Yet, simple as the idea may sound, considerable research is still needed to be certain the technique would be safe, effective and affordable.

Scientists need to figure out which kinds of rock and soil formations are best at holding carbon dioxide. They need to be sure the gas will not bubble back to the surface. They need to find optimal designs for new power plants so as to cut costs. And some complex legal questions need to be resolved, such as who would be liable if such a project polluted the groundwater or caused other damage far from the power plant.

Major corporations sense the possibility of a profitable new business, and G.E. signed a partnership on Wednesday with Schlumberger, the oil field services company, to advance the technology of carbon capture and sequestration.

But only a handful of small projects survive, and the recent cancellations mean that most of this work has come to a halt, raising doubts that the technique can be ready any time in the next few decades. And without it, “we’re not going to have much of a chance for stabilizing the climate,” said John Thompson, who oversees work on the issue for the Clean Air Task Force, an environmental group.

The fear is that utilities, lacking proven chemical techniques for capturing carbon dioxide and proven methods for storing it underground by the billions of tons per year, will build the next generation of coal plants using existing technology. That would ensure that vast amounts of global warming gases would be pumped into the atmosphere for decades.

The highest-profile failure involved a project known as FutureGen, which President Bush himself announced in 2003: a utility consortium, with subsidies from the government, was going to build a plant in Mattoon, Ill., testing the most advanced techniques for converting coal to a gas, capturing pollutants, and burning the gas for power.

The carbon dioxide would have been compressed and pumped underground into deep soil layers. Monitoring devices would have tested whether any was escaping to the atmosphere.