Mantle8, a Grenoble, France-based natural hydrogen exploration company, has raised €31 million in Series A funding. This round brings the company’s total funding to €37 million (US$44 million).
The round was led by Sandwater and includes Breakthrough Energy Ventures, Ecotechnologies 2 fund managed on behalf of the French government by Bpifrance, IP Group, Wind Capital and Calderion (an Audacia-backed investment platform).
Emmanuel Masini, founder and CEO of Mantle8, said, “This raise reflects the growing conviction among leading clean tech investors that natural hydrogen is a resource worth pursuing at scale. 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.”
Founded in 2019 by Emmanuel Masini, Mantle8 is on a mission to produce commercially viable natural hydrogen by 2030. According to the company, hydrogen is a crucial part of our future decarbonised industrial system; however, the importance of its role will depend on its price and origin.
Mantle8 claims that its technology for identifying commercially viable natural hydrogen reserves reduces exploration risk and cost, with economic models projecting production costs as low as €0.80/kg. This significantly contributes to a much lower average cost of clean hydrogen supply.
The company believes that this will fundamentally change the hydrogen sector’s economics and will unlock a low-carbon source of sovereign energy supply for Europe as well as other geographies. By partnering with organisations focused on drilling and exploiting target reservoirs, the technology can be rolled out quickly and at scale, says Mantle8.
The company develops proprietary subsurface modelling and exploration technologies, including HOREX®, a multiphysics platform that produces 4D images of active underground hydrogen systems.
The company’s exploration framework, the Geological Trifecta, identifies reservoirs where an active hydrogen-generating source, continuous replenishment and a sufficiently sealed reservoir converge.
“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,” said Tom Even Mortensen, founder and Managing Partner of Sandwater.
The company plans to deploy this capital during the next two years to fund the world’s most advanced natural hydrogen exploration and drilling campaign. Its technology platform will be employed across its global development pipeline to identify and rank the most promising opportunities. These sites will then be drilled to confirm natural hydrogen accumulations and to evaluate volume, purity, and reservoir quality in support of commercially viable, large-scale production, states Mantle8.
“With this backing, we will work alongside industrial partners globally to move from exploration through to commercial development. The next two years are about proving that the active hydrogen systems our technology has pinpointed can deliver sustained, commercially viable flow,” said Bart Markus, Mantle8’s chairperson.
In 2025, the company raised a €3.4 million Seed round led by Breakthrough Energy Ventures. It then went on to complete 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.
Read the orginal article: https://www.eu-startups.com/2026/05/frances-mantle8-raises-e31-million-to-fund-the-worlds-most-advanced-natural-hydrogen-exploration-and-drilling-campaign/
