( While solar power and hybrid cars have...)Researchers examine carbon capture and storage to combat global warming

While solar power and hybrid cars have become popular symbols of green technology, Stanford researchers are exploring another path for cutting emissions of carbon dioxide, the leading greenhouse gas that causes global warming.

Carbon capture and storage, also called carbon sequestration, traps carbon dioxide after it is produced and injects it underground. The gas never enters the atmosphere. The practice could transform heavy carbon spewers, such as coal power plants, into relatively clean machines with regard to global warming.

''The notion is that the sooner we wean ourselves off fossil fuels, the sooner we'll be able to tackle the climate problem,'' said Sally Benson, executive director of the Global Climate and Energy Project (GCEP) and professor of energy resources engineering. ''But the idea that we can take fossil fuels out of the mix very quickly is unrealistic. We're reliant on fossil fuels, and a good pathway is to find ways to use them that don't create a problem for the climate.''

Carbon capture has the potential to reduce more than 90 percent of an individual plant's carbon emissions, said Lynn Orr, director of GCEP and professor of energy resources engineering. Stationary facilities that burn fossil fuels-such as power plants or cement factories-would be candidates for the technology, he said.

Capturing carbon dioxide from small, mobile sources, such as cars, would be more difficult, Orr said. But with power plants comprising 40 percent of the world's fossil fuel-derived carbon emissions, he added, the potential for reductions is significant.

Not only can a lot of carbon dioxide be captured, but the Earth's capacity to store it is also vast, he added.

Estimates of worldwide storage capacity range from 2 trillion to 10 trillion tons of carbon dioxide, according to the Intergovernmental Panel on Climate Change (IPCC) in its report on carbon capture and storage. Global emissions in 2004 totaled
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Source:Stanford University