This article was first published by The Texas Tribune, a nonprofit, nonpartisan media organization that informs Texans—and engages with them—about public policy, politics, government and statewide issues.
STARR COUNTY—In 2009, on a plot of shrub-covered cattle land about 45 miles northwest of McAllen, Shell buried and abandoned a well it drilled to look for gas. The well turned out to be a dry hole. Vegetation grew back over the site.
In 2021, a Houston-based energy company run by former Shell employees came looking for it.
This company wasn’t drilling for oil or gas, though. Its engineers were looking for a place to experiment with their technology for producing geothermal energy, created by Earth’s underground heat.
A startup called Sage Geosystems leased the site. The company installed a wellhead and brought in a diesel-powered pump. They used fluid to create cracks in the rock deep below the surface, a technique similar to fracking for oil and gas.
One day last March, the crew pumped 20,000 barrels of water into the 2-mile-deep well. Hours later, an operator opened the well from a control room. Pipes above ground shook as the pressurized water gushed back up. The water spun small turbines, generating electricity.
Sage and other companies believe geothermal power is key to replacing polluting coal- and gas-fired power plants. Even though solar and wind are proven clean energy sources, they only produce electricity when the sun shines or the wind blows. Geothermal power could provide continuous, emissions-free energy.
“Geothermal heat doesn’t have those variable conditions,” University of Texas at Austin clean energy expert Michael Webber said. “If you hit a hot spot below ground—might be thousands of feet down—the heat won’t matter based on whether it’s cloudy or whether it’s summer.”
Texas has become an early hot spot for geothermal energy exploration. At least three companies are based in Houston, and scores of former oil industry workers and executives are taking their knowledge of geology, drilling and extraction to a new energy source.
“We’ve punched over a million holes in the ground in Texas since Spindletop,” said former Texas oil and gas regulator Barry Smitherman, who has become a geothermal advocate. “So we have a lot of knowledge, and we have a lot of history and skill set.”
Heat constantly radiates out from the center of Earth as radioactive elements break down. That energy warms water that bubbles up to or escapes as steam at the surface. Humans have taken advantage of that phenomenon—an early form of geothermal power—for heating, bathing and cooking since ancient times.
For more than 100 years, engineers have used that underground hot water or steam to generate electricity. Geothermal power in 2015 fueled 27% of the electricity in Iceland, which sits on one of the world’s most active volcanic zones. In 2022, it generated about 5% of the electricity in California. The United States is the top geothermal electricity producer in the world.
Still, the total amount of geothermal electricity produced in America is tiny compared with other sources. It accounted for about 4 gigawatts last year, according to a federal analysis, or enough to power about 800,000 Texas homes.
Businesses such as Sage and government researchers say there’s a lot more geothermal power to be had by pumping fluid through hot rock where there is no natural water. With technological advances, a government analysis predicts geothermal power in the U.S. could grow to 90 gigawatts by 2050. That would have been enough to power the entire Texas grid during last summer’s highest-demand day.
Companies are racing to develop their technology and techniques to harness this energy source. They vary in how deep they want to drill (from around 7,000 feet, which oil and gas equipment can handle, to 66,000 feet, which it cannot), how they heat the water (in the well or in the rock) and how they bring the heated water back up (in the same well that sent it down or with a second one).
Like oil wildcatters, the geothermal industry must figure out the best places to drill. They’ll face the…
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