New Life for Power Plants Losing Steam

For decades, energy companies have tapped steam from deep in the earth to make electricity. Now at least five American power producers are testing a simple idea that could dramatically expand the industry’s reach: Bring your own water. Instead of producing power only in places where steam flows naturally, these companies are drilling deeper to inject water into superhot, dry rocks to create the vapor needed to generate electricity. The technology “offers the opportunity of creating additional reserves,” says Mark Walters, a geologist at Calpine, the biggest U.S. geothermal power producer. “The heat is a resource in areas around existing plants, but right now we really can’t get at” it.

If successful, the technology could be used in hundreds of locations worldwide. In the U.S., such plants could supply 100 gigawatts of power by 2050, says Ernest L. Majer, an energy geophysicist at Lawrence Berkeley National Laboratory. That would boost geothermal’s share of the country’s power supply to 10 percent, from less than 1 percent today. “There’s a lot of hot rock out there,” Majer says.