An inexhaustible source of hydrogen hidden beneath our feet? 🌍

The Earth's crust may contain a source of clean natural hydrogen capable of meeting humanity's energy needs for tens or even hundreds of thousands of years. An international team of scientists has proposed a method to locate and exploit these reserves.


Researchers from the universities of Oxford, Durham, and Toronto have identified the geological conditions favorable for the formation and trapping of natural hydrogen. This gas, produced by chemical reactions in the Earth's crust, could offer a clean alternative to current hydrogen production, which is mostly derived from hydrocarbons.

Hydrogen plays a central role in fertilizer production and is considered a pillar of clean energy systems. However, its current production accounts for a significant portion of CO2 emissions. The discovery of natural reserves could revolutionize its supply.

The scientists have developed a 'recipe' to identify sites where hydrogen has accumulated. This approach combines the study of rock types, temperatures, and fluids necessary for the formation and preservation of the gas. It paves the way for targeted global exploration.

Underground microbes pose a challenge, as they consume hydrogen. The researchers emphasize the importance of understanding their interaction with the gas to preserve reserves. Geologically stable zones, where hydrogen is protected from these microbes, are particularly promising.

Contrary to popular belief, viable hydrogen sources are not found in the Earth's mantle but in the crust. Reserves can be young or ancient, offering a global opportunity.

How is natural hydrogen formed in the Earth's crust?

Natural hydrogen is the result of chemical reactions between water and certain minerals in the Earth's crust, such as olivine and pyroxene. These reactions, called serpentinization, occur at high temperatures and pressures, typical of geological depths.

Serpentinization releases hydrogen by transforming ferromagnesian minerals into serpentine. This process is particularly active in areas where the Earth's crust is fractured, allowing water to circulate and react with rocks.

The hydrogen produced can then migrate to the surface or be trapped in geological reservoirs. The presence of impermeable rocks, such as clays, is essential for forming exploitable accumulations.

What are the advantages of natural hydrogen compared to industrially produced hydrogen?

Natural hydrogen offers several major advantages over hydrogen produced from fossil fuels. First, its extraction does not generate CO2, making it a much cleaner option for the environment.

Second, it does not require the large amounts of energy needed for industrial processes like methane steam reforming or water electrolysis. This significantly reduces its carbon footprint and production costs.

Additionally, natural hydrogen is often associated with other gases, such as helium, which can also be valorized. This co-production can improve the profitability of exploration projects.

Finally, the potential availability of natural hydrogen worldwide could reduce dependence on energy imports and promote greater energy security.