Oct 15 - USA TODAY

The Environmental Protection Agency has announced plans that could encourage the storage of carbon dioxide emissions deep underground, an emerging "clean" energy technique that energy experts say will help reduce the greenhouse gases that cause global warming.

Capturing carbon dioxide from coal-fired power plants before it's emitted and then injecting it thousands of feet into the ground is becoming an increasingly viable option, according to a Massachusetts Institute of Technology study released in March.

The study said storing emissions underground would be "the critical enabling technology" to achieve the conflicting goals of curbing greenhouse gases and meeting energy needs. "Absent a technological breakthrough that we do not foresee, coal, in significant quantities, will remain indispensable" in power production.

Coal-fired power plants, the source of almost half the nation's electricity, emitted about one-third of all U.S. carbon dioxide emissions in 2005, according to the Department of Energy.

If the regulation EPA will propose settles issues such as preventing leaks and monitoring storage sites, it might remove one obstacle to the commercialization of underground carbon dioxide storage.

"The private sector needs certainty when making investments," says EPA associate deputy administrator Jason Burnett. The Energy Department is also investing: It announced last week it will spend $197 million over 10 years for underground carbon sequestration.

The department estimates that North America can hold about 3.5 trillion tons of carbon dioxide beneath the Earth's surface, theoretically enough to store U.S. emissions for centuries.

"Oil and gas have been trapped forever, so you know that the zones that it came from have the ability to hold the gas," says Mark Stewart, a geologist at the University of South Florida. "What's holding everything back is a very uncertain regulatory environment." The EPA expects to propose the rules next summer.

Storing carbon dioxide underground is the last step in a process that could prevent more than 90% of a given power plant's emissions from reaching the atmosphere.

The technology for removing the carbon dioxide before it's emitted has existed for decades. For example, the Great Plains Synfuels Plant in North Dakota captures its carbon dioxide, then sells it and pipes the gas to oil companies in Canada. Those firms inject the gas thousands of feet underground, which pushes remaining pockets of oil toward the fields' surface.

Also needed, says Rich Furman, an independent energy technology consultant, is a carbon tax or a cap and trade program to make it costly to emit carbon dioxide. Only then, he says, will utilities and other industries store carbon dioxide on a scale large enough to substantially reduce global emissions.

"Right now, since there are no regulations requiring removal of CO, it's only being done where they can make a profit by reselling it," he says.

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