What’s the real scoop on Geothermal and earthquakes? Despite a NY Times report that has been picked up by other outlets, (for instance, here and here), the Department of Energy (DOE) is not initiating any major new regulations for Geothermal projects.
What they have done: building on the experience at The Geysers geothermal field in California, they are issuing a new policy that will apply to “all new Enhanced Geothermal [Systems (EGS)] projects, including those recently funded through the Recovery Act.” The Obama Administration is providing $338 million in funding to a total of 123 projects, although there are no figures on how many of those involve EGS, which generally fractures rock deep in the Earth to allow water to more easily flow through, collecting heat that can then be used to generate power. Mico-quakes cansometimes be produced by slippage along those fractures.
(Image: AltaRock Energy)
According to a DOE letter to the office of Congressman Henry Waxman (D-CA) obtained by TENTHMIL, the policy will feature:
• The Department will require grantees to collect stress data, background seismicity, and geology data prior to actual field stimulation. Once the data are collected, the grantee will use predictive stimulation models to estimate and forecast potential induced seismicity magnitude and potential radius of seismicity. Information submitted by grantees will be used to develop site specific risk mitigation strategies.
• The Department will task a team of experts to review these results as a part of a go/no-go decision point.
• If judged satisfactory, grantees will be given the go-ahead to conduct field work with adequate permits from local authorities. Otherwise, they will be asked to gather more data and conduct more analysis.
This comes on the heels of two projects – The Geysers, in California, run by Seattle-based AltaRock Energy, and a project in Basel, Switzerland. Both of them were in populated areas near seismic zones – and both were recently shut down after jolting local residents. In both cases, the companies were experimenting with EGS technique.
(Image Source DOE, AltaRock Energy)
Scary Words
The NY Times story opened with, “The United States Energy Department, concerned about earthquake risk, will impose new safeguards on geothermal energy projects that drill deep into the Earth’s crust.” Some picked up the drumbeat and inserted the words “new regulations.” But the DOE isn’t taking things quite that far.
Ernest Majer, a geothermal expert and deputy director of the Earth Science Division at Lawrence Berkeley National Laboratory in California, told TENTHMIL, “We’re in the process of reevaluating what sort of mitigation controls will be put on. They’re not regulations, and we don’t want to put regulations where they’re not necessary.”
On the other hand, he said, the experience that AltaRock had drilling at The Geysers has taught everyone some important lessons, and they wanted to bring that to the table. And they mostly appear to involve the application of common sense when you’re doing seismically sensitive drilling and fracturing in an area with a lot of buildings.
That’s what caused trouble for the Basel project – it was in the middle of town, where even the smallest jolts will shake people up and potentially leave cracks in buildings. There were fewer people living around The Geysers, but they weren’t any happier about the temblors – or about the way their concerns were dismissed.
“It’s ironic,” notes Majer, “because AltaRock’s drilling never even made it below the caprock. They went into an existing well and got jammed up, which was probably their problem – in old wells things can shift.” They never even got as far as fracturing the rock down in the geothermally-interesting heat zone.
But what happened was a public-relations problem. Because they’re experimenting with a new, proprietary process, Majer says the company couldn’t be forthcoming in describing what they were doing, and people got suspicious.
“They’ve got another project at Newberry, Oregon” that they’re moving forward with, he adds. Not only is that site far from people, the ring-fracture system of the Newberry Volcano will limit the dispersal of any potential stresses.
“That seems like a more attractive prospect for experimenting right now,” so they wrapped things up at The Geysers, even as the DOE was finding that the quakes there, while disconcerting, wouldn’t have had an impact on the local population.
(Originally appeared at TenthMil.com)
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