Mantle8 accelerates its push into natural hydrogen, a new strategic challenge for European energy sovereignty

Mantle8, the Grenoble-based company focused on natural hydrogen exploration, has announced a €31 million Series A round to finance a global exploration and drilling campaign dedicated to natural hydrogen. The operation was led by Sandwater, with participation from Breakthrough Energy Ventures, the Ecotechnologies 2 fund managed by Bpifrance on behalf of the French state, as well as IP Group, Wind Capital, and Calderion.

With this transaction, Mantle8 brings its cumulative funding to €37 million. The startup is now entering an industrial phase aimed at demonstrating the existence of commercially exploitable natural hydrogen reservoirs.

Founded in 2019 in Grenoble, the company develops proprietary geological exploration technologies capable of identifying underground accumulations of high-purity hydrogen. Its approach notably relies on HOREX®, a multiphysics 4D imaging platform designed to map active hydrogen systems beneath the Earth’s surface.

The issue extends far beyond a niche energy innovation. For several years, the hydrogen industry has faced a complex economic equation. “Green” hydrogen, produced through electrolysis, remains heavily dependent on electricity costs and associated infrastructure. In this context, natural hydrogen, sometimes referred to as “white hydrogen” or “geologic hydrogen”, is increasingly attracting industrial groups, investors, and governments searching for a lower-cost low-carbon energy source.

Mantle8 estimates that its models could enable production costs around €0.80 per kilogram, significantly below the costs generally observed for green hydrogen in Europe.

“Hydrogen is a crucial component of our future decarbonised industrial system. However, the scale of its role will depend on both its price and its origin,” the company stated.

The central question, however, remains the commercial viability of such reservoirs. While the presence of natural hydrogen within the Earth’s subsurface has long been scientifically documented, no company has yet demonstrated the ability to sustainably exploit large-scale reservoirs under the economic standards of the energy industry.

This is precisely where Mantle8 aims to differentiate itself. “The existence of natural hydrogen is a well-established scientific fact. The challenge lies in identifying high-purity free hydrogen accumulations that are commercially exploitable,” said Emmanuel Masini, founder and CEO of Mantle8. “I am proud that we have developed and patented a complete technological stack to address this critical challenge.”

The newly raised capital will finance the next two years of exploration and, above all, drilling campaigns, a decisive stage in confirming the quality of identified reservoirs. Mantle8 plans to use its technology to select and prioritise several sites before conducting the first industrial tests aimed at measuring reservoir volumes, purity, and quality.

“The next steps consist of identifying the prospects within our pipeline that meet our commercial criteria and then drilling them,” Emmanuel Masini added.

Mantle8’s positioning fits within a broader geopolitical dynamic surrounding European energy sovereignty. Since the energy shock triggered by the war in Ukraine, Europe has sought to reduce its dependence on gas imports and secure new low-carbon energy resources.

Investors are explicitly highlighting this strategic dimension. “Natural hydrogen sits at the intersection of the energy transition and resource discovery, two areas in which Europe must play a leading role as it seeks to strengthen its energy sovereignty,” said Tom Even Mortensen, founder and managing partner of Sandwater.

The funding round also illustrates a broader shift of climate capital toward physical infrastructure and so-called “hard tech” technologies. After several years dominated by decarbonisation software, carbon platforms, and energy optimisation tools, investors are progressively returning to heavy industrial challenges: extraction, geology, strategic materials, and energy infrastructure.

Mantle8 sits precisely at this convergence between mining exploration, geophysical technologies, industrial sovereignty, and the energy transition.

The challenge over the coming months will now be to transform a geological promise into an exploitable energy asset. “The next two years must demonstrate that the active hydrogen systems identified by our technology can produce sustainable and commercially viable flows,” summarised Bart Markus, chairman of Mantle8.

If the company succeeds in demonstrating the existence of a first profitable reservoir, the impact could be considerable for the European energy industry, but also for the broader hydrogen economy, whose main bottleneck today remains production cost.