Google backs Proxima Fusion in €411 million raise for Europe's first fusion power plant

German nuclear fusion startup Proxima Fusion has closed a €411 million (~$468 million) financing round at a €2.5 billion valuation, with Google joining as a strategic investor alongside German energy giant RWE and a consortium of European backers.

The round marks Google's first fusion investment in Europe. The company had previously backed Massachusetts-based Commonwealth Fusion Systems, which uses a different reactor design. Google's entry signals that big tech's interest in fusion — driven by the prospect of abundant, carbon-free baseload electricity — is expanding beyond US borders.

The stellarator approach

Proxima develops stellarators, not tokamaks. Most fusion companies, including Commonwealth Fusion and ITER, pursue the tokamak design, where a plasma ring is maintained using a combination of external magnets and a plasma-driven current. Stellarators rely entirely on external magnetic coils shaped to hold the plasma in a twisted configuration, making them inherently more stable and capable of continuous operation — but historically much harder to engineer precisely enough to work at scale.

Proxima's bet is that modern AI-driven engineering tools and advanced manufacturing make high-precision stellarator design tractable for the first time. The company has 200 employees across Munich, Zurich, and Oxford.

The funding and what it pays for

The round was led by XTX Ventures and East X Ventures, with Google, RWE, SKion, KfW (Germany's state development bank), SPRIN-D, and Burda Principal Partners also participating. Existing backers UVC Partners, Cherry Ventures, Plural, and Balderton contributed. Proxima has now raised more than €650 million in total, including €95 million in public grants.

The new capital goes toward Alpha, a €2 billion demonstration stellarator. Bavaria's state government has already committed €400 million, bringing confirmed funding to €800 million. Proxima is seeking an additional €1.2 billion from the German federal government, with a decision expected later in 2026.

Timeline

Alpha is targeted for completion in the early 2030s. If the demonstration succeeds, Proxima and RWE plan to build the first commercial plant at the site of Bavaria's former Gundremmingen nuclear facility — targeting operation in the mid-2030s.

Whether those timelines hold will depend not just on engineering progress but on Germany's federal funding decision, which makes the next €1.2 billion grant application one of the more consequential near-term milestones for the European fusion sector.

As reported by Sifted, the round brings Proxima's total funding to over €1 billion when including previous capital and public grants.