Perspectives of oxy-coal power plants equipped with CO2 capture, utilization, and storage in terms of energy, economic, and environmental impacts

초록

CO2-free power plants (PPs) with renewable electricity have promising sustainability implications, but the impact of their widespread use is yet to be determined. Here, the effect of an oxy-coal PP equipped with CO2 capture, water electrolysis, and CO2 methanation on electricity efficiency, CO2 emission rate, CO2 capture cost, and global surface temperatures (Tg) was investigated. By exploiting surplus electricity from renewable sources for electrolysis, we estimated that 5 % of the CO2 emitted from the coal PP was methanized. The process flow diagram of a 500 MWe decarbonized oxy-coal PP was constructed and its impact on energetic, economic, and environmental values was evaluated. The results were applied to a model of the global carbon cycle to predict Tg considering the prospective global population and carbon emission rate (rff) of fossil fuels by 2050. An 80 % replacement of conventional coal PPs worldwide by decarbonized oxy-coal PPs contributed to reducing rff by 6.1 GtCO2/y in 2050 and lowering Tg by 0.09 degrees C. The additional capital cost to replace 80 % of conventional coal PPs with decarbonized oxy-coal PPs, including associated geological storage costs, was estimated to be $43/tCO2. This study elucidates the promise and limitations of coal PPs designed for CO2 capture, utilization, and storage (CCUS). Combining CCUS technologies with global warming estimates can be extended to examine the economic and climatic impact of CCUS under various CO2 emission sources.

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