Researchers with the University of Texas at Austin say Presidio County’s border region could be a promising site to generate geothermal energy.
The Presidio Municipal Development District put $15,000 toward a preliminary assessment last summer, after a sweeping report on geothermal capacity in Texas highlighted potential in the county.
Local officials hoped the renewable energy source — which generates power from underground heat — could help fuel new industry in the rural border community. After nine months of research, UT geophysicist Ken Wisian, who led the assessment, told the PMDD this week the findings are encouraging.
“Bottom line is, the immediate area in Presidio, but the whole county, looks like a really good development target. As good or better than areas that are already being developed in Texas,” he said.
Heralded as a sustainable power source and a key tool in the fight against climate change, geothermal currently accounts for less than 1% of U.S. energy production. But its popularity is growing in Texas, with at least three companies based in Houston, according to the Texas Tribune.
That’s thanks in part to technology inspired by the oil and gas industry.
Until recently, Wisian said, geothermal development in the U.S. has been focused in the West, limited to places where hot water is accessible through permeable rock. Traditional geothermal systems tap into that water deep in the earth, pumping it to the surface to drive a turbine.
But using a technique similar to hydraulic fracturing, or fracking, it’s now possible to generate geothermal energy in drier places — by injecting water into the ground and heating it with the rock itself before pumping it back up through a well.
That’s what could make Far West Texas’ border region appealing, Wisian said. While the Big Bend is largely devoid of the oil and gas wells that dominate the Permian Basin, just a few hours north, researchers say the area has some of the hottest subsurface rock east of the Rocky Mountains.
Wisian told officials Presidio County as a whole has the conditions necessary for geothermal development: even in the northern parts of the county, he said, you can reach the minimum temperature required to generate electricity at under 5 kilometers below ground. But conditions are best along the Rio Grande just west of Presidio, where it’s possible to reach the same temperature at just 2.5 kilometers.
“Having worked all over the U.S. and parts of the world, that's a pretty attractive temperature depth curve,” he said.
His team argues that an abundance of cheap land and existing infrastructure for international trade could also make the city appealing to developers. And while Presidio’s small population means its energy demand isn’t huge, geothermal could power industries the city hopes to cultivate — from drying chiles brought in from Mexico to cooling greenhouses that could help revitalize local agriculture.
PMDD board members pointed out the potential to export energy across the border — though Wisian said regulations around international power transfers can be complicated.
Discussion at the meeting centered on economics. Geothermal technology isn’t cheap to install: Wisian said drilling an initial well in Presidio would likely cost millions. But he noted that federal credits for renewable energy projects could help cover a significant percentage of those costs. And he told officials that drilling would be the most expensive part of the process.
“Geothermal projects have high upfront costs, and very, very low back-end costs,” he said.
While geothermal is often presented as an alternative to fossil fuels, researchers have argued that it could become attractive to oil and gas companies, thanks to the significant overlap in technology.
It could also generate some of the same risks as fracking — like earthquakes.
Enhanced geothermal systems are still fairly new, but wells in Europe and Asia have generated seismic activity — including a magnitude 5.5 earthquake in Korea. Wisian said his researchers are monitoring a test well drilled in Texas, and they believe the dangers aren’t comparable to those associated with fracking, but he acknowledges the risk.
“I can’t say none,” he said. “You won’t be putting a lot of water in the ground or taking it out, so you don’t have that issue. But over time, you will have thermal contraction.”
The new forms of geothermal drilling are designed to recycle water in a closed system — though Wisian said some leakage can occur.
The audience at Wednesday’s meeting included several local officials who expressed excitement over the study’s findings, including County Judge Joe Portillo, who encouraged local officials to look into possible funding sources.
Marfa resident Trey Gerfers, who directs the county’s groundwater district, brought the initial idea of the geothermal study to the PMDD. He proposed creating a local working group to consider ways to capitalize on the study’s findings.
“Let’s just put our brains together and come up with draft proposals, and then we go to the county and say look, this is what we’ve come up with,” he said.
John T. Kennedy, who was recently hired as an economic development consultant, was also enthusiastic.
“Geothermal is going to be a huge component, going to be one of our major initiatives,” he said.
Wisian told officials he hopes to hold a workshop later this year to discuss possible next steps for geothermal development in Presidio.
