Scientists at the Utah Geological Survey say they have found a massive new source of potential geothermal power in Utah’s west desert.
It is a different type of resource, they say, much deeper than the geothermal industry now uses. But it still should be exploitable.
Over the past two years, crews drilled nine wells in Utah’s Black Rock Desert basin south of Delta to test out a theory that water at high temperatures might exist deep beneath the surface that would be hot enough to be turned into steam, which could then be used to generate electricity.
They hit pay dirt.
“There is definitely something there, and it is big,” said Rick Allis, director of the Utah Geological Survey.
The agency has identified an approximately 100-square-mile area within the Black Rock Desert basin it believes could eventually support power plants that could conservatively produce hundreds of megawatts of electricity. A megawatt is enough energy to run the appliances in 750 homes.
Allis said the area is especially attractive for geothermal development because of the existing infrastructure. There is a large coal-fired power plant in the area, a 300-megawatt wind farm and a major electrical transmission line nearby that could be used to get the power to where it is needed.
“Our next step is to get [the geothermal power industry] interested in moving forward to develop this resource,” he said.
The Utah Geological Survey plans to tell the industry about its discovery at the annual meeting of the Geothermal Resources Council next week in Reno.
Karl Gawell is president of the Geothermal Energy Association, which is part of the council. On Thursday he termed the Utah discovery “exciting” and predicted it would be generating a lot of talk and interest among companies that are developing geothermal resources. “It’s exciting for Utah, too, because it could eventually generate a lot of jobs and economic growth.”
In one sense, though, the Utah discovery wasn’t unexpected.
The U.S. Geological Survey several years ago conducted a survey of the nation’s available geothermal resources. At that time it estimated 80 percent of the potential sites had yet to be discovered.
“We’re still in the exploration stage when it comes to finding new resources,” Gawell said. “So this discovery just confirms what everyone in the industry already knows, that there is a lot of undiscovered potential out there.”
Although environmentalists generally look upon geothermal projects as being worthwhile developments, Christopher Thomas of the Healthy Environmental Alliance of Utah (HEAL) said every undertaking needs to be thoroughly reviewed to make sure there are no adverse impacts.
“You have to ensure that there is smart site selection, and that the development follows all the rules,” he said.
Still, Thomas pointed out that Utah is seventh out of eight Western states when it comes to renewable energy production. “If we want to ensure continued economic prosperity . . . we’ve got to be looking at geothermal, wind and solar energy.”
One potential drawback to the Utah site is the depth of the formation. Any company that wants to develop a power plant in the Black Rock Desert will have to bring water up from deep underground — as much as 10,000 feet — use it to generate electricity then inject it back underground for reheating.
Yet neither Allis nor Gawell see that as an obstacle that can’t be overcome.
“It is deeper than the geothermal industry is used to, but it isn’t unusual for the oil and gas industry to operate at those depths,” Allis said.
Preliminary economic modeling suggests that a large geothermal plant could produce electricity for about 10 cents per kilowatt hour, Allis said. Although that cost is higher than the roughly 8 cents per kilowatt hour Utahns pay for their electricity it is well below the going rate of around 15 cents that consumers in California pay.
“The power could be sold in California at a profit,” he suggested.
Utah Geological Survey geologist Bob Blackett in Cedar City was the first to realize that something was going on deep underground in the Black Rock Desert.
Four years ago, Blackett was looking at “bottom-hole temperatures” of oil wells that had been drilled in the state. One stood out. It was a well that had been drilled in the basin and abandoned by Arco in 1981. The oil company had reported a bottom-hole temperature of 450 degrees — far hotter than the average of around 250 degrees that is common in Utah’s western reaches.
“It really stood out,” Blackett said. “I mentioned it to Rick (Allis) and he ran with it.”
Allis explained that most geothermal exploration in Utah and Nevada has traditionally focused on narrow zones along the faults of mountain ranges where hot water bubbles to the surface.
The discovery in the Black Rock Desert represents a new type of resource the could increase the potential for geothermal development throughout the West, he said.
“There are other potentially hot basins across [Utah and Nevada] that need to be investigated. “We have identified the Steptoe Valley and Mary’s River-Toano basins in northeast Nevada as obvious geothermal targets.”