A project that was supposed to show the potential of turning the heat from hot rocks deep in the earth into a clean power source, from a startup backed by Google.org, Kleiner Perkins, Khosla Ventures and the Department of Energy, has hit a snag — literally. Geothermal startup AltaRock Energy said yesterday that it has “encountered a number of physical difficulties,” while drilling at a site in Northern California, or as the New York Times put it, the drilling snagged on surface rock formation. As a result, the $17 million drilling project, which started in June, is being suspended indefinitely, the company says.
It marks the latest setback for AltaRock, the list of which New York Times reporter James Glanz has been chronicling. It ranges from one of AltaRock’s drills not being able to pierce hard rock deep in the earth, to concerns raised over the potential for earthquakes that occurred during a similar style of drilling in Basel, Switzerland. AltaRock has raised $26.25 million from Khosla Ventures, Kleiner Perkins Caufield & Byers, Vulcan Capital and Google.org and won $6.24 million in funds from the Department of Energy.
AltaRock, founded in 2007, has been betting on a more advanced form of geothermal power called “enhanced geothermal,” an approach that doesn’t require existing steam vents or subterranean water sources. Conventional geothermal energy, which has been used for decades, is collected from naturally occurring pockets of underground hot water, which produce steam that can be used to run a turbine. Enhanced geothermal, on the other hand, drills into hot rocks, circulates water through the system and uses the steam to power a traditional turbine (see video, which interviews Steven Chu before he became the Department of Energy Secretary).
AltaRock says it’s looking at several other locations for drilling and that the suspension had to do with “geologic anomalies particular to the formation underlying this well location.” So it’s too early to suggest that this is a setback for the promise of enhanced geothermal. But enhanced geothermal has been widely touted as a major untapped clean power resource, and has yet to prove that potential. Googe’s Dan Reicher has been one of the technology’s most high-profile advocates, and, if you watch, the video, Steven Chu also calls enhanced geothermal exciting because it’s a reliable form of energy with “an unlimited supply.”