Key facts
- Proxima and Fujikura will explore industrial-scale HTS tape output in Germany through a planned €140 million facility in Lower Saxony.
- Proxima hopes the Lower Saxony plant will make around 5,000 kilometers of tape a year by 2030.
- Proxima estimates its Alpha demonstrator needs around 20,000 kilometers of tape and its Stellaris station another 40,000 kilometers.
- Fujikura, a 141-year-old company with more than 50,000 employees, is a leader in making high-temperature superconducting tape.
- China placed strict export controls last year on yttrium and gadolinium, critical minerals used in HTS tape, plus five other rare earth elements.
- Proxima has raised more than €650 million in private and public funding, with Bavaria committing €400 million in public funding to its roadmap.
Proxima Fusion signed memoranda of understanding with Fujikura and Kyoto Fusioneering in Tokyo on October 28, with Japanese Prime Minister Sanae Takaichi and German Chancellor Friedrich Merz in attendance. The Fujikura agreement covers high-temperature superconducting (HTS) tape, which is wound into the magnets that confine plasma; the Kyoto Fusioneering agreement expands work on gyrotrons, the devices that heat plasma with high-power microwaves.
Under the Fujikura arrangement, Proxima will explore industrial-scale HTS tape manufacturing in Germany through a planned €140 million production facility in Lower Saxony that it hopes will make around 5,000 kilometers of tape a year by 2030. Proxima estimates it will need around 20,000 kilometers for its Alpha fusion demonstrator and another 40,000 kilometers for its planned Stellaris power station. Its reactors use HTS magnets to generate the fields that trap and stabilize plasma at 100 to 150 million degrees Celsius.
Fujikura, a 141-year-old company with more than 50,000 employees, built its reputation in optical fibers and is now a leader in manufacturing HTS tape. "They think this tape has the potential to be the next optical fibre," Proxima CEO and co-founder Francesco Sciortino told CNBC. Ann Mettler, president of Brussels-based clean-energy think tank Catalyse Europe, said Europe's supply chain is the deciding factor: "If Europe is first to develop this technology, it will give us a huge advantage, but key to that will be building the supply chain."
Few companies make HTS tape because the process is complex and costly. The tape is typically built around REBCO, or rare earth barium copper oxide, with buffer layers deposited on a metallic substrate such as Hastelloy, a roughly 1-micron superconducting layer grown on top, and silver and copper stabilizer layers. The ceramic layer is brittle, and HTS magnets are susceptible to quench, a localized loss of superconductivity that causes resistive heating and can lead to structural damage.
HTS tape manufacturing relies on yttrium and gadolinium, two critical minerals sourced mainly from China and subject to export restrictions. China accounts for about 69% of global rare earth mine output, and last year it placed strict export controls on yttrium, gadolinium and five other medium and heavy rare earth elements.
Founded in 2023 as a spin-off from the Max Planck Institute for Plasma Physics, Proxima has raised more than €650 million in private and public funding, with backers including Google and RWE, and Bavaria has committed €400 million in public funding to its roadmap. Proxima raised €411 million in July at a €2.4 billion valuation, Europe's largest fusion round on record. Its stellarator design, building on the Wendelstein 7-X research machine, shapes three-dimensional magnetic fields to confine high-temperature plasma without an internal plasma current, unlike tokamaks, which run in pulsed cycles.