Proxima Fusion Signs Agreement to Build Europe's First Commercial Stellarator Power Plant at Former German Nuclear Site
Munich-based Proxima Fusion, RWE, Bavaria, and the Max Planck Institute for Plasma Physics have agreed on a two-stage, multibillion-euro roadmap to build a demonstration stellarator and a grid-connected commercial fusion plant at the decommissioned Gundremmingen reactor site.
Overview
Proxima Fusion, a Munich-based startup spun out of the Max Planck Institute for Plasma Physics (IPP) in 2023, has signed a memorandum of understanding with energy company RWE, the Free State of Bavaria, and the IPP to pursue what the partners describe as the world’s first commercial stellarator fusion power plant. The agreement, announced on February 26, 2026, lays out a two-stage development plan: a demonstration device called Alpha near Munich, followed by a grid-connected commercial plant called Stellaris at the site of RWE’s decommissioned Gundremmingen nuclear fission reactor in Bavaria, according to a Proxima Fusion press release.
The announcement is notable both for its scale and its location. Germany shut down its last nuclear fission reactors in April 2023, making it one of the only major economies to exit nuclear power entirely. Bavaria is now positioning itself as a hub for the next generation of nuclear technology through fusion, a process that produces no long-lived radioactive waste and carries no risk of meltdown.
What We Know
The Alpha demonstration stellarator will be constructed near the IPP campus in Garching, outside Munich. It is designed to be the first stellarator to demonstrate net energy gain — producing more fusion energy than the device consumes. The target is to have Alpha operational in the 2030s, at an estimated cost of two billion euros, as reported by Interesting Engineering.
The IPP will lead the plasma physics research program and define Alpha’s scientific mission, while Proxima Fusion takes responsibility for engineering, public tenders, and construction. RWE brings power plant construction and operation expertise, along with industrial supply chain networks.
The Stellaris commercial power plant is planned for the Gundremmingen site, where RWE is currently decommissioning a boiling water reactor that operated for decades. The existing grid connections and industrial infrastructure at the site make it a practical choice for a future fusion plant, though a final investment decision on Stellaris depends on Alpha’s results.
Financing follows a mixed model. Proxima Fusion intends to cover roughly 20 percent of costs through private international investors. Bavaria has indicated a potential state co-financing contribution of 20 percent, subject to federal funding. RWE has signaled willingness to participate financially as well. Federal support is being pursued under Germany’s High-Tech Agenda, and Bavaria has allocated up to 400 million euros for magnetic fusion research through its own Bavarian High-Tech Agenda, according to the press release.
Bavarian Minister-President Markus Soder stated that “Alpha alone requires two billion euros” but that “boldness and momentum are essential when developing future technologies.” Proxima Fusion CEO Francesco Sciortino called the MOU “a milestone that visibly positions the European fusion industry on the global stage.”
Proxima Fusion’s funding trajectory has accelerated rapidly. The company raised 7.5 million euros in a pre-seed round, followed by a 20 million euro seed round in April 2024 and a 130 million euro Series A in June 2025. A subsequent extension brought total funding to 200 million euros, making it the largest fusion funding round in European history, according to the Max Planck Society.
Why a Stellarator
Most fusion efforts worldwide use the tokamak design, a donut-shaped chamber that confines superheated plasma using magnetic fields generated partly by an electric current running through the plasma itself. Stellarators take a different approach: their magnetic fields are produced entirely by external coils twisted into elaborate three-dimensional shapes, eliminating the need for a plasma current.
This distinction has practical consequences. Tokamaks are susceptible to plasma disruptions — sudden losses of confinement that can damage reactor components — because the internal plasma current can become unstable. Stellarators are inherently disruption-free, which makes them better suited for the continuous, steady-state operation a commercial power plant would require.
The trade-off has historically been complexity. The coils in a stellarator must be manufactured to extraordinarily precise geometries to create the correct magnetic field shape. The IPP’s Wendelstein 7-X, the world’s largest stellarator, took nearly two decades to build and required 50 superconducting magnet coils, each with a unique shape. Proxima Fusion’s bet is that advances in computational design, high-temperature superconducting magnets, and manufacturing technology have made stellarator construction more tractable than it was when Wendelstein 7-X was designed in the 1990s.
What We Don’t Know
The MOU is a framework agreement, not a construction contract. No final investment decision has been made, and the financing structure remains partly contingent on federal government support that has not yet been secured. The two billion euro cost estimate for Alpha alone is substantial, and the full cost of the Stellaris commercial plant has not been publicly disclosed.
Whether a stellarator can achieve net energy gain remains unproven. Wendelstein 7-X has demonstrated excellent plasma confinement and set records for energy turnover in a stellarator, but it was designed as a physics experiment, not a power-producing device. Alpha would need to bridge the gap between experimental validation and energy production — a step no fusion device of any design has yet completed.
The timeline is also ambitious. Reaching operational status in the 2030s means beginning construction within the next few years, a pace that depends on regulatory approvals, supply chain readiness, and sustained political and financial support across multiple election cycles.
Analysis
The Proxima Fusion agreement arrives during a period of intensifying global activity in fusion energy. As previously reported, the first weeks of 2026 saw simultaneous milestones from Helion Energy, Commonwealth Fusion Systems, and China’s EAST tokamak. Proxima Fusion’s announcement adds a stellarator pathway to a landscape that has been dominated by tokamak-based approaches.
The choice of the Gundremmingen site carries symbolic weight. Germany’s decision to exit nuclear fission power was driven in part by public concerns about radioactive waste and accident risk — concerns that do not apply to fusion in the same way. Placing a fusion plant at a former fission site implicitly makes the case that fusion represents a fundamentally different technology, one that Germany can embrace even as it maintains its position against conventional nuclear power.
The project also tests whether European public-private partnerships can compete with the pace of fusion development in the United States, where companies like Commonwealth Fusion Systems and Helion Energy have raised billions in private capital and secured contracts with major technology companies. Proxima Fusion’s 200 million euros in total funding is modest by comparison, and the reliance on state co-financing introduces political risk that purely private ventures do not face.
Whether Alpha reaches net energy gain in the 2030s will determine not only the future of the Stellaris plant but also the viability of the stellarator concept as a commercial fusion pathway. If it succeeds, the Gundremmingen site could become the location where Germany re-enters the nuclear age — on its own terms.