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Mon, 20 Apr 2026

Mon, 20 Apr 2026 The 'dumb machine' promising a clean energy breakthrough

A stellarator is difficult to build, but could it be the best way to make fusion energy work?
Francesco Sciortino, co-founder and CEO of Proxima Fusion, says being accused of attempting the impossible is a common challenge faced by scientists and engineers working on nuclear fusion projects. Their goal is to replicate the reaction that powers the Sun on Earth, which could provide abundant, cheap, and emission-free electricity. Fusion involves fusing hydrogen nuclei together, releasing immense energy in the process. To maintain this reaction on Earth, extremely high temperatures are needed, similar to those found on the Sun. Proxima Fusion is working on a stellarator design, which uses magnets to manipulate plasma but has a more complex shape than its rival tokamak. Sciortino believes that the stellarator's twists and turns make it easier to control the burning hot plasma compared to the tokamak design. He says a stellarator is like a "dumb machine" because once built, it can operate without much human intervention. Proxima Fusion's Alpha device will draw on decades of work done by Germany's Max Planck Institute for Plasma Physics and its stellarator, W7-X. The aim is to produce more energy than it uses to operate, with lessons learned from Alpha helping design an even more advanced device, Stellaris. However, the challenges ahead are significant. Proxima Fusion recently won €400m in funding from Bavaria and is bidding for over a billion dollars of funding from the federal government. The company must build complex magnets at high speed and cost-effectively to make the stellarator an economic proposition. Sciortino estimates that building 40 magnetic coils will take several years, but he wants Alpha operational in just three years. Proxima Fusion has built a prototype magnetic coil and plans to test it next year. In contrast, UK-based Step is developing a tokamak design, which uses powerful magnets to contain plasma. This approach benefits from a deep experimental foundation and simpler magnetic geometry, making it relatively easier and cheaper to build. However, Sciortino believes that Germany's expertise in manufacturing can help Proxima Fusion overcome the challenges ahead. The company has a strong workforce with CNC machine skills and is building a magnet factory to produce the complex magnets needed for Alpha. Once complete, Alpha will be a key step towards developing a fusion power plant. Proxima Fusion is racing against other groups working on fusion technology, but Sciortino believes that Europe can be at the forefront of this industry.