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Reassessing the Efficiency Penalty from Carbon Capture in Coal-Fired Power Plants

Supekar, Sarang D., Skerlos, Steven J.
Environmental Science & Technology 2015 v.49 no.20 pp. 12576-12584
carbon, carbon dioxide, carbon sequestration, coal, electricity, emissions, energy, greenhouse gases, heat, natural gas, pollutants, power plants, steam, transportation, wind power
This paper examines thermal efficiency penalties and greenhouse gas as well as other pollutant emissions associated with pulverized coal (PC) power plants equipped with postcombustion CO₂ capture for carbon sequestration. We find that, depending on the source of heat used to meet the steam requirements in the capture unit, retrofitting a PC power plant that maintains its gross power output (compared to a PC power plant without a capture unit) can cause a drop in plant thermal efficiency of 11.3–22.9%-points. This estimate for efficiency penalty is significantly higher than literature values and corresponds to an increase of about 5.3–7.7 US¢/kWh in the levelized cost of electricity (COE) over the 8.4 US¢/kWh COE value for PC plants without CO₂ capture. The results follow from the inclusion of mass and energy feedbacks in PC power plants with CO₂ capture into previous analyses, as well as including potential quality considerations for safe and reliable transportation and sequestration of CO₂. We conclude that PC power plants with CO₂ capture are likely to remain less competitive than natural gas combined cycle (without CO₂ capture) and on-shore wind power plants, both from a levelized and marginal COE point of view.