Can Geothermal Energy Pick Up Real Steam?

David LaGesse
For National Geographic News

Steam rising from a valley just north of San Francisco reminded early explorers of the gates of hell. Others saw the potential healing powers of the naturally heated water, and still others realized the steam could drive turbines to generate electricity.

It's been 50 years since power plants began running off the pools of steam that sit under California's Mayacamas Mountains. The pioneering plants in the area known as The Geysers highlighted the promise of geothermal energy, internal heat from the Earth with vastly greater energy potential than that of fossil fuels. But geothermal, virtually free of carbon emissions and more reliable than intermittent wind and solar energy, still provides only a small slice of the world's energy.

Now amid the rush to alternative energies, geothermal advocates sense a new chance to mine the heat rising from Earth's white-hot core. They plan to generate man-made steam by pumping water deep underground into hot, dry rocks in what's called enhanced or engineered geothermal systems. They also despair that governments and businesses aren't investing enough in the sophisticated technology needed to unlock the deep-seated energy.

"There's a window of opportunity where geothermal can play a part in our energy future, and we risk missing it," says David Blackwell, a geophysicist at Southern Methodist University.

Blackwell contributed to a broad study released in 2007 that predicted geothermal could provide one tenth of U.S. power by 2050. But that progress depends on new technology that can move geothermal beyond naturally occurring steam deposits. These enhanced geothermal systems would use tricks learned from oil and gas drilling. They would fracture rock with high-powered streams of water, generating steam to power turbines running above ground.

"That's really the holy grail of geothermal: that you can go anywhere and extract the Earth's heat," Blackwell says.

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