Pssst. Want to get rid of CO2? Try burying it.

(Fortune Magazine) -- Can a coal-fired power plant completely eliminate carbon-dioxide emissions? That's what Swedish energy company Vattenfall is hoping to prove with a pilot project under construction in Germany that promises to be the world's first emissions-free carbon power-generating plant.

The $62 million, 30-megawatt facility, scheduled to go into operation by mid-2008, makes use of oxyfuel technology, in which coal is burned in pure oxygen instead of air. That leaves the resulting emissions nitrogen-free and easier to clean and store. Once the plant in Schwarze Pumpe, south of Berlin, is fully operational, the plan is to compress the CO2 into liquid and inject it into porous rock about a kilometer below ground. Over time the carbon dioxide is expected to sink, dissolve in saline aquifers, and mineralize into carbonates. "In a thousand years, we can start selling Vattenfall marble," jokes company spokesman Staffan Görtz.

Of course, if the gas escapes to the surface, Vattenfall won't be selling marble futures; it will need to buy marble tombstones. "If the CO2 leaks out, the least problem would be further adding to the greenhouse effect," Görtz notes. "The key issue would be the risk of suffocating, since CO2 is heavier than air and will stay close to the ground."

Injecting CO2 deep underground is the most promising method of what is known as carbon sequestration. The technology is already being used by Shell and other oil companies to enhance production at offshore oil and gas fields.

Research into reducing CO2 emissions from burning coal is being carried out in many industrialized countries as a result of a growing awareness about global warming. In the two years it will take to build the Vattenfall plant, 50 billion tons of CO2 will be emitted worldwide. "Vattenfall's project is definitely on the cutting edge of carbon removal," says John Grasser, a U.S. Department of Energy spokesman. "There's less pollution using oxyfuel." Other methods of capturing CO2 include cleaning emissions after combustion and gasifying coal to get hydrogen for combustion.

"With regard to costs, oxyfuel is currently the most promising method for capturing carbon dioxide at our existing power plants," says Görtz. Even though the technology is expensive, he adds, the cost of generating power will be cheaper than it would be if Vattenfall paid for emitting CO2 under current European Union regulations-about 17 euros a ton.

Vattenfall CEO Lars Josefsson says his company, which is owned by the government of Sweden and emits 90 million tons of CO2 into the atmosphere each year, has a particular responsibility. "Climate change," he says, "is a reality we have to face."