Scientists have spent years fracking outside Milford, jamming chemicals and water into the earth to break rock with the same technique that’s drawn controversy to the oil and gas industry.
In April, they tested whether water would flow through the hot granite they had fractured — and if enough gallons would return to the surface, heated enough by the warmth of the earth, to create steam power.
For eight hours, they didn’t see anything happening.
Then a boiling wave surged across their monitors — proving that clean energy from the earth can work on a commercial scale.
“This is a group that doesn’t do too many high fives,” said researcher John McLennan, laughing, “but it was a huge relief and feeling of satisfaction for everybody.”
What it showed, he explained, is that geothermal power collected this way “is a feasible form of energy. It really bodes well for a renewable energy that is 24/7.”
The Utah Frontier Observatory for Research in Geothermal Energy, an underground field laboratory sponsored by the U.S. Department of Energy in Beaver County, is the largest geothermal energy experiment in the nation. The site announced the results of its April experiment on May 23.
Think of volcanoes and the geysers at Yellowstone National Park as examples of geothermal energy. Capturing the heat within the earth in the form of steam can produce renewable energy.
Traditional geothermal power plants tap into underground reservoirs with three features: heat, water and permeability. The plants direct water down one well, where the earth’s heat warms it as it travels through cracks in hot rock toward another well. Next, they draw the heated water back to the surface. The steam from the heated water can spin a turbine, which in turn activates a generator to produce electricity.
It’s rare to find underground reservoirs with all three of those features in place. Utah FORGE aims to change that by creating human-made geothermal reservoirs.
“We are thrilled to see these remarkable achievements at FORGE, and the promise this geothermal breakthrough holds for our clean energy future,” said Jeff Marootian, principal deputy assistant secretary for the DOE’s Office of Energy Efficiency and Renewable Energy.
(Rick Egan | The Salt Lake Tribune) The drill site for Utah FORGE, the nation's largest geothermal experiment, north of the town of Milford, on Thursday, July 6, 2023.
“The ability to tap more of the Earth’s natural heat through enhanced geothermal systems will expand access to affordable, secure and resilient clean energy for everyone, " he said.
This recent experiment builds on progress made last summer when FORGE scientists succeeded in pushing water through the deep fissures they’d created by fracking. While they were able to inject water underground and watch it return to the surface, that experiment didn’t produce enough heated water to prove commercial viability.
The Utah FORGE site is a premier location for this type of geothermal energy extraction, McLennan said, because of its temperature, depth and low frequency of earthquakes. Researchers there don’t have to drill too deep to find adequately hot rock for geothermal energy production and the area is, in McLennan’s words, “relatively seismically benign.”
Injecting water into the ground at a high pressure to create fractures or widen existing ones can activate a fault zone and increase the risk of earthquakes. Utah FORGE reported that its latest experiment caused seismicity at 1.9 on the Richter scale; for reference, the U.S. Geological Survey reports that most people can feel earthquakes that register above 3.0.
All but 30% of the water injected into the ground during the April experiment — nearly 5 million gallons total — came back up through the production well. The impotable water used in the experiment came from a well drilled on the site. Under commercial conditions, that water would be injected back into the earth and pumped up again to generate more energy.
The next step in realizing clean energy from the earth will be another experiment at FORGE in July. This test will run for 30 days to evaluate the pressure at which researchers should inject water to create circulation for a longer period of time, and to determine produced water temperatures over that time frame.
The U.S. Department of Energy in a 2024 report claimed that the geothermal power industry will reach full commercial scale by 2050. The U.S. generates more geothermal electricity than anywhere else in the world. However, as reported by the U.S. Energy Information Administration, geothermal energy accounted for just 0.4% of the country’s electricity generation in 2022.