Can Underground Hydrogen Spark a Green-Energy Revolution? The Drilling Rush and an Unknown Resource

The report notes that the basic geochemistry of hydrogen production is well established: the gas forms when iron-rich igneous rock such as olivine reacts with water, and it can also be generated when alpha particles emitted by the radioactive decay of uranium or thorium split water molecules. It translates a mature geochemical understanding previously framed around energy for subterranean microbes into a resource rationale for energy exploration. Presented as established basic geochemistry with a cited reference; no specific experimental data are given.

A 2018 report describing a substantial hydrogen deposit in Mali, together with a 2024 finding that at least 200 tonnes of hydrogen is released annually from a chromite mine in Albania, one of the biggest natural flow rates ever recorded, challenged the old assumption that hydrogen molecules are too small to be trapped underground beneath impermeable rock layers. It marks a shift from 'hydrogen is produced underground but does not accumulate' to 'tappable accumulations may exist', the direct scientific trigger for the exploration rush. Based on a published deposit discovery report and mine measurements, i.e. case-level and observational evidence, not yet enough to establish global accumulation patterns.

The report offers order-of-magnitude figures for resource and investment: a 2024 analysis estimates tens of trillions of tonnes of the gas in the subsurface, a small recoverable fraction could meet projected clean-energy needs for 200 years potentially at or below the cost of fossil fuels, and nearly US$500 million in venture capital has flowed in since 2023. It elevates geological hydrogen from academic curiosity to a potentially economically significant energy option, explaining why capital and drilling activity have gathered so quickly. Analytical estimates and investment tallies rather than proven reserves; the text explicitly states that nobody knows whether large enough deposits exist.

The report stresses that key scientific questions remain open: how quickly hydrogen forms under different geological conditions, how it migrates through rock, where it might accumulate, and how long it persists once trapped. It frames the current stage as an exploration-verification phase about whether the resource exists, rather than a plannable energy supply. Drawn from public statements by several researchers, including David Waltham of Royal Holloway, University of London, Chris Ballentine of the University of Oxford, and Eric Gaucher, who co-leads the natural-hydrogen taskforce at the International Energy Agency; these are expert views and open questions.

This report suits readers who want a quick grasp of the state and controversy of geological hydrogen exploration, including those working in energy policy, investment and Earth science. The setting it addresses is the early verification phase of whether the resource exists: conclusions depend on measurements from several wells expected within months rather than confirmed recoverable reserves, and the 200-year clean-energy and cost figures are explicitly conditional on a small fraction being recoverable at a profit.

Readers should still watch: how large the gap is between total subsurface hydrogen estimates and recoverable reserves; how formation rates, migration paths and trapping times can be quantified under different geological conditions; whether the Mali deposit and the Albanian chromite mine observations generalize to other regions; and where results from the coming months' wells will fall between 'almost nothing' and 'completely everywhere'. In addition, this reading is at summary scope and does not include figures or reference details, so the grasp of specific data sources and calculation methods is limited.