Mantle8, a French cleantech company focused on natural hydrogen exploration, has closed a €31 million Series A funding round to advance its drilling campaigns and subsurface assessment activities. The round, led by Sandwater, brings the company’s total capital raised to €37 million, equivalent to approximately $44 million.
The funding round included participation from a consortium of established investors spanning Europe and the climate tech sector. Breakthrough Energy Ventures, the climate-focused investment fund backed by Bill Gates and other prominent figures, joined the round alongside French institutional investors Bpifrance and IP Group. Wind Capital also participated in the financing.
Based in Grenoble, a region known for its technological innovation and clean energy focus, Mantle8 is developing capabilities to identify and extract natural hydrogen from subsurface reserves. Natural hydrogen, also referred to as white or gold hydrogen, has emerged as an area of growing interest within the energy transition landscape, offering potential as a zero-carbon fuel source without the emissions associated with conventional hydrogen production methods.
The company intends to deploy the newly secured capital toward expanding its natural hydrogen exploration operations and conducting drilling campaigns to assess the viability and scale of identified hydrogen deposits. This represents a significant step in Mantle8’s development as it transitions from the exploration phase toward more capital-intensive drilling and evaluation activities.
The participation of Breakthrough Energy Ventures signals institutional validation for the natural hydrogen sector, which remains relatively nascent compared to other cleantech solutions. The fund has previously backed companies working across decarbonization technologies including direct air capture, sustainable materials, and alternative energy sources. Bpifrance’s involvement reflects French government support for domestic innovation in clean energy technologies, while IP Group’s participation adds expertise in technology commercialization and scaling.
Mantle8’s funding success comes amid broader European interest in diversified hydrogen production methods. While electrochemical hydrogen production using renewable electricity has dominated recent investment activity, natural hydrogen represents an alternative pathway that does not require energy input for production, potentially offering economic advantages at scale if reserves prove commercially viable.
The funding also reflects investor confidence in the French startup ecosystem’s ability to develop frontier cleantech solutions. Grenoble has established itself as a hub for deep tech and cleantech ventures, benefiting from proximity to research institutions and existing industrial infrastructure related to energy and materials science.
The natural hydrogen sector remains in early stages, with significant technical and commercial questions still to be resolved. Mantle8’s Series A funding positions the company to address key uncertainties through field exploration and data collection, which will inform the broader industry’s understanding of natural hydrogen’s potential contribution to European decarbonization objectives.
As European nations work toward net-zero emissions targets, investors and policymakers are increasingly supporting exploration of multiple hydrogen pathways, viewing technological diversity as essential to achieving climate goals while maintaining energy security.