Proxima Fusion Stellarator Dream: Building the First Commercial Stellarator Power Plant

Episode overview

In this first episode, Dr Ben Miles explores Proxima Fusion, a Max Planck Institute spinout, and their plan to commercialize stellarator fusion. The video breaks down why fusion is so hard, how stellarators confine hot plasma without pulsing, and why Proxima is betting on a high field magnet approach to scale up from the Wendelstein 7X design.

• Clear explanation of the triple product of fusion and magnetic confinement
• Comparison of stellarator and tokamak approaches and why the twist matters
• Proxima's strategy to raise high field magnets using REBCO tapes
• Roadmap to Alfa and Stellaris with Bavarian partners and a multi‑billion euro vision

Introduction and context

This video follows Dr Ben Miles as he sits down with Proxima Fusion co founder Francesco to understand why they are betting on a stellarator path for commercial fusion energy. Proxima, a spinout from the Max Planck Institute, has raised hundreds of millions of euros from major backers including Google and RWE, making it the best funded fusion effort in Europe. The aim is to translate decades of stellarator physics into a power plant that can deliver net energy and decarbonized electricity at scale.

Fusion physics primer

The host walks through how fusion works at a physical level and the three simultaneous requirements known as the triple product hot, dense, and contained for long enough. To reach the necessary temperatures, hydrogen must be heated to tens of millions of degrees, creating plasma. Because no material can withstand contact with such temperatures, magnetic confinement is used. The video explains how magnetic fields bend charged particle paths into spirals, and how a well designed magnetic geometry keeps ions on track without building up a damaging capacitor that could push plasma to the reactor walls.

Stellarator history and design challenges

The narrative then traces the history from Lyman Spitzer’s original stellarator concept through model A, B, and C, and explains why the early designs leaked plasma. The fundamental issue was coil tolerances; even tiny imperfections could cause leaks. The video contrasts this with the tokamak breakthrough of the Soviet T3 which used a simple torus with a central solenoid and a current in the plasma to create a helical field, solving the drift problem but creating an energy penalty due to ramping and pulsing operation.

Wendelstein 7X and computational optimization

Computing power enabled a new approach: optimizing the stellarator geometry to cancel drifts. The Planck Institute’s W7X demonstrated nested magnetic surfaces and quasi isodynamic optimization, achieving stable plasma confinement for the first time. It showed the physics could work, though it is a physics demonstrator rather than a net energy device, and uses hydrogen and helium rather than fusion fuels like deuterium and tritium.

Proxima’s engineering strategy

Proxima’s core idea is to scale up the magnetic field power by upgrading magnets. They target REBCO based superconducting tapes to achieve higher fields and thus much higher potential fusion power from the same plasma volume. The discussion includes how REBCO tapes can be made into flexible, high current cables using Hastelloy substrates, and why this is a significant engineering challenge requiring new manufacturing and cryogenic capabilities.

Roadmap and funding

The video outlines a multi‑phase plan with a memorandum of understanding between the Free State of Bavaria, RWE, and the Max Planck Institute. The immediate goal is to test a Stellarator model coil in 2027, de‑risk the technology, then move to Alfa a demonstration stellarator in the early 2030s, with Stellaris envisioned as the eventual power plant. Bavaria would contribute up to 400 million euros, with further funding sought from the German federal government and other sources. The speaker emphasizes that fusion power would become a platform for decarbonized electricity, high‑temperature industrial heat, and a domestic cryogenics and superconducting magnet supply chain, potentially revolutionizing energy infrastructure by the 2040s and beyond.