Nature: Natural Hydrogen Exploration Accelerates as Industry Races to Produce the Evidence

Natural hydrogen exploration is expanding rapidly across almost 30 countries as companies and researchers test one of the energy sector’s biggest unanswered questions: whether naturally occurring hydrogen can accumulate underground in reservoirs large and productive enough to become a meaningful source of low-carbon energy.

A new Nature article captures a sector moving from geological theory into field testing. Venture capitalists have invested nearly US$500 million since 2023 in companies searching for subsurface hydrogen, while exploration programs are now drilling geological environments ranging from North America and Australia to Africa.

The scientific rationale is increasingly established. Hydrogen can be generated naturally through several geological processes, including reactions between water and iron-rich rocks such as olivine. It can also form through radiolysis, when particles emitted through radioactive decay interact with water molecules.

What remains uncertain is whether those processes can create hydrogen accumulations with the concentration, volume, reservoir characteristics and sustained flow required for commercial production.

That distinction sits at the centre of the emerging natural hydrogen industry.

Researchers have long known that the Earth generates hydrogen, but for decades many assumed it would either be consumed by microorganisms and chemical reactions or escape through rock into the atmosphere rather than accumulating beneath effective geological seals.

Evidence over the past decade has challenged that assumption.

The discovery of a hydrogen accumulation in Mali, described in scientific literature in 2018, demonstrated that hydrogen could remain trapped underground. Additional evidence has come from deep mining environments, including a chromite mine in Albania where researchers reported in 2024 that at least 200 tonnes of hydrogen per year was being released.

Those observations have helped transform natural hydrogen from a largely academic geochemical phenomenon into an exploration target.

The potential scale has added to the interest.

A 2024 modelling study estimated that Earth's subsurface could contain tens of trillions of tonnes of hydrogen. The estimate carries enormous uncertainty and should not be interpreted as a recoverable resource or reserve, but it illustrates why even a very small recoverable fraction could be significant for global energy supply.

The industry now has to determine how much of that theoretical potential exists in reservoirs that can actually be found, drilled and produced economically.

As geophysicist David Waltham of Royal Holloway, University of London, told Nature, the fundamental uncertainty remains exceptionally wide: researchers still do not know whether useful hydrogen accumulations are rare or widespread.

That is why drilling is becoming increasingly important.

Laboratory research can improve understanding of hydrogen-generation mechanisms, reaction rates and interactions between water and different rock types. Geochemistry and geophysics can identify prospective source rocks, migration structures and possible traps.

But wells provide the evidence needed to test whether those models correspond with functioning subsurface hydrogen systems.

One area receiving particular attention is the Midcontinent Rift in North America, where the continent began separating nearly one billion years ago before the rifting process stopped.

The geological event left extensive iron-rich rocks buried beneath parts of the central United States. Exploration companies have subsequently secured acreage and begun drilling in states including Kansas, Nebraska and Iowa.

H2Au CEO Owain Jackson, whose company began drilling in Kansas in August, told Nature that the industry needs more wells and more evidence from them — whether the results are positive or negative.

The exploration challenge extends well beyond locating iron-rich rocks.

Companies need to understand where hydrogen is generated, whether migration pathways allow it to move, whether appropriate reservoirs can store it and whether sufficiently effective seals prevent it from escaping.

Remote sensing, magnetic surveys and other geophysical methods are increasingly being combined to narrow potential drilling locations. Magnetic signatures can be particularly useful because reactions involving olivine and water can generate magnetite, potentially providing an indirect exploration indicator.

Some of the most prospective geological configurations could occur where hydrogen-generating rocks sit close to reservoir formations and impermeable cap rocks capable of trapping migrating gas.

Yet even discovering hydrogen at meaningful concentrations would only answer part of the commercial question.

A viable project would ultimately need to demonstrate pressure, reservoir connectivity, sustained flow, recoverable volume and competitive production costs.

Environmental performance will also require scrutiny.

Although using hydrogen does not produce carbon dioxide at the point of combustion, hydrogen itself can indirectly influence atmospheric chemistry and contribute to warming if significant quantities leak. Some geological hydrogen accumulations could also contain natural gas or other gases requiring separation and management.

The industry's environmental case will therefore depend not simply on the geological origin of the hydrogen but on the emissions associated with drilling, processing, transportation and leakage across the full production chain.

Despite those uncertainties, the next few years could provide substantially more evidence than the sector has accumulated over previous decades.

Exploration wells are being drilled across multiple geological environments, giving researchers an opportunity to compare different hydrogen-generation mechanisms, reservoirs, migration pathways and trapping systems.

University of Oxford geologist Chris Ballentine told Nature that proof of concept could emerge within the next two to three years if the industry is successful — with flowing hydrogen gas representing a critical milestone.

That is increasingly the dividing line between the first phase of the natural hydrogen story and the next.

The scientific case that Earth produces hydrogen is no longer the primary question.

Neither is simply demonstrating that hydrogen can occur underground.

The industry now needs field evidence showing that geological systems can concentrate the gas into reservoirs capable of delivering sustained production at commercially relevant rates.

Full article can be found here [EXTERNAL].