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This story was originally published by Colorado Public Radio. Sign up for CPR’s weekly climate newsletter.
Last spring, Occidental Petroleum, an oil and gas company better known as Oxy, began drilling a massive hole in the shadow of a natural gas processing plant south of Greeley.
Drilling rigs are a common sight in Weld County, an area known for producing the vast majority of oil and gas extracted in Colorado. In this case, however, Oxy erected the tower for a different purpose: not to mine fossil fuels, but to tap carbon-free heat roughly 20,000 feet beneath the Earth’s surface.
The project, known as the Geothermal Limitless Approach to Drilling Efficiencies (GLADE), was supported by a $9 million grant issued by the U.S. Department of Energy in 2022. Its goal was to test whether new drilling techniques could reduce the cost and time required to drill superdeep geothermal wells, a potential global clean-energy game-changer.
Oxy has yet to detail its progress publicly and has declined multiple interview requests from CPR News. Its reports to state regulators, however, show that the company completed its drilling work nearly a year ago, working far faster than traditional superdeep drilling projects. The company started drilling in April 2025, digging twin boreholes almost four miles below the surface over less than six weeks, according to state permitting documents unsealed last month.
In a written statement, Jennifer Brice, an Oxy spokesperson, said the project set “new drilling milestones” for Colorado, and the company is now working to assess the experimental project with its academic and government partners.
The results could reveal whether similar projects — or the GLADE project itself — could support a new generation of geothermal power plants. Estimates suggest the bottom of the wells might exceed 450 degrees Fahrenheit. In concept, Oxy could link the bottom of the boreholes, either with additional drilling or by fracking open the surrounding rock. The resulting loop could heat water or another fluid to generate electricity at the surface.
For more than a century, geothermal power plants have been confined to areas with hot springs or volcanic activity, like Iceland or California’s Geysers region. With the GLADE project, Oxy may have demonstrated that fossil fuel companies are well positioned to overcome those limitations. By cutting the cost of reaching high temperatures far below the Earth’s surface, far more communities could harness 24/7, climate-friendly energy available almost anywhere.
“It’s very promising to see an oil company actually jump in with a drill bit instead of standing around thinking about it,” said Roland Horne, a professor of earth sciences and the director of the Stanford Geothermal Program at Stanford University.
Geothermal has long been the sleeping giant of renewable energy.
The resource currently meets less than 1% of global electricity demand, but humanity has only scratched the surface of its potential, according to a recent report from the International Energy Agency. Far more places can now consider geothermal energy due to recent breakthroughs in drilling and hydraulic fracturing developed by the oil and gas industry.
By using the same techniques to tap underground heat, the report estimates that geothermal could meet global electricity demand 140 times over. Unlike wind and solar, geothermal power plants could also fit into compact footprints and supply steady electricity, no matter the weather.
The main constraint is a basic fact about the Earth’s crust: The deeper you dig, the hotter it gets. With wells less than two kilometers deep, the analysis found that only a handful of countries could reach high enough temperatures to make electricity. At seven kilometers, geothermal could be possible in almost any area of the world.
Reaching those depths is difficult but not impossible. During the Cold War, Soviet geologists spent almost 20 years digging the Kola Superdeep Borehole more than 12 kilometers, or 7.5 miles, deep to study the Earth’s crust, setting the record for the world’s deepest hole. In Colorado, a 22,000-foot-deep oil and gas well in Moffat County holds the statewide record, according to a spokesperson for the state Energy and Carbon Management Commission.
Pressure and heat at those depths wreak havoc on mechanical equipment. With the GLADE project, Oxy set out to prove it could overcome those challenges by working faster and more cost-effectively than past superdeep drilling efforts.
The company itself hasn’t released any results, but state records show it dug one of its two wells in 18 days. Horne, the Stanford geothermal expert, said that pace would put Oxy in league with Fervo, a leading geothermal startup that drilled a nearly 16,000-foot-deep geothermal well in southwest Utah in 16 days last year. “That’s pretty impressive,” Horne said.
Other experts have characterized the effort as a success. Amanda Kolker, the manager of the geothermal laboratory program at the National Lab of the Rockies in Golden, said the GLADE project proved it’s possible to dig deep into sedimentary basins, large-scale depressions more commonly explored for oil and gas resources. The Denver-Julesburg Basin is one of many sedimentary basins in the western U.S.
“This achievement could unlock new geographies for geothermal technology deployment in the United States,” Kolker said.
One question is whether Oxy has plans beyond research for its geothermal boreholes. By completing the GLADE project, the company may have taken one of the most difficult steps toward building Colorado’s first geothermal power plant.
Multiple studies show that Colorado has ample underground heat to support a power plant, but no commercial enterprise has built one so far. In central Colorado, a pair of entrepreneurs has spent decades trying to build a geothermal power plant near Buena Vista. Their attempts, however, repeatedly ran into pushback from local residents worried about noise and disturbing the area’s famous natural hot springs. In August 2025, the state land board threw cold water on the idea by declining to renew a key land lease for a potential power plant site.
The Weld County site is rural and surrounded by oil and gas sites, far from hot springs or towns opposed to industrial development. Such a facility would also align with goals outlined by Gov. Jared Polis. Since taking office, the governor has created new geothermal subsidies and streamlined the permitting process for future geothermal projects, including power plants.
It’s unclear whether the company has any intention of building a power plant, but federal scientists advising the project have at least considered the possibility. A 20-page analysis published by the National Lab of the Rockies in 2024 estimates the GLADE project could produce 2.2 megawatts of electricity, enough to power a small community or industrial site.
In 2024, before drilling began, the company also sent a notice to residents, explaining it planned to link the bottom of the wells and circulate water to measure thermal energy. Depending on those results, the document notes, the company hoped to “design a small test plant to generate electricity.”
Brice, the Oxy spokesperson, said the document refers to a “test plant rather than a power plant,” but didn’t explain the difference. She also declined to answer whether Oxy has already built an experimental power plant at the site or plans to in the near future. “No decisions have been made,” Brice said.
If Oxy pursues a power plant, it could hint at a new investment opportunity for Colorado’s oil and gas industry, said Michael Rigby, an energy transition facilitator with the Colorado Energy and Carbon Management Commission. He suspects that oil and gas firms are waiting for a signal — evidence that the same supply chains and workers behind fossil fuels could pivot to geothermal projects.
“There are synergies between oil and gas and geothermal,” Rigby said. “As we see more things happen, I think we will see more merging in that space.”
A correction was made on March 5, 2026: This story originally misstated Roland Horne’s first name as Ronald.
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