CO2 Capture and Storage Gains a Growing Foothold

[OKIsItJustMe]

http://e360.yale.edu/content/feature.msp?id=2240

18 Feb 2010: Report

CO2 Capture and Storage Gains a Growing Foothold

The drive to extract and store CO2 from coal-fired power plants is gaining momentum, with the Obama administration backing the technology and the world’s first capture and sequestration project now operating in the U.S. Two questions loom: Will carbon capture and storage be affordable? And will it be safe?

by david biello

On a placid bend of the Ohio River in West Virginia sit two coal-fired power plants. The Philip Sporn Plant boasts four boilers from the 1950s, surrounded by mountains of coal and a series of man-made lakes to contain the toxic residue of its coal-burning. A faint haze emanates from its main smokestack, the only visible sign of the thousands of tons of acid-rain-forming sulfur dioxide, smog-forming nitrogen oxides, and climate-warming carbon dioxide it emits each day, a consequence of the plant’s complete lack of pollution-control technologies. The 1,100 megawatts of electricity it produces will never benefit from such controls, as they are too expensive to install on the multiple small boilers, according to the plant’s owner, American Electric Power.

But just beyond Sporn’s waste ponds stands the steaming cooling tower of American Electric’s Mountaineer Power Plant, which burns 12,000 tons of coal a day to produce steam in a single massive boiler and generate up to 1,300 megawatts of electricity. Roiling white water vapor billows out of its 100-story smokestack, a visible sign of the scrubbers and other technology that remove as much as 98 percent of the plant’s sulfur dioxide emissions and 90 percent of its nitrogen oxides.

And to top it off, since October, an oversized chemistry set employs baker’s ammonia (ammonium carbonate) to strip more than 90 percent of the CO2 from a small portion of the Mountaineer plant’s waste gas and turn it into ammonium bicarbonate. Heat and pressure in another part of the carbon-capture machine turn that back into baker’s ammonia, delivering a nearly pure stream of CO2 gas that is compressed into a liquid and pumped into two wells that drop 1.5 miles beneath the earth. There, the captured CO2 is stored permanently between grains of rock.

If Sporn represents the dirty past of coal-fired electricity generation, Mountaineer is the future — the first power plant in the world to both capture and store underground any part of its CO2 emissions. At this point, Mountaineer stores less than 2 percent of the more than 500,000 metric tons of CO2 pumped out each month by the power plant, which generates enough electricity for 1 million American homes.

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