There is enough clean energy under our feet to satisfy America’s electricity demand for 30,000 years, according to the U.S. Department of Energy.
But a big question remains: How do we tap into it?
The DOE is ramping up a research effort examining just that. Geothermal energy, energy generated and stored inside the Earth in hot water and rocks, for decades has been harnessed to heat buildings and spin turbines that generate electricity. But experts say it has even more potential.
The DOE’s goal is to build a field laboratory called FORGE, the Frontier Observatory for Research in Geothermal Energy. It would examine how to extract energy from wells dug thousands of feet below the surface.
Idaho National Laboratory wants to host FORGE, and even picked a location near Arco. But it has plenty of competition to host the facility.
Earlier this week in Reno, Nev., the DOE announced $2 million in grants to fund geothermal research teams from five states, including Idaho. Teams from Utah, Nevada, California and Oregon also think they have a good location for FORGE.
“It turns out there’s quite a bit of hot rock like this around the country but it’s hard to get to,” Lynn Orr, DOE undersecretary for science, told the Associated Press.
With the money, the five teams will continue to refine their plans and gather local support for a geothermal lab. Next year, the DOE will narrow the field to three teams. The three will share an additional $29 million in federal research money. Finally, a winner to host FORGE will emerge, with construction beginning as soon as 2018.
“I fully expect to win this, because I think our site is the best, and our team is top-notch,” said Rob Podgorney, who heads up INL’s Energy Resource Recovery and Sustainability program.
Conventional geothermal sites are limited to areas that already have heat, fluid and permeability, or pathways, for the fluid to heat up. Steam powers a turbine, which generates electricity.
“But unfortunately, a lot of places where you find all three of those things (heat, fluid and pathways), they are in the middle of nowhere,” Podgorney said.
With FORGE, the DOE hopes to develop “enhanced” geothermal systems, which would be cheaper and not so tethered to specific geographic locations.
“Anywhere in the world, if you drill deep enough, you’re going to hit temperatures hot enough to create electricity,” said Tom Wood, the University of Idaho associate director at INL’s Center for Advanced Energy Studies.
Such enhanced geothermal systems will require drilling several wells down to 10,000 or 12,000 feet. At that depth, Earth’s radiation heats the rock up to 350 degrees or more, yet sufficient fluid and pathways are often lacking.
To fix this problem, water is injected from the surface into those subterranean spaces, in order to create fractures that open up small pathways.
This allows more water to be heated up by the rock, inside a limited reservoir area. After it heats up, the water is drawn back to the surface from another well shaft. It’s flashed into steam, which drives a turbine, and creates electricity. The cycle then starts over. Researchers hope most of the water will be reused.
“The technology’s there, but it hasn’t really been applied,” Wood said.
Researchers will need to answer a number of key questions at FORGE, from how well the water stays in the underground reservoir, to the most efficient methods for bringing it back to the surface and creating electricity.
“We need to make it so industry is comfortable to adopt this type of technology,” Podgorney said.
Geothermal is a renewable energy source. But it has a key attribute other renewables don’t: Baseload power.
“Solar and wind are intermittent,” Podgorney said. “But with geothermal, you know it’s going to be there when you need it.”
Existing geothermal plants, such as The Geysers in California, can produce power 24 hours a day for years, until the steam runs out, or the rocks begin to cool off. Geothermal plants also have a smaller geographic footprint than solar or wind farms, Podgorney said.
“It’s a small portion right now of the renewable energy mix,” he said. “But if we can improve these (geothermal) technologies, as we aim to do with FORGE, it could unlock the order of tens to hundreds of gigawatts of (power) generation.”
The DOE estimated enhanced geothermal systems could eventually generate enough electricity to power up to 100 million U.S. homes.
“That right there would make it a serious contributor to a clean energy future in this country,” Podgorney said.
There are potential downsides to enhanced geothermal power generation, however. Similar to fracking — the controversial process of injecting fluid into the ground to release natural gas — early testing of enhanced geothermal methods have been known to cause “micro” earthquakes.
Wood said he’s also heard concerns about the East Snake Plain Aquifer, considering such a geothermal project on the INL site would require drilling well below the aquifer. But he said the wells could be sealed up to avoid contamination.
As for the earthquakes: “We have a good buffer zone created by 890 square miles of the INL site,” Wood said.
In addition to his INL duties, Podgorney serves as director of the Snake River Geothermal Consortium.
The consortium includes a number of regional universities, as well as the University of Oklahoma. Lawrence Livermore National Laboratory, National Renewable Energy Laboratory, several geothermal industry players, and state and federal agencies are also onboard.
All the consortium members want to bring FORGE to INL, Podgorney said. It’s a big reason he thinks Idaho has a strong shot at winning the competition.
In addition, more than 40 letters of support have trickled in since last year from various Idaho stakeholders, including Idaho Falls Power, Shoshone-Bannock Tribes and Gov. C.L. “Butch” Otter.
“People believe in it,” Podgorney said of geothermal. “It may seem lofty, but we’re going to change the energy future. Why shoot low?”
Luke Ramseth can be reached at 542-6763. Twitter: @lramseth