The Pitfalls and Promise of Geothermal

By Jonathan Marshall

My Google search turned up 70 million hits for “solar power” versus 4 million for “geothermal power.” Yet geothermal plants generated about 13 times more electricity than solar last year in the United States. Geothermal can operate 24/7, unlike solar, and is much less expensive to boot.

GE inverter at ATS

With nearly two dozen power plants in Sonoma and Lake counties, The Geysers is the world's largest geothermal field. (Photo courtesy of Calpine Corp.)

So why does geothermal get so little respect? One reason is that it remains, for now, limited to specific geological formations like The Geysers in Northern California. You can’t generate electricity in your backyard from geothermal, as you can from solar.

The other is that geothermal has been running into a great many obstacles of late. Utah-based Raser Technologies filed for bankruptcy in April “after burning through hundreds of millions of investor financing and a $33 million Treasury Department grant,” noted a recent USA Today story. Also shaky, according to the story, are two other geothermal developers that received government loan guarantees totaling nearly $200 million.

The harsh reality is that deep rock drilling is unpredictable in most respects but one: You can count on it being very expensive. Exploration drilling at a site typically costs $5 million to $10 million. In a time of scarce financing, those risks make geothermal a sometimes unpopular bet.

But the industry’s prospects, both near- and long-term, might be better than these recent stumbles suggest.

The Geothermal Energy Association’s executive director reported a few months ago that the industry “remains on track to add 700 megawatts (MW) of capacity by 2013,” a decent amount.

Aiding developers achieve profitable wells is a remarkable new geothermal map of the United States compiled by Southern Methodist University’s geothermal lab, with a grant from Google.org. It shows details of temperature and heat flows at various depths at 30,000 points across the country. It will eventually be incorporated into a DOE-supported National Geothermal Data System.

And new technology for exploiting hot underground rocks in areas previously unsuitable for geothermal production could boost the U.S. industry’s capacity to 100 gigawatts of power by 2050, according to Ernest Majer, a geophysicist at Lawrence Berkeley National Laboratory. That’s equal to the capacity of about 100 nuclear reactors.

Also bullish is the International Energy Agency, which this summer reported that the industry could increase its contribution to global heat and electricity production tenfold by 2050.

In Japan, researchers last year concluded that geothermal could contribute up to 10 percent of the country’s electricity by 2050, admittedly under ideal circumstances.

And a team of scientists from the Geological Survey of Canada reported recently that the country has vast untapped geothermal potential. “As few as 100 projects could meet Canada’s energy needs,” they concluded. Currently the country has no geothermal plants in operation.

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