Jeremy Hobson: In the energy business there are renewables like wind and solar. And there are non-renewables -- like oil. Once you use up the oil that's in the well. That's it. Well, actually, a few researchers and entrepreneurs in Texas say that's not it.
Andrew Oxford reports.
Andrew Oxford: In his office at the University of Texas, geologist Bruce Cutright is pouring over maps and charts.
Bruce Cutright: This is just a picture of the number of wells there are in Texas -- existing wells -- somewhere between 1.2 and 1.4 million.
He is trying to show me what oil and gas companies usually don't see when their wells dry up. Those wells, Cutright says, are more than just holes in the ground.
Cutright: As you drill deeper into the Earth, it gets hotter and hotter. By the time you're below 12,000 feet, you're encountering temperatures above 300 degrees Fahrenheit.
All that heat, Cutright says, could be used to create geothermal power. Usually, it's generated by harnessing the heat from hot water near the surface -- geysers, for example. Drilling for that heat has long been considered too expensive. If someone else has already drilled a hole for you, it could be much more affordable. That's where entrepreneurs like Frank Smith come in.
Frank Smith: The oil and gas guys have no interest in water because when they see water they say "uh, my well is done."
But water is just what Smith is looking for. Smith is the CEO of Sologen Systems, a start-up in San Antonio that is repurposing oil and gas wells to generate geothermal energy.
Smith: We're using hot salt water. The water is already heated we just have to bring it up to the surface, extract the heat out of it, and put it back in the ground.
Smith is ready to start producing power. While each well only produces eno ugh energy for a few hundred homes at best, connect several wells on a single acre and it can add up. But, when it is all added up, can geothermal compete with the low cost of fossil fuels?
Uday Turaga: Oil and gas developers are saying, "Why shouldn't I just continue drilling for oil and gas?"
Uday Turaga runs ADI Analytics, an energy consulting firm in Houston. He says a hydrofracturing boom is keeping oil and gas prices low. There is uncertainty around renewable energy incentives and many investors are staying away from geothermal.
Turaga: I would say interest is fairly low so someone has to do it on a commercial scale for the first time.
That is exactly what Sologen aims to do with just a few of the more than one million wells already drilled across Texas.
In San Antonio, I'm Andrew Oxford for Marketplace.