Sonoma Clean Power Spearheads Next-Gen Geothermal Power at The Geysers with Early Results

California’s goal of producing more round-the-clock power from The Geysers may be in reach, as a demonstration there of next-generation geothermal energy technology has become operational and is said to be generating promising early results.

The project is part of a multipronged effort to increase electrical output for the North Bay and throughout California from what’s still the world’s largest geothermal energy field despite declining steam production at the plants in the Mayacamas range between Sonoma and Lake counties.

Oklahoma City-based GreenFire Energy last month announced that its first commercial demonstration system, installed in a low-output well at The Geysers, is now fully operational. The well, previously nearing idle status, is producing sustained flow rates of 300–350 gallons per minute with unexpectedly high-output temperatures of 310 degrees Fahrenheit, all within a closed-loop system.

GreenFire’s patented “GreenLoop” system relies on pipe-enclosed fluid that goes down into the well cool, gets heated then comes back up to release the heat into a electricity-generation system. This fluid has a lower boiling point than water, requiring less heat to produce steam.

Such closed-loop systems don’t rely on groundwater to infiltrate the hot rock to be turned into steam and captured at the surface. Highly treated wastewater has been pumped up from Lake and Sonoma counties to injection wells over the past decades to recharge that steam reservoir.

Because of depletion of that reservoir and concerns from environmental regulators about dangerous gases emerging from deep underground, some wells have been closed and steam production at some remaining wells has declined.

Generation at The Geysers peaked at about 2 gigawatts in 1987 and has been between 600 and 700 megawatts in recent years. A megawatt powers about 1,000 typical homes.

“This is a breakthrough — not just for our team, but for the future of geothermal,” said Rob Klenner, president of GreenFire Energy, in the announcement. “We’re delivering on our promises to show how next-gen technology can provide high-performance power with real commercial applications.”

The company’s stated goal is to bring 150 megawatts of geothermal capacity online by 2030, targeting sectors from manufacturing to data centers.

The Geysers project — hosted by Calpine Corporation subsidiary Geysers Power Company at its Bear Canyon Unit 2 plant in Lake County — is designed to test how efficient the energy transfer can be between the hot well and the loop liquid while preserving water mass in the steam-dominated reservoir.

Calpine and GreenFire didn’t respond to requests for comment.

California is betting big on geothermal energy for its green grid, but development faces long permitting delays. Now there’s a three-pronged effort in Sacramento to help the Golden State better compete with quick-turn permitting elsewhere in the West.

Funded in part by a $2.7 million California Energy Commission grant, the demonstration includes two completed seven-day production tests and a nearly finished steady-state performance test. GreenFire officials said the results signal the system’s scalability to other low-output wells, a major step forward in revitalizing aging geothermal infrastructure.

GreenFire’s success arrives at a pivotal time. Sonoma Clean Power has been spearheading a GeoZone program to attract next-generation geothermal projects to the North Bay. GeoZone is a partnership with local counties and three energy company developers to create a renewable energy development zone focused on geothermal and other clean sources to serve Sonoma, Mendocino and Lake counties.

"We're trying to make California the place that developments can drive forward fastest," said Miles Horton, legislative policy and community engagement manager for the power agency.

The agency is backing two key bills aimed at creating a more competitive regulatory environment. Assembly Bill 527 would provide California Environmental Quality Act exemptions for geothermal exploration. AB 531 would allow geothermal projects of any size to use a streamlined permitting process, while the current cutoff is for plants above 50 megawatts.

"We have the demand here in California for clean baseload power," Horton said.

The ultimate goal remains expanding geothermal capacity by 600 megawatts in The Geysers, which Horton compared to 2 gigawatts of solar production capacity because it generates whether the sun is shinging or not.