Wednesday, October 23, 2013

A Startup Uses Fracking to Get at Clean Geothermal Power | MIT Technology Review

A Startup Uses Fracking to Get at Clean Geothermal Power | MIT Technology Review:
A geothermal well at the Newberry Volcano in Oregon where new rock fracturing technology was tested.
A startup, AltaRock has figured out a critical piece of puzzle to get more heat out of a geothermal well, but work remains before the energy source can dent carbon emissions.
 It’s long been known that doing the same thing could increase hot water production from a geothermal well. But it’s not possible to use the same techniques used in fracking to plug the well. Geothermal wells are typically hotter, and they need to be engineered for higher amounts of water flow.

AltaRock has essentially invented a new plug. At a well near the Newberry Volcano, it has demonstrated that it’s possible to temporarily plug a geothermal well with a special polymer. The material degrades after it’s been down in the hot rock for a certain amount of time, allowing the company to move on to another part of the well. The company fractured three separate areas of one well using the technique. In a future commercial project, it might do seven or more per well, which “could dramatically lower the cost,” says Susan Petty, the president and chief technology officer at AltaRock. She says the technology could be key to making EGS competitive with coal.

But while the AltaRock technology is a key advance, it’s still early days for geothermal power. “AltaRock’s technology is important, but it’s only one part of the puzzle,” says Jefferson Tester, professor of Sustainable Energy Systems at Cornell University. He says there are several remaining engineering challenges, and solving them will require sustained funding, not just for the project AltaRock is working on, but for several others as well. He says what’s needed is a critical mass of demonstrations to prove to businesses that geothermal power plants are a sound investment. He estimates that it will take decades for geothermal to account for even 10 percent of the total power in the United States.

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