Proxima Fusion closed a €411m Series C at a €2.5bn valuation, led by XTX Ventures and East X Ventures with participation from Google, German energy company RWE, and existing investors including UVC Partners, Cherry Ventures, Plural and Balderton.

The Munich-headquartered company will use the funding to build Alpha, its €2bn demonstration stellarator scheduled for completion in the early 2030s. The device uses magnets to suspend hydrogen plasma, heating it to extreme temperatures so nuclei fuse and release energy.

Combined with €400m from the Bavarian government, Proxima now has €800m secured for Alpha. The company aims to raise the remaining €1.2bn from Germany's federal government through a grant expected to be tendered later this year.

Google's first European fusion bet

Google's investment marks its first European fusion backing, though the tech giant has previously invested in US nuclear builders including Massachusetts-based Commonwealth Fusion. Google also signed a power purchase agreement with Commonwealth earlier this year.

The company said it uses its purchasing power to "send a demand signal to the market for fusion energy" to accelerate the technology's development.

"Europe is racing with the United States and China to get to the first fusion power plant," said Francesco Sciortino, Proxima's cofounder and CEO. "Investors recognise both the urgency and the opportunity of what we're doing and are backing us to develop a generational energy technology company."

Proxima employs 200 people across Munich, Zurich and Oxford. The company has now raised €650m in total funding, including €95m in public grants.

After completing Alpha, Proxima plans to build its first commercial fusion plant in the mid-2030s. Fusion proponents argue the technology could provide limitless clean energy by recreating the process that powers the sun.