• Mantle8 raised €31 million in Series A funding to advance a global exploration and drilling campaign for high-purity natural hydrogen.
• The company projects production costs as low as €0.80 per kilogram, a level that could reshape clean hydrogen economics if proven at scale.
• The raise brings Mantle8’s total funding to €37 million, or $44 million, as Europe looks for sovereign, low-carbon energy sources.

France based Mantle8 has raised €31 million in Series A funding to test whether natural hydrogen can move from scientific promise to commercial production.

The round was led by Sandwater and included Breakthrough Energy Ventures, Bpifrance’s Ecotechnologies 2 fund, IP Group, Wind Capital and Calderion, an Audacia-backed investment platform. Mantle8 will use the capital over the next two years for what it calls the world’s most advanced natural hydrogen exploration and drilling campaign.

The company’s target is clear: identify and confirm the first commercially exploitable reservoir of high-purity natural hydrogen.

A New Test For Clean Hydrogen Economics

Hydrogen remains central to industrial decarbonization plans. Yet its role depends heavily on cost, source and scalability. Green hydrogen has faced pressure from high power prices, infrastructure needs and slow project development. Natural hydrogen offers a different route, if companies can prove it exists in commercially useful accumulations.

Mantle8 says its proprietary exploration technology can reduce exploration risk and cost by identifying viable natural hydrogen reservoirs before drilling. Its economic models project production costs as low as €0.80 per kilogram.

If proven, that price would materially lower the average cost of clean hydrogen supply. It would also give Europe a potential domestic energy source at a time when industrial policy is closely tied to energy security.

“This raise reflects the growing conviction among leading clean tech investors that natural hydrogen is a resource worth pursuing at scale,” said Emmanuel Masini, Founder and CEO of Mantle8. “The existence of natural hydrogen is a well-established scientific fact; the challenge has been finding free gas accumulations of high-purity hydrogen that are commercially viable. I’m proud that we’ve built and patented an entire technology stack to answer this critical challenge, meeting the expectations of our existing shareholders.”

“The next steps are to identify the prospects in our pipeline that meet our commercial hurdles and drill them. I’m excited to welcome investors who have a long history of involvement in subsurface resources, sovereign investments and ecosystem building,” he added.

Investors Back A Subsurface Bet

Mantle8’s model sits between clean technology, geology and resource development. The company is using its technology stack to identify and rank opportunities across a global development pipeline. It will then drill selected sites to assess volume, purity and reservoir quality.

“We built Sandwater to back exceptional founder teams with the technical depth and operational rigour to solve critical challenges and deliver solutions that lead to a better future,” said Tom Even Mortensen, Founder and Managing Partner of Sandwater. “Mantle8 is exactly that kind of company. Emmanuel and his team have built truly proprietary exploration technology, validated it in the field, and now have a clear plan to move into the commercial phase. Natural hydrogen sits at the intersection of energy transition and resource discovery, two areas where Europe must lead as it seeks energy sovereignty. This is a demanding challenge but with the potential to create a new clean energy source, which is what we need and why we see in Mantle8 the opportunity for outsized impact and return.”

For investors, the appeal is not only climate impact. It is also the possibility of building a new upstream clean energy category with lower input costs than manufactured hydrogen.

RELATED ARTICLE: Mantle8 Secures $2.2M EU Just Transition Fund Grant For Natural Hydrogen Tech

“Geologic hydrogen is one of the most surprising energy developments of the past decade, with the potential to play a significant role in the global energy mix,” said Carmichael Roberts of Breakthrough Energy Ventures. “The Mantle8 team has made impressive progress in advancing its rigorous, geology-driven approach to exploration, and the team continues to execute on targeting the first commercially exploitable reservoir of high-purity natural hydrogen.”

Europe’s Sovereign Energy Push

The Series A follows a busy period for Mantle8. In 2025, the company raised a €3.4 million Seed Round led by Breakthrough Energy Ventures. It also completed the world’s first 4D imaging of an active underground natural hydrogen system using HOREX® at its Hydrogeco project in the French Pyrenees.

Earlier this year, Mantle8 received a €2.06 million grant from the EU Just Transition Fund to industrialise its core exploration technologies.

“Natural hydrogen represents a strategic opportunity for France and for Europe,” said Alexandre Wagner, Investment Director at Bpifrance Green Venture. “Mantle8 combines a proprietary exploration technology stack with a clear path to commercialization. Backing this company, aligns with our mandate to accelerate the energy transition through sovereign, low-carbon solutions that could be developed before the end of the decade.”

The next phase will determine whether Mantle8 can turn exploration data into sustained commercial flow. For executives and investors, the risk profile remains closer to resource discovery than conventional clean energy deployment. But the upside is substantial.

“With this backing, we will work alongside industrial partners globally to move from exploration through to commercial development,” said Bart Markus, Mantle8’s chairman. “The next two years are about proving that the active hydrogen systems our technology has pinpointed can deliver sustained, commercially viable flow.”

If Mantle8 succeeds, natural hydrogen could add a new option to the clean energy mix. For Europe, it could also connect decarbonization strategy with industrial competitiveness and energy sovereignty.

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