THE VINE AUGUST 20, 2009
On paper, at least, "enhanced" geothermal is an incredibly alluring concept. The idea is to bore down, really deep down into the Earth's crust—say, 12,000 feet below the surface—and then pump water through the cracks in the hot bedrock, creating steam to generate electricity. Last year, an MIT report on "The Future of Geothermal Energy" calculated that, if you could make this technology work, the capacity would be staggering: For a mere $1 billion invested over 40 years—the cost of a single large coal-fired plant—we could get 100 gigawatts of carbon-free power, the equivalent of more than 200 coal-fired plants.
So what's the hold-up? Turns out it's not such a snap to grind that deep into bedrock. As James Glanz reports today in The New York Times, one pilot project, financed by the Energy Department and located at the Geysers north of San Francisco, has been bumping up against serious obstacles. Like cap rock. Not only does the drill bit keep fouling up (or even, on occasion, snapping), but there are newfound fears that the drilling could generate earthquakes, which is what happened at a test site in Basel, Switzerland:
The fracturing would be virtually guaranteed to induce earthquakes, which the company has said would be so small as to be nearly imperceptible but which local residents and some scientists fear could be larger. The project is in one of the world’s most seismically active areas.
Although the Basel earthquakes caused only minor structural damage, they frightened many in the city and led to the shutdown of the project there. The Energy Department review, likely to be released in the next few weeks, is expected to compare the Basel and California projects and determine whether AltaRock’s effort is safe.
Much sniping ensues, in which the company doing the drilling, AltaRock, claims that the Swiss were stupidly drilling near a known fault line, and the Swiss accusing the company of lying. If you like earthquake intrigue, read the rest. Though it'd be a real shame if this project had to shut down, seeing as how enhanced geothermal's clean-energy potential is so enormous.