Geologic Hydrogen: A Hidden Energy Source Emerges

Geologic Hydrogen: The Gas Beneath Our Feet

Geologic hydrogen is shaping up to be one of the more intriguing energy stories of the decade, and the evidence keeps stacking up in unexpected places. Deep inside a Canadian mine, researchers have been tracking something remarkable: hydrogen gas that has been naturally generated underground for eons, quietly venting out of boreholes without anyone doing anything to make it. The question now is whether we can actually use it.

The story starts in the 1990s, when geochemist Barbara Sherwood Lollar descended into the Kidd Creek mine in northern Ontario. That mine cuts more than three kilometers into the ancient root of North America, and it was there that her team found water that had been trapped underground for over a billion years. But that ancient brine wasn't just old, it was alive. It turned out to be home to living microbes that feed on hydrogen, which is produced in reactions between the water and the surrounding rock. We've known such places exist, but finding one this deep changes everything. It's a stunning discovery.

Decades later, Sherwood Lollar, now at the University of Toronto, went back to the team's hydrogen data with a different question in mind. Could there be enough of this gas in the mine to serve as a useful source of zero-carbon fuel? So she asked. And the answer, buried in those old numbers, wasn't just a yes or no,it was a challenge to rethink what counts as energy. That's a big ask. But the numbers held a spark, and she wasn't about to let it fade.

"If we can set some smart minds into figuring out how to hook it up and use it, then we've got a win for this nascent economy," she says.

The stakes here are real. Hydrogen fuel has long been pitched as a flexible energy source, but making it usually releases a lot of greenhouse gases and needs more energy than the gas holds. That is the fundamental problem with the hydrogen economy as currently imagined. But if you can tap ready-made underground reservoirs, the so-called geologic hydrogen, the whole equation changes.

Where Does Underground Hydrogen Come From?

Natural hydrogen forms underground in a few distinct ways. One mechanism splits water molecules through chemical reactions with iron-rich rock. But the process at Kidd Creek is different, driven by the radioactive decay of other elements in the Earth's crust, and both pathways can produce gas that eventually pools in rock formations, just waiting to be tapped.

The hunt for these reservoirs has gone global. Dozens of startups have launched exploration efforts, including the Australian firm HyTerra and Koloma, a company backed by Bill Gates, and that's a serious push for a very young industry. So both have been poking around the US Midwest, targeting ancient oceanic rocks that are associated with hydrogen production. It's a gamble. But they're betting big.

The potential scale is staggering. Researchers at the US Geological Survey have estimated that trillions of tons of hydrogen are produced within Earth's crust. Even if a small fraction of that could be recovered, it could meet global hydrogen demand for centuries.

But here's the awkward part: nobody has found a commercially viable reservoir yet. The search has come up short. And public data on what's been found remains scarce, since companies are jockeying for position and competing for investment, which means outsiders can't gauge the true scale of what's out there. So we're left guessing.

What Kidd Creek Actually Shows

Sherwood Lollar and her colleague Oliver Warr decided to take a different approach. So they stopped hunting for new reservoirs entirely. Instead, they went back to data they had been collecting for years, a deep well of hydrogen measurements pulled from 35 boreholes at Kidd Creek mine, gathered over more than a decade. It was a patient, quiet move. And that patience paid off.

What they found was consistent and telling. Each borehole released an average of eight kilograms of hydrogen per year. Extrapolating that to the more than 14,000 boreholes at the mine, the researchers calculated that around 140 metric tons of hydrogen is flowing unused out of the mine's vents annually.

The findings, published earlier this year in the journal PNAS, aren't world-changing in terms of raw energy output. But Sherwood Lollar argues they matter for a different reason, one that hinges on practicality rather than sheer scale. If all that hydrogen could be captured, it could power a substantial portion of the mine's operations. That's a big if. Still, it would serve as a valuable local demonstration that geologic hydrogen can actually be put to practical use, proving the concept where it counts. So it's about proof, not power.

The Numbers Break Down Like This

• Each borehole at Kidd Creek releases an average of 8 kilograms of hydrogen per year
• The mine has more than 14,000 boreholes in total
• Combined, that adds up to roughly 140 metric tons of hydrogen escaping annually
• The measurements were collected over more than a decade

Laurent Truche, a geochemist at the University of Grenoble Alpes in France, sees the Kidd Creek results as part of a bigger picture, one that stretches far beyond a single mine site. It's genuine. The findings add to "the growing evidence that natural hydrogen generation and migration are genuine geological processes," he says, and that's a claim we can't ignore.

Truche knows a thing or two about this. In 2024, his research team reported that at least 200 metric tons of hydrogen flow out of the Bulqizë chromium mine in Albania every year. That is a substantial amount, and it comes from a mine that was never designed to capture gas.

"The remaining challenge is not proving that natural hydrogen exists, but proving that it can be produced economically and reliably at commercial scale," Truche says.

The Stimulation Question

Here is where things get interesting. Proving that hydrogen exists underground is one thing, but it's not the real challenge. Getting it out in commercial quantities is another. So here's the twist: we've got a possible shortcut, one that might let us skip the slow, costly grind of drilling and extraction altogether. But there might be a way to speed things up.

Researchers and startups are now testing a bold idea: inject water, heat, or catalysts into reactive rocks that naturally generate hydrogen. That's the pitch. They're trying to speed up a process that, left to its own devices, would take millennia, so they're essentially trying to compress geological time into a human timescale, and the payoff could be a clean fuel source without drilling for gas. But it's not simple. The rocks are deep, the conditions are harsh, and nobody's sure if the acceleration can work at scale. So they're watching, waiting, and poking.

More than a dozen of these projects are funded by ARPA-E. That agency has set an ambitious goal, one that could reshape clean energy economics: accelerating the hydrogen-producing reaction by a factor of 10,000. It's a staggering number. And it's the rate at which researchers estimate stimulated hydrogen production would become commercially viable, so the entire enterprise hinges on hitting that exact multiplier.

And there is early evidence that the approach could work. Earlier this year, in the mountains of Oman, a team drilled a one-kilometer borehole and injected 50,000 cubic meters of water into the rock. When they opened the well several months later, gas was spewing out. The composition was 90% hydrogen.

"It's bubbling with gas," Jo Shannon, a geoscientist at the University of Southampton in the UK, told attendees at the European Geosciences Union conference in May.

The Catch Nobody Is Talking About

But there is a catch, and Shannon was careful to flag it. There are still plenty of unknowns, and the biggest question is simple: Is the hydrogen coming from that well in Oman truly created by the stimulation, or was it already there before?

That distinction matters enormously. If the hydrogen was already present, then stimulation is just a fancy way of accessing a pre-existing resource. If the injection actually created new hydrogen, then the technology could be deployed anywhere the right rocks exist.

The difference between those two scenarios determines whether geologic hydrogen becomes a niche curiosity or a genuinely scalable energy source.

Sherwood Lollar's work at Kidd Creek points in a hopeful direction. The fact that hydrogen has been flowing consistently from those boreholes for over a decade, without any intervention, suggests that natural generation is ongoing and reliable. That is a good sign for the long-term viability of the resource.

Consistency at a small scale isn't the same as commercial viability at scale. That's a hard truth. The Kidd Creek hydrogen, if fully captured, would power a meaningful chunk of the mine's operations, so it stands as a useful demonstration of what's technically possible in a contained setting. But it's not the kind of output that would transform the global energy system. Not even close.

The path forward, as Truche frames it, is about economics and reliability, not existence. The gas is there. The question is whether we can get enough of it, cheaply enough, to matter. The answer to that question is still very much in the open.