New study links erosion to natural hydrogen energy potential in mountain ranges

Natural hydrogen gas formed in the subsurface of mountain ranges represents a promising source of clean energy

A new international study published in the Journal of Geophysical Research: Solid Earth shows that surface erosion plays a key and complex role in the formation and accumulation of this underground resource, confirming that the Pyrenees and the Alps could be primary targets for natural hydrogen exploration.

Natural hydrogen and the energy transition

Hydrogen could play a central role in the global energy transition by powering vehicles and decarbonising heavy industrial processes. However, current commercial production heavily relies on polluting fossil fuels, and green hydrogen produced with renewable energy remains costly. Discovering exploitable reservoirs of naturally occurring hydrogen (H₂) within the Earth’s crust offers a potential solution.

In mountain belts like the Alps and the Pyrenees, ancient tectonic plates moved apart millions of years ago to form rift basins, later converging and colliding to build the modern mountain ranges. This tectonic movement brought deep mantle rocks closer to the surface. At these shallower depths, temperature and pressure conditions allow the mantle rocks to react with water, releasing hydrogen gas through a chemical process known as serpentinization. This gas can then migrate and accumulate in porous reservoir rock layers.

The role of erosion

The study, led by researchers from the University of Lausanne (Unil) and the GFZ Helmholtz Centre for Geosciences, used advanced numerical plate tectonic models to evaluate the variables controlling this hydrogen generation. The simulations revealed that surface erosion acts as a delicate regulator of the underground chemical reactions.

The researchers found that erosion impacts hydrogen potential in two contrasting ways:

1. Production booster:

   • Moderate erosion removes the weight of overlying rocks, promoting the uplift of deep mantle rocks toward the surface. This continuous uplift maintains the optimal temperature and pressure conditions required to sustain the serpentinization process.

2. Accumulation destroyer:

   • If erosion is too rapid or intense, it can cool the subsurface too quickly, halting hydrogen production. Extreme erosion can also physically strip away and destroy the porous reservoir rock layers required to trap and store the migrating gas.

Evaluating targeted exploration areas

The computer models also demonstrated that the long-term tectonic history of a region dictates its current resource potential. Specifically, the duration of the tectonic extension phase—the period when the crust was stretching apart long before mountain building began—greatly influences how much mantle rock is accessible for hydrogen production today.

By comparing different mountain systems through these simulation scenarios, the team found that potential varies significantly by region. Out of the areas examined, the Pyrenees displayed highly favourable conditions for natural hydrogen, while the Alps also demonstrated strong potential. The researchers concluded that while these findings help narrow down the geographic search, further regional study will be required to locate exact exploration sites.