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Can Coal Be Clean?

October 29, 2010

The term “clean coal” has been used and abused, so let’s look at whether coal can be clean, or nearly so.

The existing fleet of coal-fired power plants has a thermal efficiency of 32% (HHV), and produces about 0.95 tons of CO2 per mega-watt-hour (MWh).

For comparison, natural gas-fired power plants produce around 0.6 tons of CO2 per MWh.

New ultra-supercritical pulverized coal-fired power plants are a terrific improvement over traditional pulverized coal-fired plants.

Ultra-supercritical plants have a thermal efficiency of 44%, which is a 35% improvement over traditional plants.

Ultra-supercritical plants with an efficiency of 44% operate at very high temperatures and pressures, specifically 1112° F and 4350 psi.

It’s anticipated that temperatures and pressures can be increased further, and that a thermal efficiency of 46% (HHV) can be achieved in the next several years. These would be referred to as Advanced Ultra-supercritical plants.

Both the United States and Europe have development programs designed to produce the metals needed for boilers and steam turbines to operate at higher temperatures and pressures.

Finally, ultra-supercritical plants with appropriate controls for capturing particulates and mercury can operate with extremely low levels of NOx, SOx and particulate and mercury emissions.

While not quite as clean as natural gas, ultra-supercritical plants are nearly as clean, and meet or better all EPA emission standards, except, possibly, any standard the EPA might establish for CO2.

 As you know, I do not believe CO2 emissions are a threat, but even if they were, ultra-supercritical pulverized coal-fired plants are nearly as good as natural gas, and produce only slightly more CO2 than natural gas plants.

CO2 emissions from ultra-supercritical plants are around 0.66 tons of CO2 per MWh, compared with 0.6 tons of CO2 per MWh for natural gas power plants.

Environmental extremists have said that natural gas is a bridging technology until carbon capture and sequestration (CCS) is available, in which case ultra-supercritical plants should also be an acceptable bridging technology.

Actually, ultra-supercritical pulverized coal-fired power plants should be the accepted norm for new power plant construction. They will produce electricity cheaply, and keep the cost of electricity down for families and industry.

While there is only one ultra-supercritical plant being built in the United States, China is building dozens. China understands the importance of producing inexpensive electricity while cutting emissions.

© Power America, 2010. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Power America with appropriate and specific direction to the original content.

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