Fusion made in Germany: Proxima, Marvel Fusion and the Wendelstein 7-X legacy
Germany's fusion start-ups are betting on two very different routes: optimised stellarators and laser-driven fusion. Both build on decades of public research. What has actually been achieved so far.
Fusion power has been "thirty years away" for so long that scepticism is the default. Germany offers an interesting test of whether that is changing. The country has a deep public research base in magnetic confinement, and it now has private companies trying to turn that science into power plants. The claims deserve scrutiny, but so does the underlying progress.
The public foundation: Wendelstein 7-X
Wendelstein 7-X, operated by the Max Planck Institute for Plasma Physics (IPP) in Greifswald, is the world's most advanced stellarator. Like a tokamak, a stellarator holds hot plasma in a doughnut-shaped vacuum vessel using powerful magnetic fields. The difference is that a stellarator's twisted coils shape the field directly, rather than relying on a large current flowing through the plasma. That makes the design harder to engineer but potentially more stable for continuous operation.
On 22 May 2025, the last day of an experimental campaign, Wendelstein 7-X set a world record for the fusion triple product (density, temperature and confinement time combined) sustained over a long discharge, holding it for 43 seconds. IPP later noted that previously unpublished results from the JET tokamak in the UK reached similar levels for up to 60 seconds, so the two machines are joint leaders for sustained performance. The record is still well short of power-plant conditions, but it validated the stellarator concept at scale.
Proxima Fusion: from experiment to power plant
Proxima Fusion, headquartered in Munich with offices in Zurich and Oxford, is building directly on that legacy. Its quasi-isodynamic stellarator concept using high-temperature superconducting magnets draws on the scientific results of the Wendelstein 7-X programme.
The company's plan has two steps. First comes Alpha, described as a net-energy stellarator demonstrator near Munich, targeted for the early 2030s and led by Proxima together with the state of Bavaria, IPP and the utility RWE. Then comes Stellaris, a commercial power plant planned for later in the 2030s. RWE intends to build it at Gundremmingen in Bavaria, on the site of a former nuclear fission plant, a symbolic choice in a country that closed its last reactors in 2023.
In July 2026 Proxima announced a funding round of 411 million euros, according to the company, with RWE and Google joining as strategic investors. It has also formed an "Alpha Alliance" of European industrial companies to supply the demonstrator.
Marvel Fusion: the laser route
Marvel Fusion, also based in Munich, pursues an entirely different approach. Rather than confining plasma magnetically for long periods, laser fusion uses extremely short, intense laser pulses to trigger fusion in a tiny fuel target. Marvel Fusion's concept relies on nanostructured targets and short-pulse lasers, an approach that could in principle draw on the industrial laser supply chain.
The company has partnered with Colorado State University to build a high-power laser research facility in the United States. In Germany, it is a co-founder and co-owner, with the company Focused Energy, of a Laser Fusion Hub announced in July 2026. According to Marvel Fusion, the hub received funding from the Federal Ministry for Research, Technology and Space under its "Hubs for Fusion" programme. Its main campus is centred on the European XFEL in the Hamburg and Schleswig-Holstein region, with a second site at the Fusion Industrialization Campus in Biblis, Hesse. Partners include DESY, the European XFEL and the universities of Hamburg, Kiel and Rostock.
Two routes, different risks
The two approaches carry different technical bets. Stellarators rely on an enormously complex magnet geometry, which modern computing has made far easier to optimise, and on superconducting magnets that must be built to tight tolerances at scale. Laser fusion depends on lasers that fire efficiently and repeatedly, and on targets that can be manufactured cheaply in huge numbers. In both cases, the question for a power plant is not just whether fusion occurs but whether it can be sustained, maintained and paid for.
Why Germany is a plausible place for this
- Research depth: IPP, the Helmholtz centres and university physics groups provide people and facilities.
- Industrial suppliers: superconducting magnets, vacuum technology, lasers and precision engineering are established German strengths.
- Policy support: federal and state governments have created dedicated fusion funding lines.
- Utilities as partners: RWE's involvement signals that at least one large energy company sees an option worth holding.
A sober reading
None of these companies has yet produced net energy, and timelines in fusion have a habit of slipping. The physics and engineering challenges, from materials that survive neutron bombardment to reliable tritium handling, remain large. Still, the shift is real. Germany's fusion effort is no longer confined to laboratories; it now includes companies with concrete sites, named partners and hardware milestones. That makes progress easier to measure, and failure harder to hide, which is healthy for a field that has suffered from vague promises.