How Sologen’s plan to turn abandoned oil and gas wells into geothermal power producers could replace coal power in Texas.
Published: August 10, 2011
If he’s trying to sell me on the solar side of his business, he’s doing a terrible job. “The problem with renewables, A-to-Z, is that they don’t work without subsidies and incentives,” he says. “And solar’s the worst,”
Yet, as long as the incentives are in place it’s a no-brainer. Smith says he recently installed a $200,000 system that ended up costing his client a mere $6,000 once all the federal, state, and local incentives and rebates were applied. The system today produces an average of $4,800 in energy every year. Talk about payback.
But it’s the heat of the earth — specifically a form of geothermal found across the Gulf Coast from Texas to Florida, geopressure — that has him most excited. Geopressure resources are typically found in deep salty aquifers trapped under enormous pressure. Either the steam or the heat of the water is used to drive turbine generators and create electricity. Smith plans to co-generate electricity at his site by also separating and using the methane found in the water.
And his project is worth watching, if for no other reason than because it’s been done before. None other than the U.S. Department of Energy tested a similar well in Brazoria County in the 1980s (Smith is close, but won’t say how close, to that original site) when the agency showed unequivocally that the heat of the earth from geopressure could be converted into electricity. In that investigation, part of a larger DOE campaign begun in the 1970s fueled by national interest in reducing dependence on Middle East oil, operators generated a single megawatt of electricity over six months from both the super-heated water and the natural gas captured and separated from the water. While the electricity couldn’t compete with coal at the time in terms of cost, the project also showed that geopressure could serve as a sustained energy resource: The well was flow-tested over five years, according to Maria Richards, researcher and lab coordinator at Southern Methodist University’s Geothermal Laboratory, without any significant reduction in flow. “They were able to prove that it is a lasting source,” she said.
In the years since the DOE project, called Pleasant Bayou #2, two things have happened that suggest geothermal may be ready for commercialization in Texas. First, the technology has advanced to the point that even lower-temperature waters in the 100- to 300-degree range (which is most of the state’s geothermal capacity) can be effectively used. Second, researchers have mapped out geothermal’s presence across the state, taking much of the guesswork out of the process of deciding where to drill or which wells to re-enter.
While solitary geothermal wells tend to generate a relatively small amount of power, Richards envisions geothermal wells taking over abandoned oil and gas fields the way a field of wind turbines covers a landscape, collectively producing a traditional power plant’s load of continuous energy. In that way, she sees the technology displacing coal plants in the decades ahead. “That’s the neat thing about geothermal: It is baseload. It can be something that can be scaled up. It can really compete with a coal plant,” Richards said.
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