Max Planck spinout nets €20M to build ‘stellarator’ fusion machine


A German startup has secured new funding for a peculiar twisted-looking reactor that could prove a quicker path to clean, virtually limitless fusion energy. 

Proxima Fusion has raised €20mn as it looks to bring its designs for the so-called stellarator fusion reactor to life. 

“We are working to deliver a demonstrator of net-energy production in continuous operation by 2031, and a first-of-a-kind power plant in the mid-2030s,” Dr Francesco Sciortino, CEO and co-founder of Proxima Fusion, told TNW via email.

Much like the more well-known tokamak, a stellarator confines plasma using giant magnets. But instead of generating electric currents inside the plasma, stellarators use external coils to make a twisting magnetic field. 

Huge electromagnets outside the plasma chamber give stellarators their bizarre shape. Tokamaks look more like a doughnut.  

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Stellarators have several advantages over tokamaks. They need less power to operate and make the plasma easier to control. Tokamaks are better at keeping plasma hot. But stellarators are better at keeping it stable. This stability is critical for a viable fusion energy plant. 

The biggest drawback is complexity. Stellarators are notoriously hard to design and build. This is why they were largely set aside in the 1960s for their simpler cousin, the tokamak. 

However, advances in computational power are closing the gap.  

AI-enabled fusion design

“Simulation-driven engineering has been a key feature of Proxima Fusion since its inception,” said the company’s co-founder Martin Kubie. “Now, AI-enabled design has taken the centre stage.”

AI lets engineers simulate plasma’s behaviour in ways that weren’t previously possible. Instead of building thousands of reactors and hoping they will work, AI-powered supercomputers allow scientists to run countless simulations before arriving at a winning design.

“Proxima Fusion is strong in automated design, AI engineering, and high-temperature superconducting magnets. These strengths give us unwavering confidence in their ability to make steady-state fusion energy real,” said Benjamin Erhart. He is a general partner at UVC Partners, one of the startup’s investors. 

fusion stellarator machine