Europe’s Largest Private Fusion Raise

This past week, Munich-based Proxima Fusion announced €130 million ($150 million) in Series A funding, the largest private fusion round in European history. Co-led by Cherry Ventures and Balderton Capital, the raise brings Proxima’s total funding to over €185 million ($200 million) as it pushes toward a commercial stellarator power plant.

Founded in 2023 as a spinout from the Max Planck Institute for Plasma Physics (IPP), Proxima retains close ties with the Wendelstein 7-X team and other European labs. The company’s stated goal is to build the first commercial-scale stellarator by the 2030s.

W7-X and the End of the Physics Debate

Stellarators have long been regarded as scientifically sound but commercially implausible. Their complex magnet geometries made them difficult to design, expensive to build, and almost impossible to scale, at least with conventional tools and materials.

That narrative is beginning to shift. A key driver has been the success of the Wendelstein 7-X program, which arguably retired the core physics risks of the quasi-isodynamic stellarator.

A landmark paper in Nature confirmed that experimental results closely matched simulations, proving that the machine’s contorted magnetic fields work as designed. That proof point gave stellarators something they had previously lacked: credibility not just in theory, but in operation.

However, W7-X is a research machine, not a power plant. Translating that performance to a commercial reactor still requires solving engineering problems that no one has yet tackled at scale.

Proxima’s Approach

Proxima believes it has those solutions, and its pitch rests on two technology levers:

• Advanced simulation: AI-accelerated design tools now allow faster, more precise optimization of magnetic configurations. Iterations that once took years now take days.
  

• High-temperature superconductors (HTS): These materials enable higher magnetic field strengths in smaller volumes, potentially reducing reactor footprint and lowering costs.

Yet despite these advancements, HTS coil fabrication at scale remains largely unproven. Even Commonwealth Fusion’s landmark demo was a single coil, not an integrated magnet system.

Proxima is betting it can bridge that gap, with two major technical milestones planned over the next six years:

• Stellarator model coil (by 2027): A prototype HTS coil to de-risk key aspects of field quality, manufacturability, and mechanical tolerance.
  

• Alpha demo plant (by 2031): A full demonstration stellarator targeting net energy (Q > 1) in steady-state operation.

If the Alpha performs as promised, it would be the first stellarator to produce continuous net power. But 2031 is an aggressive timeline for a machine of this complexity, and it’s worth noting that no stellarator company has yet demonstrated hardware outside of basic component prototyping.

Shifting Strategies and Regional Dynamics

Investors seem to be comfortable with the risk, and Proxima’s raise was oversubscribed. It’s part of a broader trend: investors are evaluating fusion startups with a more critical eye, and capital is concentrating around more technically validated approaches.

The round also reflects regional dynamics. Led by European VCs, Proxima’s raise aligns with the EU’s push for strategic energy independence. Germany in particular, now fully nuclear-free on the fission side, intends to build the world’s first fusion power plants, backed by cross-party political support and significant public sector funding. Policy support and research infrastructure make Europe one of the few places where a stellarator pilot may find a viable path to deployment.

An Increasingly Crowded Field

Proxima isn’t alone in the stellarator race. Type One Energy is preparing its “Infinity One” prototype for construction at a site in Tennessee. Renaissance Fusion is developing simplified cylindrical magnets and a novel liquid-metal wall. All three are targeting pilot plants in the early 2030s.

Based on comments made by Type One CEO Christofer Mowry when we last spoke, I expect a fundraise from Type One in the coming months. If that materializes, Proxima might find itself with some well-funded competition.

If even one of these companies demonstrates a working stellarator with net energy output and a repeatable path to scaled manufacturing, the field could shift significantly. And that’s a good thing: the more viable approaches under development, the better the odds that at least one can find success on a commercial scale.