As the world races to add more power plants to satiate AI’s thirst for electricity, investors have been plowing money into nuclear fusion, the pie-in-the-sky technology that appears to be inching its way toward commercial viability.

The latest exhibit: Tokamak Energya UK-based startup that’s working to refine its squeezed-doughnut approach to fusion power. The company announced Tuesday that it had raised $125 million to continue development of the reactor design and expand its TE Magnetics division.

Tokamak Energy has been working on fusion since 2009, when it was spun out from the UK Atomic Energy Authority. The startup is pursuing what’s known as magnetic confinement fusion, which uses magnets to corral searing-hot plasma inside a reactor. This forces the plasma into a doughnut shape, but unlike other approaches, Tokamak Energy’s spherical tokamak takes that doughnut and squeezes it at the circumference. Its ST40 prototype generated a record-setting 100 million degree C plasma in 2022.

Tokamak Energy is aiming to operate a pilot power plant starting by 2034, the Telegraph reportedwhich puts it approximately on par with several other fusion startups, though several years behind frontrunners like Commonwealth Fusion Systems.

To help bridge the gap until commercial fusion revenue rolls in, Tokamak Energy launched a division, TE Magneticsto sell its expertise in high-temperature superconducting magnets, a business model that’s becoming more widespread among fusion startups.

The company has raised a total $275 million from private investors, including this week’s raise, which was led by East X Ventures and Lingotto Investment Management, which manages the Agnelli family fortune, with participation from British Patient Capital, BW Group, Furukawa Electric Company, and Sabanci Climate Ventures.