Clean hydrogen is necessary. We can’t power every industrial process with renewable electricity alone. Some things—like making steel or fertilizer—just won’t work on wind or solar directly.
We need a substitute. Hydrogen fits. Burn it and you get water. No greenhouse gases. But right now almost all hydrogen comes from fossil fuels. It’s dirty. To make it green, you split water with electricity, usually from wind or solar. Expensive. It also consumes huge amounts of energy that we need for other things like replacing coal plants.
So we look at rocks.
The Natural Problem
Nature makes hydrogen deep underground. Sometimes it gets trapped. We could mine it like natural gas.
“I think it’s a very special case,” says Orsolya Gelencséér of the University of Texas at Austin.
Tiny hydrogen molecules leak everywhere. Finding enough of it to matter is hard. There is a village in Mali called Bourkélébougou extracting pure natural hydrogen on a tiny scale. That’s about it.
Most experts think natural reserves are limited. We can’t wait for geology to hand us the prize on a platter. We have to make it happen.
Stirring the Pot
The idea is “stimulated hydrogen production.”
You drill into specific rock types—usually volcanic rocks rich in iron. You pump in water. The rock reacts with the water, a process called serpentinisation, and creates hydrogen.
Simple, right?
Add one twist. Pump in water mixed with CO2 instead of plain water.
Gelencséér’s lab tests suggest the CO2 does double duty. First, it creates carbonic acid, which eats into the rock surface, exposing more iron for the water to react with. More reaction means more hydrogen.
Second, the CO2 gets locked away. It mineralizes into solid carbonates. You are capturing carbon dioxide and turning it into rock. While generating hydrogen.
It’s a double win if the math works.
The Lab Results
They tested volcanic rock samples in a pressure vessel. Simulated depth, heated to 90° Celsius.
Control group: Water with inert argon.
Experimental group: Water with CO2.
The CO2 side released more hydrogen. As expected, the CO2 turned into stone.
But here is the bottleneck.
They extracted 0.5 percent of the theoretical hydrogen possible. To be economically feasible, they need 1 percent. It’s not a huge gap, but in engineering, half a percent of a resource is a lot of missing profit.
How do you close the gap?
Go deeper.
Higher temperatures speed up the chemical reactions. It costs more to drill that deep. But you gain another benefit. Geothermal heat. You could generate power while mining the gas and locking up the carbon.
Is It Viable?
Globally, these iron-rich rocks are everywhere. Even at low efficiency, the total output could dwarf the 100 million tons of hydrogen produced today.
“There’s no silver bullet.” — Barbara Sherwood Lollar, University of Toronto
Lollar thinks we should mine what exists. She points out that a mine in Ontario is already venting 140 tons of natural hydrogen a year into the air. We are literally losing it.
Patonia, a researcher at Oxford, notes the business model is evolving. If companies can charge fees for sequestering CO2 while producing hydrogen, the project becomes less risky. Investors like guaranteed revenue streams.
“A number of groups and start‑ups are exploring variations of this concept,” Patonia says.
We need to move fast. The technology is unproven at scale. The costs are unclear.
But the alternative is sticking with dirty hydrogen and letting CO2 keep rising.
Or do we just keep hoping nature gives us enough gas?
Probably not. We drill. We test. We see what comes out.
