Proxima Fusion and Kyoto Fusioneering sign MoU to develop plasma heating and fuel cycle technologies for commercial fusion plants
German startup Proxima Fusion and Japan’s Kyoto Fusioneering signed a Memorandum of Understanding in Tokyo on October 28, 2026, to jointly develop two of the most critical technologies needed to run a commercial fusion power plant: plasma heating systems based on next-generation gyrotrons, and fusion fuel cycle technologies.
The agreement, formalized during German Chancellor Merz’s visit to Japan, pairs Europe’s leading stellarator company with one of the world’s foremost fusion technology providers — with the stated goal of advancing the industrial supply chain behind commercial fusion energy.
MoU signed in Tokyo during Chancellor Merz’s visit
The timing wasn’t a coincidence. Chancellor Friedrich Merz was in Tokyo on an official state visit, and the two companies chose that diplomatic moment to make it official. The backdrop gave the agreement real weight — a signal that fusion energy isn’t just a scientific ambition anymore. It’s becoming a matter of industrial and foreign policy.
If Alpha succeeds, the path leads to Stellaris, Proxima’s first commercial fusion power plant, which the company aims to have operating later in the 2030s.
Under the MoU, Proxima and Kyoto Fusioneering will expand their joint work across two fronts: next-generation gyrotrons for plasma heating, and fusion fuel cycle technologies. Both are essential to running a commercial fusion plant. Without systems capable of heating plasma to the extreme temperatures fusion requires — and without a reliable cycle to manage hydrogen isotope fuel — no plant can operate at all.
Kyoto Fusioneering will also bring its technologies and engineering expertise directly into fusion commercialization efforts in Germany, including engagement with the national Fusion Hubs initiative, overseen by Germany’s Federal Ministry of Research, Technology and Space.
Why the partnership was formed
Germany has made a bold bet. The federal government has set an explicit goal: build the world’s first fusion power plant on German soil. That ambition puts enormous pressure on the country’s industrial ecosystem to develop components that, in many cases, don’t yet exist at commercial scale anywhere in the world.
Proxima has been assembling supply chain partnerships to close that gap. Existing agreements already cover high-temperature superconducting magnets — a core part of its stellarator design — but plasma heating and fuel cycle systems remained open items. This MoU fills them.
Kyoto Fusioneering brings something Germany’s industrial base currently lacks: decades of hands-on fusion engineering experience. The company has deep expertise in plasma heating systems, tritium fuel cycle management, and blanket systems — the components that both breed tritium fuel and extract heat from the fusion reaction. That expertise sits alongside Germany’s world-leading stellarator research tradition rather than duplicating it.
Japan and Germany are both advanced manufacturing economies with strong research institutions. Combining Japan’s fusion engineering track record with Germany’s stellarator leadership creates something neither country could pull off independently — which is precisely the logic driving the deal.
Expected outcomes and project milestones
The MoU is structured around a specific roadmap. Proxima’s next major milestone is Alpha, a demonstration stellarator it plans to have operating in the early 2030s — designed to prove that net-energy fusion is achievable in a stellarator configuration, a critical step before anyone builds a commercial plant.
If Alpha succeeds, the path leads to Stellaris, Proxima’s first commercial fusion power plant, which the company aims to have operating later in the 2030s. Kyoto Fusioneering’s plasma heating and fuel cycle technologies would be essential to both machines.
Bringing proven engineering capabilities into Germany’s Fusion Hubs network could meaningfully accelerate its development. That program, run by the Federal Ministry of Research, Technology and Space, is designed to connect research institutions, startups, and industrial suppliers into a coherent national fusion ecosystem. The collaboration is expected to deepen industrial ties between Japan and Germany in the fusion sector well beyond any single project.
Background: The two companies and the broader fusion landscape
Proxima Fusion was founded as the first spin-out from the Max Planck Institute for Plasma Physics. Its stellarator design builds on scientific results from the Wendelstein 7-X program, one of the most advanced stellarator experiments ever built, and the company now employs around 200 people across offices in Munich, Zurich, and Oxford.
Its Alpha Alliance — a consortium of more than 50 industrial partners — supports the commercial stellarator program across engineering, manufacturing, and supply chain development. The MoU with Kyoto Fusioneering adds another significant partner to that network.
Kyoto Fusioneering operates globally, with a presence in Japan, Germany, the UK, the US, and Canada. The company describes itself as a fusion technology and integrated systems developer, covering plasma heating, tritium fuel cycle, and tritium breeding blanket systems. Its technologies are designed to work across different fusion confinement approaches, which makes it a versatile partner for the broader industry — not just for stellarator programs.
What this agreement means for Fusion’s commercial future
Two companies. Two countries. One shared goal: turning fusion science into a functioning industry.
The MoU between Proxima Fusion and Kyoto Fusioneering covers plasma heating via next-generation gyrotrons and fusion fuel cycle technologies — both essential to any commercial fusion plant. It supports Proxima’s roadmap toward the Alpha demonstrator in the early 2030s and, eventually, the Stellaris commercial plant. Kyoto Fusioneering gains a direct connection to Germany’s national Fusion Hubs initiative, while industrial ties between Japan and Germany deepen at a moment when governments worldwide are accelerating their fusion programs.
The supply chains for commercial fusion don’t fully exist yet. Partnerships like this one are how they get built.
Kelly is an experienced writer with 15 years of experience exploring the big stories that shape our world, from tech breakthroughs and space exploration to climate, energy, and the fascinating quirks of science. She has a talent for turning complex ideas into sharp, memorable insights that stay with readers long after they’ve finished reading.
