Europe · Germany · Founded 2023
Proxima Fusion
Magnetic confinement — optimised stellarator
Magnetic
Deuterium-Tritium
€185M Series A (2025)
Net gain in the 2030s; Stellaris at former Gundremmingen fission site
Investor brief
Stellarator power plants on retired German fission sites
Executive Summary
Proxima Fusion is a spin-out of the Max Planck Institute for Plasma Physics (operator of Wendelstein 7-X, the world's most advanced operating stellarator). In 2025 the company raised Europe's largest fusion round (€185M Series A). In early 2026 it signed a landmark agreement with RWE, the Free State of Bavaria and Max Planck to build Stellaris — the world's first commercial stellarator power plant — on the site of the retired Gundremmingen fission plant.
Strategic Thesis
Inherit the world's best operating stellarator dataset (W7-X) and combine it with modern HTS coils and AI-driven optimisation.
The Problem
Global electricity demand is entering an unprecedented growth phase driven by AI infrastructure, data centers, transport electrification, industrial decarbonization, water desalination, and advanced manufacturing. Solar suffers intermittency, wind capacity-factor variability, natural gas carbon emissions, conventional nuclear cost and deployment speed, and batteries energy-density and duration limits. The world requires a new source of clean, dispatchable baseload energy. Fusion represents the ultimate energy source — the challenge is making it commercially practical.
Stellaris — HTS Optimised Stellarator
Proxima inherits Wendelstein 7-X's operating dataset and combines it with modern HTS coils and AI-driven coil optimisation to produce a manufacturable, steady-state stellarator power plant.
W7-X Heritage
Direct continuity with the world's best-instrumented stellarator.
HTS Magnet System
High-field HTS coils enable a much smaller stellarator than W7-X at higher performance.
Alpha Demonstrator
Engineering platform validating coil manufacture and integrated operation.
Stellaris Pilot Plant
First-of-a-kind commercial stellarator sited at Gundremmingen with RWE as utility partner.
Fuel Strategy
Deuterium-Tritium
Standard D-T fuel cycle with on-site breeding.
Product Platform
Alpha
Engineering demonstrator validating coil manufacturing and integration.
Stellaris
Commercial stellarator pilot plant at Gundremmingen.
Energy Conversion
Thermal (Rankine/Brayton)
Neutronic (D-T)
33–40% electrical
Deuterium-tritium fusion releases ~80% of its energy as 14.1 MeV neutrons, which deposit their kinetic energy in a surrounding blanket. The heat drives a conventional steam (Rankine) or supercritical-CO₂ (Brayton) turbine.
Conversion chain
- 1D-T plasma
- 214.1 MeV neutrons (80%) + 3.5 MeV alpha (20%)
- 3Neutrons → lithium-bearing blanket (heat + tritium breeding)
- 4Heat → steam/CO₂ turbine → electricity
The most thoroughly understood fusion fuel cycle, highest cross-section at achievable temperatures, and proven back-end engineering (steam turbines are 19th-century technology). Trade-offs: neutron-induced materials damage, tritium handling, ~33–40% Carnot-limited efficiency.
Economic Vision
Steady-state stellarator operation maximizes capacity factor; siting on a brownfield fission location reuses transmission, cooling and licensing infrastructure.
Vision
Stellarator fusion power across the European grid.
Mission
Build the first commercial stellarator power plant in Europe.
Engineering Bottlenecks
- HTS coil manufacturing in non-planar geometry
- Divertor heat exhaust in stellarator topology
Milestone Timeline
2024
€20M seed
2025
€185M Series A — Europe's largest fusion round
Early 2026
RWE / Bavaria / Max Planck agreement for Stellaris
The description above reflects Proxima Fusion's publicly stated technology goals, roadmap and architecture. Many elements — particularly net-energy gain at scale, advanced fuel cycles, and grid-relevant economics — remain ambitious objectives that have not yet been demonstrated commercially anywhere in the fusion industry. Forward-looking statements should be treated as engineering targets, not certainties.
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Citations & Sources
Academic & financial rigor- [01]
Stellaris physics basis
Proxima Fusion · 2025
- [02]
The Global Fusion Industry in 2025
Fusion Industry Association · Jul 2025
- [03]
Company disclosures and press releases
Proxima Fusion
- [04]
Peer-reviewed plasma physics literature
Journal of Plasma Physics / Nuclear Fusion