An opinion in the journal Nature says it’s time for some straight talk on the dangers of geothermal energy.
The risks may be small, but a technique called an enhanced geothermal system (EGS) has the potential to cause damaging earthquakes. Here in Oregon, Davenport Energy has proposed using an EGS technique to look for geothermal energy next to Newberry Crater. More on that later.
The warning comes from a supporter of geothermal energy who says he’s not trying to be an alarmist. Rather he says, he wants to avoid a backlash against EGS because of its amazing potential to supply clean energy just about anywhere.
The Navy 1 geothermal power plant near Coso Hot Springs, California, is applying EGS technology. Photo from Department of Energy.
Traditional geothermal techniques use hot water produced by earth for heating and generating electricity. A classic example are the hot springs that dot Oregon’s countryside. Near Newberry, when Davenport power went looking for geothermal energy they didn’t find much hot water, but they did find hot rocks. That’s the kind of situation EGS is designed to exploit. Water is pumped down the well to be heated by the rocks, then withdrawn as an energy source.
The process fractures the hot rocks beneath the surface, making it easier to circulate the water. But the fracturing also causes small earthquakes that can be felt by people on the surface. In rare cases, the quakes are big enough to cause damage.
Writing in tomorrow’s issue of Nature, Domenico Giardini of the Swiss Seismological Service, uses a case study from Basel, Switzerland as an example of what can go wrong. In December of 2006, the area was rattled by thousands of micro-quakes when water was pumped down a geothermal well for the first time.
The seismic activity was strong enough to convince officials to stop pumping water the next day. But it wasn’t soon enough. Later that day, a magnitude 3.4 quake shook the area, spreading fear and anger among the public. Since then, insurance payouts on the damage have totaled more than $9 million. Giardini notes that many of the claims were for non-structural problems such as cracks in plaster.
The lesson here, according to Giardini, is that “the public reacts with a vengeance if it perceives that a known problem has been hidden.” He goes on to say, “The risk of overreaction (to EGS projects) is very real. The establishment of an overly harsh regulatory framework would penalize the geothermal industry in comparison to other energy sectors.”
How much potential is there in EGS? Giardini cites a 2006 study produced at MIT that concluded EGS could provide 100,000 megawatts in the United States by 2050. That’s about 10% of current electrical production. The federal government has committed more than $132 million to EGS demonstration projects around the country.
If you drill deep enough, you should be able to find hot rock just about anywhere, including areas where lots of people live. Deep EGS projects could potentially be located in cities. But also raises the risks, no matter how small they may be.
Giardini says these risks have to be discussed openly by officials with the public. He says its important to figure out ahead of time how payment for damages will be handled and how much risk is acceptable to the public. “Otherwise,” he writes, “society risks a public backlash that could unnecessarity quash a promising alternative-energy technology.”
Giardini’s Opinion Piece will be published in the December 17 issue of Nature.
For more on the geothermal exploration near Newberry Crater, see the recent article on the Bend Bulletin, Geothermal drilling might SHAKE Newberry.
