AltaRock Energy, a California-based company specializing in engineered geothermal systems (EGS), was the subject of a story in today's New York Times which was certainly alarmist, if not genuinely alarming. AltaRock is currently preparing to put into action a design for a demo geothermal project in California's NCPA Geysers Geothermal Field area. This area, which has been producing geothermal energy from steam wells since 1983, is located in the seismically shaky San Francisco Bay Area. The same geological factors that make the area a good place for geothermal energy extraction make it a high-risk area for earthquakes, and it is on these fears that the Times article centers.

The article does not have much to say about the particular risks involved with AltaRock's project. Instead, it recounts the story of a 2006 project run by the Swiss company Geothermal Explorers, which aimed to extract geothermal energy from the bedrock near Basel. Geothermal Explorers used a technique that involved shooting a jet of water into drilled holes, which then produced fractures (a technique known, to the delight of Battlestar Galactical fans everywhere, as "fracking") in the hot bedrock below, where the water was heated, rose back to the surface, and upon expansion emerged as steam, which powered turbines to produce usable energy. The result was an always-on source of non-polluting, waste-free energy, which seemed like a good bargain until reports of small earthquakes started coming in. In response to these reports, the project was immediately shut down.

The Times article speculates, in no uncertain terms, that AltaRock's project could well trigger a similar series of small earthquakes in California; it even suggests that a larger earthquake could result from deep drilling. Yet the Swiss drilling project did not produce large earthquakes, and Basel had long been known to be somewhat earthquake-prone. Indeed, the article notes that the small earthquakes "terrif[ied] many in a city that, as every schoolchild here learns, had been devastated exactly 650 years before by a quake that sent two steeples of the Münster Cathedral tumbling into the Rhine." It was not the severity of the existing earthquakes that stopped the project, but the vague possibility that another large earthquake might occur. Rudolf Braun, who chaired a study of the risks of resuming the Basel project, said, "This was my main question to the experts: Can you exclude that there is a major earthquake triggered by this man-made activity? I was quite surprised that all of them said: 'No, we can't. We can't exclude it.'" But for these experts to say that they could not absolutely exclude the possibility that a larger earthquake might result is quite a different thing than for them to say that they thought it would happen, or even that it was at all likely to happen. The mechanisms of seismic activity are still poorly understood, particularly the relationship between small and large earthquakes in a given area; seismologists do not know for certain if small earthquakes make large ones more or less likely.

Add to this the fact that AltaRock's technology is not the same as that of Geothermal Explorers. The approach is roughly similar, but the proposal is more complex than drilling a hole in the ground and waiting for steam to emerge somewhere else. Both companies keep the specifics of their techniques as a proprietary secret, and there is a lot of room for variation. AltaRock's technology is specifically designed to be usable in areas without pre-existing geothermal resources, which is to say in areas of lower seismic activity. Coupled with the variability of the geological environments in Switzerland and the California test site, it seems premature to conjecture that the effects of AltaRock's EGS would be the same as those in Basel.

None of this is to say that there was no error on AltaRock's side. The geothermal researchers who went on to found the company filed a report with the Energy Department about the ramifications of EGS, and that report did not contain any information about the Basel earthquakes, which had occurred about a month before the report was sent to the Energy Department. Even if (as they claimed) the document was already at the printer when the news came out, the researchers should arguably have gone to greater lengths to inform the Energy Department about it. But this is an issue of dubious significance. AltaRock did file a seismic activity report with the Bureau of Land Management, in which the Basel earthquakes were prominently mentioned, but even so not everyone at the Bureau appears to be fully aware of the report's contents. The Times article cites only one engineer from the Bureau, who says he wasn't aware of the events in Basel, but that he would probably have approved the project even if he had. So the issue of disclosure, of which much is made in the article, appears to be a non-starter.

The Times article does the valuable service of bringing a little-known negative externality of EGS into the spotlight. Yet the alarmist attitude of the article, and the ease with which it slides between Switzerland and California, 2006 and 2009, Geothermal Explorers and Altarock, is inappropriate. A series of small earthquakes in a region of Europe which was already a hotbed of seismic activity is not a reason to demand that a different (albeit similar) project here be brought to a halt. The Swiss reaction appears to have been the product of great cautiousness, combined with a heavy dose of NIMBYism. But the promise of geothermal energy is too great to abandon now because of these fears.

Besides, communities throughout the world already put up with earthquakes induced by the extraction of coal and natural gas, including the devastating 2008 Sichuan earthquake in China and the 2007 Crandall Canyon mine disaster in Utah. A proposal to drill for natural gas in more than 50,000 separate locations under the Delaware River Basin using the same kind of technique as the EGS projects is under consideration; these projects add the risks of chemical contamination to the possibility of triggering seismic activity. Royalty money from the gas companies seems to compensate locals for the possibility of earthquakes; AltaRock might consider a similar program if complaints start coming in. (Seriously.)

Every energy source brings its own downsides and dangers. EGS is not a perfect system; even beyond the possible seismic risks, an energy-generation project that relies on large quantities of fresh water has obvious drawbacks, particularly in parched California. These downsides are, paradoxically, the reason we have to tap every energy source, to spread out the negative externalities. (And no, I am not advocating a GOP style "all of the above" approach that somehow uses only fossil fuels. We have already reaped sufficient negative externalities from that energy source; time for some new problems.) The possibility of triggering small earthquakes in California, where we're already pretty good at dealing with small earthquakes, is not a reason to halt the project. Neither is the vague and untested possibility that a larger earthquake might occur. If we sit back and wait for a perfectly cheap, efficient, and safe source of energy, we'll be waiting a long time.