Geological hydrogen has the potential to accelerate decarbonization

The hydrogen hiding in geological formations may be enough to fulfill the anticipated global demand for the energy-rich gas for almost 200 years, according to a recent report from the US Geological Survey (Sci. Adv. 2024, DOI: 10.1126/sciadv.ado0955). That estimate factors in both the growing demand for hydrogen as a vector for decarbonization and the small percentage of subsurface deposits that are likely to be accessible at a reasonable cost.

Coauthors Geoffrey S. Ellis and Sarah E. Gelman analyzed the known mechanisms of subsurface hydrogen generation, such as the reaction of electron-rich inorganic compounds with water, along with the rates at which hydrogen flows upward, gets consumed by abiotic and biological interactions, and accumulates in underground reservoirs.

Though they stress that the uncertainties in their results are large and more data are needed, the researchers estimate that about 5.6 trillion metric tons (t) of hydrogen is trapped in geological formations. On top of that, natural processes make an additional 15 million–31 million t per year.

Most of that will be in deposits “too deep, too far offshore, or too small to be economically recovered,” they write. But we don’t need all of it. Recovering about 2% of the amount of hydrogen that’s available “would meet the entire projected global hydrogen demand for ~200 years,” the authors write.

Morten Stahl, a partner in the geological hydrogen investment fund Natural Hydrogen Ventures, says that Ellis and Gelman’s work is stimulating increased interest from the business community. “Even if the error bars still makes hydrogen exploration very risky, it also offers high rewards for early investors, companies, and society at large, if successful,” he says. “More wells need to be drilled so that ideas can be tested and a feedback loop from the field to the labs can be established.”