Episode 117 | Generous Geothermal | Geothermal Technologies Office (DOE)
I’ve said it many times, geothermal has tremendous potential, but hasn’t yet captured the imagination the way other renewable energy sources have. Whereas wind and solar are the ones grabbing all the headlines, geothermal has the potential to produce large amounts of clean, constant energy.
In 2019 the Department of Energy’s Geothermal Technology Office (GTO) released a report detailing a plan to put 60 gigawatts of energy on the grid by 2050, a 25-fold increase from today.
Dr. Alexis McKittrick, my guest and program manager at the GTO, says, “There’s still a lot of folks that don’t think about geothermal as an option when they’re considering things like wind and solar. You can’t see geothermal—which is kind of a strength.”
The biggest gamechanger for geothermal are Enhanced Geothermal Systems (EGS), adding water to locations suitable for facilities. GTO believes EGS could increase the number of suitable sites in the U.S. 40-fold. Tests have been conducted on the edge of conventional reservoirs in the West. The most high-profile is DOE’s FORGE project in Utah, which I covered in Episode 83.
Another possibility for geothermal are what Alexis calls “hidden systems,” geothermal + water that haven’t been discovered. The plants in operation today had “surface expression,” like a geyser to tip off scientists the site would be suitable for a plant.
At the time of this episode, GTO had just announced two awards for geothermal. An award to Sandia National Labs will help create a “hidden systems playbook.” Helicopters equipped to perform electromagnetic surveys, combined with surface magnetotelluric surveys will help paint a picture below the surface.
Over at the University of West Virginia, GTO has awarded a team who will continue developing a deep-direct use heating and cooling system. Combined with natural gas, Alexis says this system will replace a coal-fired plant at the campus.
The WVU award will also study the feasibility of geothermal storage, by banking heat into shallow reservoirs while the deep wells produce energy year-round.
“We’re actually looking for technologies where Earth is the battery,” says Alexis. “There’s an almost unlimited potential of storing geothermal energy in the subsurface.”
In addition to producing energy, geothermal could also harvest minerals like lithium for batteries. GTO is working on programs similar to the technology we discussed in Episode 106.
“Geothermal is deployable and it’s available where you are,” says Alexis. “There’s heat beneath our feet everywhere. We just have to be able to harness it.”
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