- A new technology injects CO2 into underground basalt formations, turning it into solid rock and releasing hydrogen gas as a byproduct.
- This dual-action approach could transform carbon capture and clean energy by storing CO2 and producing hydrogen simultaneously.
- Basalt formations can store CO2 through mineralization and produce hydrogen through a process called serpentinization.
- Scaling up this natural process could be a solution to climate change, especially with climate targets slipping further out of reach.
- Scientists are exploring how to accelerate and replicate the process in controlled environments to make it more efficient.
What if we could tackle two of the biggest challenges in climate change at once: removing carbon dioxide from the atmosphere and producing clean, abundant hydrogen fuel? That’s the promise behind an emerging technology that injects CO2 into underground basalt formations, where it mineralizes into solid rock — and, under the right conditions, triggers chemical reactions that release hydrogen gas. This dual-action approach could transform how we think about carbon capture and clean energy, turning geologic formations into both storage vaults and fuel generators. With climate targets slipping further out of reach, researchers are asking whether this natural process, scaled up, could be part of the solution.
Can Rocks Store CO2 and Produce Hydrogen Simultaneously?
Yes — under specific geochemical conditions, injecting carbon dioxide into basaltic rock not only leads to its permanent mineralization but can also stimulate the production of molecular hydrogen (H₂) through a process called serpentinization. Basalt, rich in iron and magnesium, reacts with water and CO2 in ways that break down minerals and form new ones, including carbonates that lock CO2 away for millennia. Crucially, when these reactions occur in the presence of groundwater and heat, they can produce hydrogen as a byproduct. This process occurs naturally in places like Oman’s ophiolites and the Lost City hydrothermal field in the Atlantic, but scientists are now exploring how to accelerate and harness it deliberately. Projects like CarbFix in Iceland have already demonstrated the feasibility of CO2 mineralization at scale, and now companies such as Kolos and H2L (Hydrogen from Lava) are building on that foundation to co-produce hydrogen.
What Evidence Supports This Dual-Action Process?
Field studies and pilot projects provide growing evidence that CO2 mineralization and hydrogen generation can be engineered together. At Iceland’s Hellisheiði Power Plant, the CarbFix project has successfully injected over 70,000 tons of CO2 into basaltic rock since 2012, with over 95% mineralized within two years — far faster than initially expected. Researchers from Columbia University and the University of Iceland have shown that the same rock formations can generate hydrogen when exposed to heated water and CO2 under pressure. In 2023, a study published in Nature detailed how iron-rich minerals in basalt reduce water to produce H₂ during carbonation reactions. Meanwhile, Kolos is developing a project in the western United States to integrate carbon storage, hydrogen production, and geothermal energy extraction from the same geological system, aiming for net-negative emissions and carbon-free fuel output. These efforts suggest that the chemistry is not only viable but potentially scalable.
What Are the Skeptical Views and Challenges?
Despite the promise, significant scientific and economic hurdles remain. Some geochemists caution that hydrogen yields from these reactions are currently low and highly dependent on rock composition, temperature, and fluid chemistry. Dr. Peter Kelemen of Columbia University, while a pioneer in the field, notes that “natural hydrogen production rates are slow, and it’s unclear if we can accelerate them without prohibitive energy input.” Others worry that injecting CO2 and circulating water could destabilize rock formations or contaminate aquifers. There are also questions about cost: carbon capture remains expensive, and adding hydrogen extraction infrastructure could increase capital needs. Additionally, while natural hydrogen seeps have been found in France, Turkey, and the U.S., commercial-scale production via engineered systems is unproven. Critics argue that focusing on this technology might divert resources from more mature clean energy solutions like solar, wind, and electrolysis-based green hydrogen.
What Are the Real-World Implications of This Technology?
If successfully scaled, this approach could reshape regional energy and climate strategies, particularly in geologically favorable areas. The Pacific Northwest, parts of India, and the Middle East have extensive basalt formations, making them ideal candidates. In Oman, the government-backed H2Oman initiative is exploring how to leverage its vast ophiolite complexes for hydrogen production, potentially creating a new export industry. In the U.S., the Department of Energy has funded pilot studies to assess co-located carbon storage and hydrogen generation in the Columbia River Basalt Group. Beyond energy, the technology could support industrial decarbonization by providing clean hydrogen for steelmaking, fertilizer production, and long-haul transport. And because the CO2 is permanently stored, such systems could qualify for carbon removal credits, improving their economics. Over time, this could turn geologic liabilities into climate assets.
What This Means For You
This research suggests that nature itself may offer integrated solutions to the climate crisis — using Earth’s chemistry to both remove emissions and generate clean fuel. While not a silver bullet, the ability to store CO2 and produce hydrogen from the same rock could enhance the viability of carbon removal and clean energy systems. For policymakers and investors, it underscores the value of supporting early-stage geoscience innovation. For the public, it offers a reminder that climate solutions may come from unexpected places — even deep beneath our feet.
But key questions remain: Can we engineer these reactions efficiently and safely at scale? And will the hydrogen yields be high enough to justify the investment? As pilot projects expand, the world will be watching to see if this underground synergy can rise to the surface as a real climate solution.
Source: New Scientist