Proxima Fusion, a Munich-based developer of quasi-isodynamic stellarator fusion power plants, has raised €411 million ($468M) at a €2.4 billion valuation. The round, the largest private investment in European fusion history, was led by XTX Ventures and East X Ventures with strategic participation from RWE and Google. The capital will accelerate development of the Alpha net-energy demonstration stellarator and the Stellaris commercial power plant concept.
Stellarator Approach Gains Validation
The timing aligns with a broader shift toward stellarators as a viable commercial path. Type One Energy pivoted from quasi-symmetry to the same quasi-isodynamic approach Proxima uses. Commonwealth Fusion Systems raised $863M Series B2 in August 2025, while Helion Energy secured $465M Series G in June 2026. Proxima's design emphasizes steady-state operation without the disruption risks inherent in tokamaks.
Surging Demand for Baseload Power
AI data centers are projected to drive global electricity consumption to over 500 TWh by 2026. Existing clean energy sources struggle to deliver reliable 24/7 carbon-free power at the scale required by hyperscalers. Current fusion concepts face either plasma instability or manufacturing complexity that has delayed commercialization for decades.
QI Stellarators Enable Continuous Operation
Proxima combines Wendelstein 7-X research heritage with high-temperature superconducting magnets and AI-driven optimization through its StarFinder platform. The Stellaris concept, published in Fusion Engineering and Design, integrates all major physics and engineering constraints into a single peer-reviewed design. Unlike tokamaks, the stellarator configuration operates continuously without current-driven instabilities.
"We are no longer asking if fusion works – we are asking how fast we can build it."
Mission Capital and Strategic Backers
The round brings together growth investors XTX and East X alongside strategic players RWE and Google. RWE provides site access at the former Gundremmingen nuclear plant, while Google's participation signals validation of fusion as a solution for AI energy demand. Total capital secured now exceeds €650 million.
European Fusion Market Heats Up
The nuclear fusion market is forecast to reach $33.77 billion by 2031 according to MarketsandMarkets. Thea Energy raised $100M Series B in May 2026, and Marvel Fusion secured over $400 million. Government support in Germany includes a €2 billion national fusion action plan and €400 million in Bavarian backing for Proxima's test facility.
Leadership with Hardware Scale-Up Experience
Co-founder and CTO Barrington D'Arcy previously led production scaling at SpaceX. Chief Engineer Martin Kubie joined from McLaren F1 and Google X. The team has grown to nearly 200 people across Munich, Zurich, and Oxford in under three years.
Alpha and Stellaris Roadmaps Advance
With the new funding, Proxima plans to complete its Stellarator Model Coil demonstration in 2027 and begin Alpha operations targeting net energy in 2031. The first commercial Stellaris plant is targeted for the Gundremmingen site in Bavaria.