Carbon capture and sequestration isn't sexy. Too many syllables, for one thing. For another, it sounds vaguely like putting a piece of burnt toast in a black box, or maybe a war-on-terrorism interrogation technique at Guantanamo Bay.

But as the nation and world grapple with how to reduce carbon dioxide and other greenhouse gas emissions that contribute to global climate change, the unproven but promising technology may one day rescue the coal industry and the electric utilities that depend on coal, and go a long way toward stabilizing a warming world.

It's the process of capturing carbon dioxide before it is emitted into the atmosphere, compressing it into a liquid and then pumping it underground -- into depleted oil and gas reservoirs, deep coal seams, saline formations and deep below the ocean floor -- where, theoretically, it will do much less harm.

Man-made carbon dioxide emissions, primarily from the burning of fossil fuels for power generation and transportation, have increased from an insignificant level two centuries ago to more than 33 billion tons a year worldwide, 8.8 billion tons of that from the United States.

The higher emissions have increased the amount of atmospheric greenhouse gases, which trap radiant heat from the sun and cause global warming and potentially unhealthy changes in regional climates.

"I think there's increasing recognition by the utility industry that this issue is not going away, and it is looking at how to deal with greenhouse gas management instead of if it should deal with it," said Carl Bauer, director of the U.S. Department of Energy's National Energy Technology Laboratory in Bruceton, near South Park. "I think the industry as a whole is increasingly realistic about this."

Government, academic and industry research facilities are exploring the existing technology and developing new methods, reviewing regulatory needs and conducting research with an eye to reducing the considerable costs of carbon sequestration that now could as much as double electric bills.

In large part because of cost considerations, widespread commercial carbon capture and sequestration might not happen for two decades, Mr. Bauer said at the sixth annual Conference on Carbon Capture and Sequestration in Pittsburgh last week.

"This is a huge problem that will be very difficult to solve," Mr. Bauer said "The economics are challenging. We'd like to get the costs down so that the increase in electric bills will be about 8 percent, but we're not there yet. A number of capture innovations are being developed but most are still at laboratory scale."

The problems caused by man-made carbon dioxide emissions, which account for 80 percent of all greenhouse gas emissions in the United States, are much bigger.

Tom Sarkus, DOE FutureGen Project director at Bruceton, said carbon sequestration will improve the nation's "energy security."

"If you don't have sequestration, you could extinguish coal use," Mr. Sarkus said. "Sequestration provides a technology-based way to tackle climate change, in much the same way that we used technology to tackle the acid rain problem."

David Hawkins, climate director for the Natural Resources Defense Council and a conference keynoter, said climate change is such an important environmental issue that a carbon collection and sequestration program should begin immediately and no new power plants should be built unless they are carbon- sequestration-ready.

Others say that before that happens, much additional research is needed to reduce costs, identify underground sites where the liquid carbon dioxide can be safely stored, improve monitoring and protect groundwater.

Injecting carbon dioxide could help recover oil and natural gas from underground formations, but it could also bubble up, forcing salty brine water to the surface and polluting streams, or convert to an acid in groundwater. Also a concern is that earthquakes have been reported in places where deep-well injection has been used.

New laws, regulations and standards are needed to address the hazards, risks and liabilities of injecting large volumes of such a buoyant liquid underground, said Edward Rubin, a professor at Carnegie Mellon University's Department of Education and Public Policy.

"Until we build and operate large scale carbon sequestration projects, we will not have the data needed to evaluate a number of those critical issues," Mr. Rubin said.

Sean Plasynski, DOE's Sequestration Technology manager in Bruceton, said the department is spending $100 million this year on research and development, and has established seven regional partnerships encompassing 41 states and four Canadian provinces to investigate carbon capture and storage technologies.

"There's a lot of science going on. We're working with a lot of agencies to help set policy and regulations," Mr. Plasynski said. "We have to do some pilot and demonstration projects so we can make correct decisions going forward."

Theresa Pugh, director of environmental services for the American Public Power Association, said a carbon sequestration strategy is just one of many research paths the industry needs to explore before investing in costly carbon sequestration.

"Sequestration may be one of the many technologies needed to mitigate carbon, but we don't know if the technology works, if we can afford it, or what it means to electric bills," Ms. Pugh said. "We know we're going to be dealing with congressional efforts to constrain carbon in some form."

Legislation aimed at controlling greenhouse gas emissions is under review in Congress, and the U.S. Environmental Protection Agency is supposed to be putting together regulations for carbon sequestration, Mr. Bauer said.

"The DOE has put a big investment into developing the technology and understanding carbon storage," Mr. Bauer said. "I think, given Congress' position and the recent decision of the U.S. Supreme Court, that we will see the administration aggressively addressing the regulatory side."

While industry, academic and governmental interest in carbon sequestration is growing, Mr. Bauer admitted that the general public "isn't engaged" on the issue.

"We've been talking about it for at least a decade but we're still struggling to get our head around it," he said. "Challenges exist. Implementation is highly probable, but if we mess up and people lose faith, it will set back this opportunity to use this technology."