For Texas electricity customers, geothermal energy is pretty much an afterthought. But some scientists — and even some people in the oil and gas business — say that heat from deep underground may become a significant source of power.
At least, that’s the message at a conference held today at Southern Methodist University, hosted by the school’s geothermal laboratory. The event pulled together an unusual mix: Academics, oil company bosses, people hawking heat-transfer equipment, geothermal experts and a few environmentalists.
This was the eighth such conference held at SMU since 2006. Those who have been to several agreed that the biggest difference over time is that the presentations have shifted from blue-sky theory to some data from working projects.
Perhaps the loudest applause for the day was when Will Gosnold of the University of North Dakota ended his talk about a demonstration project with a slide of an email saying it had started generating electricity today.
Another presenter suggested that geothermal power could be an economically sensible replacement for existing coal-fired power plants, particularly if the existing power plants and their transmission lines are near coal mines. That’s the case in Texas.
Susan Petty, president of Seattle-based AltaRock Energy, told the group that many older coal plants will be unable to meet clean-air requirements and will need replacing in the next few years. Waste water used in coal mines could be injected into wells where natural heat would make the water hot enough to drive geothermal power generators, she said.
She did an analysis of five existing coal plants scattered across the country to see if the ground temperatures were hot enough to make the system work. She did not include a Texas site. But she said preliminary data looked promising.
“There is some good potential in some of the areas where Texas coal plants exist,” she said.
Only slightly less speculative was a presentation by Richard Wynn, CEO of San Antonio-based DeepRiver. He’s a geologist who had assembled a system that he says can take waste water from oil and gas drilling — whether conventional or fracking — and use it in multiple ways:
The heat from the water can be used to help power a recycling system that pulls useful solids from the water that are suitable for sale and reuse in other drilling projects.
The remaining brackish, salty water can be put into ponds where the sun heats the heavy, saltiest water at the bottom to near-boiling, while the lighter fresh water at the top acts as a cap, keeping the heat from dissipating. That hot water can be used to drive a generator to produce electricity.
And the whole system makes money. Or at least that’s the theory. Every part of the system has been used someplace. He hopes to have his complete package in place next year in West Texas.
Geothermal power has some advantages over other renewables. The earth stays hot whether or not the sun shines or winds blow. But the current economics of energy production make geothermal growth a hard sell. Oil and natural gas remain relatively cheap. Wind and solar power get some special tax breaks.
In spite of that, the tone at the conference was generally upbeat.
“We all care about the earth,” said Maria Richards, the SMU geothermal lab coordinator, in welcoming the attendees. “We are applying knowledge that is applying hope.”
About 120 people attended this event — about half as many as a few years ago. The crash in oil and gas prices has cut into company travel budgets, organizers said.
The day’s first presenter, SMU geologist Matthew Hornbach, offered a little gallows humor about the effect of the fuel industry crash.
“You guys are the true diehards,” he said. “We’ve gotten rid of the tourists.”