New Geothermal energy technologies could make it possible to provide clean baseload power to a microgrid or to ramp up power production when the sun goes down or the wind stops blowing.
Emission-free, geothermal energy has a small footprint and could serve towns or cities over the distribution system without developers having to hassle with interconnection. What’s more, it retains the federal Investment Tax Credit (ITC)–while the Trump administration is phasing out the solar, wind and electric vehicle (EV) credit.
Next-generation geothermal could help meet California’s climate goals
During an Aug. 28 teleconference hosted by The Climate Center, speakers said that geothermal — especially next-generation geothermal —could be a key to meeting California’s ambitious climate goals.
“Widespread deployment of next-generation geothermal could cut clean energy costs by 25% in California," said California Assemblymember Diane Papan during the teleconference.
Papan has introduced two bills to the California Legislature that aim to speed the deployment of geothermal energy. AB 526 would establish a statewide plan to expand the use of geothermal energy production by 2045.
AB 527 aims to streamline environmental reviews for geothermal projects. It proposes exempting exploratory geothermal projects from the California Environmental Quality Act (CEQA) if they meet specific environmental standards.
In addition, Assemblyman Chris Rogers introduced AB 531, which would add geothermal power plants and field development projects to the California Energy Commission’s Environmental Leadership Development Project, making them eligible for certification.
Next-generation geothermal is seen as important to advancing the use of geothermal technology, said Woody Hastings, energy and environmental policy analyst at The Climate Center.
Three ways to deploy geothermal energy
Geothermal technologies include two conventional approaches and a new approach, Hastings explained in an interview.
First, conventional geothermal resources are developed in places with three key ingredients: heat, natural fractures and fluid. The natural fractures and fluid draw the heat to the surface. However, this technology is limited to areas where the ingredients naturally coexist.
Second, enhanced geothermal systems are a conventional geothermal technology where production is enhanced using fracking to open up pores in rock. Typically, there’s no natural water and water is injected to produce steam, Hastings said.
Next-generation geothermal, on the other hand, is a closed-loop system that utilizes one or more wells drilled into hot rock and circulates fluid through the rock to pull heat to the surface. This can be used for direct heating and electricity generation applications.
Scaling geothermal energy to meet demand peaks and valleys
“The thing about next-generation geothermal and closed loop: You can scale it up or down. You could have a 20-MW to 30-MW baseload in a clean microgrid close to the load, with minimal geographic footprint,” Hastings said.
Neil Ethier, interim executive vice president, origination at Eavor, said during the teleconference that the company’s closed-loop system can dispatch, for example, 10 MW/hour for every hour of the day. It can also curtail production in the middle of the day, when solar production is high, and then dispatch the system when the sun goes down.
“You can’t do that with nuclear,” Ethier said.
Nuclear plants tend to have a thick , Hastings explained. (Editors Note: cracks have occurred in nuclear reactor containment vessels at U.S. power plants in the past, with most repaired and at least one incident which was not fixable and resulted in shutting down the reactor).
With closed-loop geothermal systems, no emissions are released into nearby communities.
The environmental advantages of closed-loop geothermal systems
“If you keep it all in a pipe, it’s best for resource conservation and has minimal environmental impacts–not even water vapor,” Hastings said.
No microgrids with closed-loop geothermal systems are now operating in California, Hastings added.
Eavor has a project in Europe and in 2023 signed a contract with the U.S. Defense Department to power a military base.
It’s possible to develop next-generation geothermal in a microgrid, said Ethier. But it doesn’t make sense at this time to deploy microgrids with closed-loop geothermal systems for small installations, he said. “To bring the cost curve down, we need 200-MW-sized chunks,” he said. As costs for smaller projects improve, closed-loop systems could be deployed in remote communities in microgrids, Ethier said.
“You could go anywhere with a microgrid, but scale becomes a critical part of that question,” Ethier said.
Sonoma Clean Power wants to develop 600 MW of geothermal energy
It’s also possible to include geothermal energy in a power provider’s clean resource portfolio. Sonoma Clean Power, a community choice aggregation (CCA), aims to deploy up to 600 MW of next-generation geothermal over the next decade in Sonoma County, said Claudia Sisomphou, public affairs and advocacy manager for the CCA during the teleconference.
“The demand for electricity is increasing with things like electric vehicles, data centers and electrification,” she said. “We need to get serious about meeting that demand with energy that's clean, reliable and affordable.”
Sonoma Clean Power, which has solar, wind and batteries in its resource mix, sometimes needs clean energy in the middle of winter when there’s less sunshine.. The CCA evaluated several clean energy sources and identified next-generation geothermal as the best opportunity, she said.
Geothermal power is a good clean-energy opportunity because hot rocks can be found everywhere, as long as developers drill deep enough–generally 3,000 to 12,000 feet, Hastings said. Deep drilling can be as deep as 2 miles below the surface,
“It’s everywhere and that’s why it’s so exciting,” he said.
