THE GROUND THAT BURNED to the foundations during Lake County’s Valley Fire in 2015, on a fault the U.S. Geological Survey rates capable of a magnitude 7 earthquake, is now one of the most promising places in California to hunt for a fuel the state has almost no rules for.
A Denver startup called Koloma — backed by Bill Gates’ Breakthrough Energy organization and Amazon’s climate fund — has spent the past year quietly mapping the rock under Cobb and Kelseyville, in one of California’s poorest counties, for natural hydrogen. The roadside survey is finished. The company briefed two county supervisors out of public view. And so far, no one has said what it found.
Hydrogen is the cleanest fuel going: burn it, or run it through a fuel cell, and the only exhaust is water — no carbon dioxide, no soot. The catch is that almost all the hydrogen used today is manufactured from natural gas, an energy-hungry process that throws off the very carbon that hydrogen is supposed to displace. Natural hydrogen turns that on its head.
Sometimes called “white” or “gold” hydrogen, it’s just what it sounds like: hydrogen gas the earth makes on its own, sitting underground waiting to be tapped like oil — clean energy to drill for instead of cooking up. The earth makes it where iron-rich rock deep underground reacts with water over millions of years.
Koloma uses passive sensors to read the earth’s natural electric and magnetic fields in search of rocks that could trap hydrogen. The work makes no noise, uses no water, and leaves nothing behind.
The reaction is called serpentinization, and Lake County sits on close to ideal conditions for it — the same hot, fractured, iron-heavy ground that feeds the Geysers geothermal field spanning Lake and Sonoma counties in the Mayacamas range. A 2025 study in the International Journal of Hydrogen Energy by University of Houston researchers, with a co-author from Shell, named the Clear Lake Volcanic Field as the leading natural hydrogen target in Northern California. Any deposit would sit about a mile and a quarter down, along the Collayomi fault.
What Koloma has done so far is not drilling. Its crews ran a magnetotelluric survey — passive sensors set on the ground overnight that read the earth’s natural electric and magnetic fields, looking for the kind of sealed rock structure that could trap hydrogen. The work makes no noise, uses no water, and leaves nothing behind. Along county roads, it required an encroachment permit from Lake County Public Works. On private land, it required only a handshake with the landowner and no county permit at all. The roadside portion is now complete; the county’s chief deputy administrative officer Matthew Rothstein said in a written response to a question.
Whether the gas is actually down there in useful amounts, and whether it stays put rather than leaking through the same faults that made it, is the open scientific question. Koloma’s survey was designed to map the structure that could hold it, not the gas itself. The data is not public.
Survey maps geology, not hydrogen itself
The researchers whose work flagged this ground say Koloma’s method can confirm the setting but not the prize. A magnetotelluric survey measures how easily electric current moves through rock. That can light up fault zones, trapped fluids and the kind of seal that would have to hold any gas in place — conductive clay, say, or the hard igneous rock that caps the world’s only producing natural-hydrogen field, in Mali. What it can’t see is the hydrogen itself.
“It remains very challenging to directly map and locate a geological hydrogen reservoir,” Yawei Su, lead author of the University of Houston study, said in an email, noting that hydrogen can mix with methane underground and that even good geophysics mostly shows where the conditions are right, not whether the fuel is there.
His co-author, University of Houston geophysicist Jiajia Sun, was blunter: a favorable survey “would not prove that hydrogen is present,” he said. “MT does not uniquely detect hydrogen.”
What it can do, Sun said, is answer a question the existing maps cannot — whether the Collayomi fault has both the cracks to circulate water and a seal to keep any hydrogen from leaking back out.
Koloma broke a long public silence on June 19, after months of declining interviews, with a brief written statement that said nothing about its findings.
“The Cobb Mountain magnetotelluric survey work remains ongoing and is expected to continue through the summer,” the company said in a statement attributed to land manager Kyle Handy and relayed by Ben Colombo, who handles Koloma’s outside communications. “Based on an analysis of the final results, Koloma will determine next steps in consultation with our local community partners.”
The statement also signaled the work is not over: Rothstein had described the roadside survey as complete, while Koloma called its survey still ongoing — most likely a reference to the portions on private land, which need no county permit and are not tracked. The company did not answer questions about what the data shows, how it would handle California permitting, or whether it plans to drill.
Billions flow into search for clean underground fuel
Koloma has raised more than $394 million, according to its federal securities filings, from a roster heavy with climate money: Gates’ Breakthrough Energy Ventures, Amazon’s Climate Pledge Fund, Khosla Ventures, United Airlines’ green-aviation fund and, since late 2024, Japan’s Mitsubishi Heavy Industries and Osaka Gas.
The pull is around-the-clock clean power. Tech companies racing to feed power-hungry artificial intelligence data centers want electricity that runs 24 hours a day without carbon. Goldman Sachs projects U.S. data center demand will more than double by 2027. Airlines need cheap hydrogen to make low-carbon jet fuel. And a federal tax credit pays up to $3 for every kilogram of clean hydrogen produced — a credit Congress voted last year to start phasing out at the end of 2027, putting a clock on anyone who wants it.
Koloma is not alone in the bet. At least two other startups are chasing the same California rock for the same data center customers, and one of them already has a foothold in Lake County the public hasn’t heard about.
Fremantle Lake CA LLC, an arm of the Houston hydrogen startup Anning Corp., has asked the state for a permit to drill one exploratory well in Lake County, to find out whether hydrogen can be pulled from the ground there at a profit. The well would sit on California “school lands”: parcels the federal government gave the state at statehood in 1850, to be held in trust and earn money for public schools.
The State Lands Commission manages what’s left of that grant, along with the minerals beneath it, and the royalties it collects go to the fund that pays the state’s retired teachers. Anning, like Koloma, is backed by Bill Gates’ Breakthrough Energy, a different arm of it but the same money.
“We are currently progressing environmental review, tribal engagement, and the associated studies required to support permitting and exploration activities,” CEO Sophie Broun, a former Chevron geoscientist, said in a written response to questions, adding that the company aims to finish permitting “over the coming year” and then move to exploratory drilling.
Regulations lag fast-moving hydrogen industry
Where Koloma worked private land on a handshake and no county permit, Fremantle’s bid sits on state ground with an application pending. A third company, Vema Hydrogen, has signed a supply deal with a data center operator for California hydrogen. But Koloma is the only one of the three known to be working in Lake, Mendocino and Sonoma counties.
It is working in a near-total legal vacuum. The federal law that governs mining on public land, written in 1920, does not mention hydrogen. California has no law defining natural hydrogen as something a company can own and produce, and no dedicated permit for drilling it. Who even owns the hydrogen under a given parcel — the landowner, the holder of the mineral rights or the federal government on the public land that threads through the target zone — is unsettled in California courts.
County records show how far the relationship had gone before any of it was public. Koloma first approached Lake County in the summer of 2025 under the name Timberline Exploration, then went public under its own name.
It asked the county to be the lead agency for the environmental review of its own future drilling and offered to pay for the consultant who would run that review, according to county emails released to Bay City News under the California Public Records Act. No drilling application had been filed as of those records.
Koloma’s record in another state has already drawn a federal flag. In Minnesota, a Koloma subsidiary ran a 69-mile survey on county road permits. U.S. Forest Service officials said the work should have required a separate federal authorization that was never obtained. Lake County’s target zone overlaps Bureau of Land Management ground, the Mendocino National Forest and the Berryessa Snow Mountain National Monument.
Locally, the public process has also been thin. In January, the Lake County Board of Supervisors created a two-member ad hoc energy committee. Three supervisors — Jessica Pyska, Helen Owen and Bruno Sabatier — wanted on, but an ad hoc committee is exempt from California’s open-meeting law, the Brown Act, only if it stays below a quorum, so just two of the five could serve.
Sabatier agreed to step aside, then noted he and Owen had already been meeting with developers and interested parties: “There are some conversations that have gone pretty deep.”
Adding a third supervisor to the same discussions, he warned, could amount to a serial meeting — the kind of behind-the-scenes daisy chain the open-meetings law forbids.
“I think there’s ways to remedy that, so we don’t have Brown Act violations going forward,” Pyska said. The board seated Pyska and Owen. Because it stays that small, the committee’s meetings are not noticed, recorded or open, and Koloma gave it what Rothstein called a “high-level overview,” with no date, minutes or recording.
Questions remain before any drilling can begin
None of Lake County’s seven federally recognized tribes has been consulted. Under state law, that step isn’t required until a project reaches environmental review.
Owen, the District 1 supervisor and one of the committee’s two members, said in an interview that she has met with Koloma and has been trying to satisfy herself the project is safe.
“I’ve tried to do some research to see if there’s any downside to it. At this point I have not found one — because of course, if they’re interested in drilling, they’re not going to tell us anything on the negative side,” she said.
She said she had pressed the company on waste, pointing to an uncleaned PG&E geothermal waste site on Butts Canyon Road, and argued the county needs to “be asking those questions before anything else comes in.”
None of that is in play yet. A passive survey moves no fluid and triggers nothing. It is the drilling that would carry risk, and the nearest precedent sits next door. At the Geysers geothermal field, the USGS says decades of injecting water into hot rock have induced earthquakes. A peer-reviewed study by Lawrence Berkeley National Laboratory scientists of a single injection well there recorded local quake rates rising roughly ninefold.
Exploration drilling alone is a much weaker trigger, and no one has proposed injection in Lake County. But the prize carries its own asterisk. The Clear Lake Volcanic Field is, in the USGS’s words, “still active.” And natural hydrogen is rarely pure — across 331 sites worldwide it averages about 40%; the rest mostly methane and carbon dioxide — so “clean” isn’t a given even if the gas is there.
If Koloma decides to drill, the rules finally get real: a county permit, environmental review and a state drilling notice. That is the point at which the questions Lake County hasn’t had to answer come due — who writes the rules for a fuel the state hasn’t defined, on land that has burned twice in a decade and sits on a creeping fault?
For now, the work runs through the summer, the company says — and Koloma still won’t say what the rock beneath Cobb is telling it.