Type One Energy has completed a $200 million Series B round, bringing the company’s total funding to over $400 million. The capital comes from a consortium led by Breakthrough Energy Ventures and Clutterbuck Capital, with participation from Lowercarbon Capital, Siemens Energy Ventures, and SiteGround Capital. The round has been described as the third-largest Series B in the fusion sector over the past five years.
The funds will support Project Infinity, structured across two distinct phases. The first centers on Infinity One, an engineering prototype to be built at the Tennessee Valley Authority’s Bull Run site, with a target start-up date of 2029. The second involves the development of Infinity Two, a 400 MWe commercial fusion power plant designed to power approximately 200,000 homes, with a target timeline of 2034. The company’s internal technology development program is called FusionDirect.
Type One Energy grew out of academic research at the University of Wisconsin-Madison, where co-founder David Anderson spent decades leading the Helically Symmetric eXperiment (HSX), attracting $47 million in public funding. The company was founded in 2023 and operates under what CEO Christofer Mowry calls a “partner-intensive” model: one that integrates advanced manufacturing, computational physics, and high-field superconducting magnets. Rather than a bet on a single technological variable, this is a wager on a complete industrial system.
The stellarator is an approach to magnetic plasma confinement that differs from the tokamak — geometrically more complex, but theoretically more stable under continuous operation. The technical debate between the two architectures has long remained open. Today, however, with Germany’s Wendelstein 7-X setting a record of 43 seconds of continuous plasma — and private capital beginning to flow into the field — the stellarator is gaining industrial credibility. The Fusion Industry Association has estimated that the global fusion sector raised $4.48 billion in the year through July 2026, a 69% increase over the previous year.
The involvement of Siemens Energy Ventures as an investor carries a different weight than purely financial capital: it signals that a major industrial energy player is beginning to position itself across the entire fusion value chain, from technology to plant construction and operations. If Infinity One meets its technical targets by 2029, Type One Energy will have turned decades of university research into a working prototype. The road from there to Infinity Two is still a long one — but for the first time, the trajectory has a deadline.
