How much hydrogen awaits us underground?

A global race to locate large underground deposits of ‘geologic hydrogen’ is now happening. This gas could be a zero-carbon fuel. Many new companies are investigating old rock formations, encouraged by predictions that Earth’s crust holds trillions of tons of this resource. No commercially workable reserve has been openly verified, but seeps from deep mines and new stimulation tests show the idea is sound.

Key takeaways

• A worldwide search is focusing on underground ‘geologic hydrogen’ for clean energy.
• USGS projections indicate extractable geologic hydrogen might supply global needs for hundreds of years.
• No natural reserve fit for commerce has been openly located, though mine seeps confirm the process exists.
• Scientists are also trying ‘stimulated’ production, which involves putting water into reactive rock.
• The main hurdle is moving from confirming existence to establishing cost-effective, dependable large-scale production.

The Global Hunt for Natural Hydrogen Reservoirs

Dozens of startups are now involved in this global search. Firms like Australia’s HyTerra and the Bill Gates–backed Koloma have been examining the US Midwest to access ancient oceanic rocks linked to hydrogen generation.

Vast Potential, Scarce Data

US Geological Survey experts calculate that trillions of tons of hydrogen form inside Earth’s crust. They think recovering just a part could meet worldwide demand for centuries. Yet the hunt has so far found little. No one has announced a commercially workable gas reservoir, and public information on discoveries stays limited as companies compete for investment.

While no major commercial deposit has been openly confirmed, smaller finds show the process works. At Ontario’s Kidd Creek mine, researchers calculated roughly 140 metric tons of hydrogen escapes from the mine’s vents yearly. Likewise, at least 200 metric tons flow from the Bulqizë chromium mine in Albania each year.

Evidence from Deep Mines: Quantifying Natural Seeps

At the Kidd Creek mine in Ontario, scientists found ancient brine water containing microbes that consume hydrogen from water-rock reactions or radioactive decay. Geochemists later reviewed data from 35 mine boreholes, finding each one steadily released about 8 kg of hydrogen annually. Scaling this up to the mine’s over 14,000 boreholes indicates around 140 metric tons of hydrogen vents unused every year.

Capturing this volume might power a large part of the mine’s activities. The Bulqizë chromium mine in Albania sees at least 200 metric tons escape yearly. These findings strengthen the case that natural hydrogen generation and movement are real geological events.

Stimulating Production: The ARPA-E Initiative and Omani Experiment

Alongside finding natural reserves, scientists and startups are testing ‘stimulated’ production. This involves injecting water, heat, or catalysts into reactive rocks. ARPA-E funds more than a dozen such projects. Its aim is to speed up the hydrogen-producing reaction by 10,000 times—the rate needed for stimulated H₂ production to be commercially workable.

A hint of success came this year from Oman’s mountains. A team drilled a one-kilometer borehole and put 50,000 cubic meters of water into the rock. Opening the well months later released spewing gas that was 90% hydrogen. This was an encouraging signal, but many uncertainties persist.

The most vital unknown from the Oman test is simple: Did the stimulation create the hydrogen, or was it already there? This shows the outstanding difficulties in proving geologic hydrogen can be made cheaply and reliably for the market.

The Remaining Challenge: From Proof of Concept to Commercial Scale

Geochemist Laurent Truche states the central problem is no longer showing hydrogen exists, but showing it can be made affordably and dependably at market size. Although exploration has gone worldwide, no commercially viable reservoir has been reported.

Demonstrating Practical Use

Scientists cite findings like those from Kidd Creek mine as useful local proofs. Data showed steady hydrogen flow from boreholes. Scaling this up, they estimate about 140 metric tons of hydrogen vents from the mine each year. Capturing it could run a large part of the mine’s operations, proving captured geologic hydrogen has a practical application.

Shifting from Discovery to Development

Experts stress a successful demonstration doesn’t need a massive single find. The field now tackles essential technical and economic issues. Beyond natural discovery, work tests stimulation methods, like putting water into reactive rock to increase output. For these projects, a key issue—highlighted by a researcher’s careful note on the Oman test—is figuring out if the hydrogen is new or was already present.