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

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