What if there were an inexhaustible source of clean power right below us?

In a sense, there is. Many of the oil wells that freckle the Texas landscape endure tremendous amounts of heat and pressure trapped within the earth’s crust. Buried seas of natural-gas infused water at their depths can squirt to the surface with more than enough force to generate electricity. In the 1990s, Mississippi inventor Robert Hunt tried to yoke that power using traditional turbines, only to watch sand and well debris shred them within hours.

But a new technology he’ll soon test on a well near Houston just might turn his idea into a boon for renewable energy development in Texas.

“I believe, at the end of the day, that geothermal will be the top renewable because of its 24/7-nature — it’s there all the time,” Hunt said in an interview.

Even as wind and solar become cheaper, their intermittent nature makes them tricky for cranking out the quantities of consistent baseload power that utilities generate at large coal, gas and nuclear plants. Traditional geothermal generation, which relies on naturally occurring pockets of steam, hasn’t changed much in the United States since the 1960s. And Hunt believes deep subterranean heat can offer an energy source that is not only consistent but also profitable at today’s electricity prices.

Here’s how: A good number of Texas’ 600,000 oil and gas wells tap deposits under enough pressure to shoot water to the surface. Instead of the delicate blades of a turbine, Hunt wants to feed that liquid into a sturdy set of pistons that milk the potential gusher for mechanical energy that a generator can turn into electricity. Another system would extract natural gas trapped in the liquid, and there’s also potential to generate additional power from the water’s heat.

The product Hunt envisions isn’t much bigger than an air conditioning unit, and all the water pulled out of the ground gets put back in. Even without re-injection, the fluid in question lies thousands of feet below the groundwater used for drinking, in reservoirs that would take decades to deplete. The systems are projected to cost roughly $1.5 million each, and in an optimal situation, Hunt said revenues would be split about evenly between gas and electricity sales.

One well has the potential to generate two to five megawatts of electricity. To put that in perspective, there are 7,641 wells in Harris County, according to OGI. If 450 of them could generate three megawatts apiece, they’d produce more power than the proposed White Stallion coal plant in Matagorda County.

Like any potentially game-changing technology, the oil-well-as-power-plant concept can elicit as much skepticism as it does hope.

Will its concepts be brought to scale? Or will the project face the uncertain end of other promising energy concepts like the Superphenix breeder reactor or Beacon Power’s vacuum-sealed flywheels? Hunt, Texas A&M at Galveston oceanographer William Merrell and investors with a company in Galveston are willing to find out.

At present they’re conducting lab research, developing a unit they hope to attach to a well site they’ve located in the Houston area next year. If all goes to plan, a commercial product will come to market in late 2012 or 2013.

So far, Hunt says, the research is going well: “We’re knocking on the door, and I think we’re close.”

With a glut of retired wells already reaching from the Texas soil into the hot depths of the earth’s crust, it’s certainly worth a shot.

In the video at the top of the story, watch Robert Hunt explain the concept at a Tedx Talk in Austin.