Another challenge: capturing gases to be buried

Companies and cities are pushing to build coal-fired power plants that emit no greenhouse gases.

By Mark Clayton | Staff writer of The Christian Science Monitor

from the July 31, 2007 edition

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Odessa, Texas - Against a pancake-flat horizon dotted by nodding oil pumps, Hoxie Smith sweeps his hand across 600 acres where he expects the nation's first "clean coal" power plant to rise from a vista of mesquite and prickly-pear cactus.

He's leading the Odessa, Texas, bid for a joint public-private project to build a revolutionary energy source that would emit virtually no greenhouse gases.

"I think we're on the verge of an energy renaissance in this country," says Mr. Smith. "Texas is going to lead the way."

Several Lone Star initiatives are under way. A second Texas city is vying for the project. In the private sector, at least a dozen proposals using similar technology have surfaced in the state in the past year. If the race to build climate-neutral coal-fired plants is heating up here in the home of Big Oil, it's a sign that America's energy industry is eyeing seriously new ways of producing power without warming the planet.

The idea is simple: Capture greenhouse gases before they go up the smokestack. Some promising technologies have already been developed. But several obstacles remain, key among them: storage and cost.

Scientists are hard at work here on the first challenge, trying to figure out if greenhouse gases can be stored safely and permanently underground. Texas' underground salt basins and old oil and gas fields are among the prime areas being considered to hold the nation's waste carbon-dioxide (CO2) and other greenhouse gases.

The second challenge is to find cost-effective ways to trap those gases in power plants before they go up the smokestack.

At the moment, the leading technology to do this is coal gasification, otherwise known as Integrated Gasification Combined Cycle or IGCC. Instead of burning coal, an IGCC system heats it up with steam until it breaks apart into a concentrated stream of gases, including CO2. The CO2 is captured while other gases, including hydrogen, are burned to produce electricity.

Plants are costlier to build and run

Currently, building a new IGCC plant costs about 20 percent more than a conventional coal-fired power plant, industry experts estimate. It's also more expensive to run. Even without CO2-capture, electricity produced by IGCC costs 5 to 11 percent more to make, according to a study by the Massachusetts Institute of Technology. When capturing CO2 for sequestration below ground, the cost jumps to 30 percent or more above a standard power plant.

But big utilities here in the United States and elsewhere are interested in IGCC for three related reasons. First, the alternatives are not particularly attractive. The spike in natural-gas prices has made gas-fired turbine plants less attractive. Nuclear plants are controversial, costly, and take years to site and get approved, at least in developed countries. That leaves conventional coal-fired power plants, which face an uncertain future because their greenhouse-gas emissions could make them much more costly to operate if governments enact climate legislation that puts a price on carbon.

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