Mantle8, based in Grenoble, has completed a Series A funding round of 31 million euros. The round was led by the Norwegian investor Sandwater. Other participants include Breakthrough Energy Ventures, the Ecotechnologies 2 fund managed by the French state investment bank Bpifrance, IP Group, Wind Capital, and Calderion. According to the company, the total capital raised since its founding in 2019 amounts to 37 million euros.
Drilling campaign planned for the next two years
The capital is to be invested in an exploration and drilling campaign over the next two years. According to Mantle8, the goal is to identify the first commercially viable deposit of high-purity natural hydrogen. The company is using a specially developed technology platform to locate and assess suitable sites. Subsequently, test drilling will be used to verify volume, purity, and reservoir quality. According to the company, if successful, production costs could be around 0.80 euros per kilogram, making natural hydrogen significantly cheaper than green hydrogen from electrolysis.
Proprietary technology HOREX
The core of the technology is the multiphysics platform HOREX, with which Mantle8 claims to have completed the world's first 4D imaging of an active underground hydrogen system in early 2025. The images were created in the Hydrogeco project in the French Pyrenees. The company's exploration model, the so-called "Geological Trifecta," seeks reservoirs where an active hydrogen-generating source, continuous replenishment, and a sufficiently sealed reservoir converge.
In early 2025, Mantle8 also received a seed funding round of 3.4 million euros, led by Breakthrough Energy Ventures. This is supplemented by a grant of 2.06 million euros from the EU Just Transition Fund for the industrialization of exploration technology.
Investor voices
"This raise reflects the growing conviction among leading clean tech investors that natural hydrogen is a resource worth pursuing at scale," says Emmanuel Masini, founder and CEO of Mantle8. The existence of natural hydrogen is scientifically established, the challenge lies in finding commercially usable deposits. Bart Markus, chairman of Mantle8, adds: "The next two years are about proving that the active hydrogen systems our technology has pinpointed can deliver sustained, commercially viable flow."
