion carbon capture and storage in existing coal power plant : importance and recent development

Carbon capture and storage (CCS) is considered as one of the most promising options in the near and medium term to reduce CO2 emissions, particularly from power plants that use fossil fuels. Among the fossil fuel power plants, coal based ones have relatively larger emission than oil and gas and globally they contribute very significantly to emissions. Yet, the use of coal for producing electricity in future is expected to be as dominant as in the present time due to its wide availability as a cheap source of primary fuel. Adoption of CCS technology for coal power plant application is, therefore, highly emphasized by all countries and governments. Existing plants installed without carbon capture are a very big source of emission. As plants without capture are being installed to meet the growing demand for electricity, they are adding more to the already existing emission. Therefore, CCS application in existing plants is seen to have great impact in reducing CO2 emission in atmosphere. CCS technology is still developing and some approaches of capture, namely pre combustion, post combustion and oxy fuel combustion have, already, been piloted or demonstrated. Post combustion carbon capture is the likely economic option for retrofitting existing plant. With present technology options and operations, the CCS consumes a significant amount of energy which is supplied from the power generation cycle. It causes a reduced amount of energy (electricity) output available or demanding additional energy (as input) to generate same amount of energy (electricity) output. This (energy consumed by CCS) is termed as energy penalty and it ultimately raises the cost of power generation. This paper reviewed opportunities for reducing such energy penalty, in other words, improving overall energy efficiency of the existing coal power plant integrated with carbon capture. Indications are that there are further opportunities to improve the overall efficiency of a properly integrated power plant with carbon capture.