US fusion startup Thea Energy has raised an oversubscribed $100m Series B funding led by US Innovative Technology Fund. Other investors who participated in the round include General Innovation Capital Partners, Linse Capital, Calm Ventures, Climate Capital, Divergent Capital, Emerald Technology Ventures, Gaingels, Idemitsu Kosan, Overlay Capital, Timescale Ventures, and What If Ventures.
The new funding will help Thea expand manufacturing for its smaller magnets and begin construction of Eos demonstration device starting next year. Thea previously closed a $20m Series A in early 2024. The new round brings total private investment to $130m.
Thea Energy specialises in magnetic confinement fusion and is developing an optimised, software-driven variation of the stellarator. The company was spun out of Princeton University and the Princeton Plasma Physics Laboratory (PPPL) in 2022 and was originally launched under the name Princeton Stellarators before rebranding to Thea Energy.
The company, headquartered in Kearny, New Jersey, was co-founded by Brian Berzin (CEO), with a background in electrical engineering and private equity, and David Gates (CTO), who previously led pioneering stellarator magnet array research at PPPL.
Stellarators have historically been considered incredibly complex because they require highly warped, three-dimensional magnetic coils to precisely shape and contain superheated plasma. Thea Energy’s unique approach completely reimagines this hardware Instead of custom-manufacturing twisted 3D magnets, Thea Energy utilises a proprietary architecture consisting of standardised stacks of uniformly flat, planar superconducting magnets.
The company relies on advanced, AI-enabled control software to dynamically program these flat magnets. By adjusting each magnet individually – similar to controlling individual pixels on a digital display – software generates the highly complex magnetic fields required to stabilise the plasma. Shifting the complexity from precision mechanical manufacturing to software makes the reactors far simpler, cheaper, and faster to mass-produce.
Thea Energy is an inaugural awardee of the US Department of Energy’s (DOE’s) Milestone-Based Fusion Development Program launched in 2022. In January, it became the first company to receive official DOE certification for its preconceptual Helios pilot plant preconceptual design under the programme, which aims to accelerate fusion commercialisation through public-private partnerships. Thea Energy was one of the first eight companies selected for support in May 2023. However, agreements were not signed with the awardees until more than a year later in June 2024.
Thea Energy is leveraging its Series B capital to build out a second manufacturing facility in Northern New Jersey. Its headquarters facility in Kearney houses a primary design lab and advanced manufacturing lines. Thea Energy uses this space to design, wind, and test its standardised planar magnets. The Kearny engineering team utilized this site to build and test over 50 generations of its full-scale planar shaping coil magnets. It is where they achieved a baseline magnetic field of over 6 Tesla.
The new facility will mass-produce and scale the assembly of the uniform shaping coils needed for planned larger reactors. Because Thea Energy’s stellarator design breaks away from unique, twisted 3D magnets in favour of standard, flat, repeatable “pixels,” the factory will function more like standardised component assembly lines than custom machine shops. This drastically simplifies the manufacturing logistics.
The new funding will also support development of Eos. Site selection for Eos is underway and construction is slated to begin in 2027, with the goal of achieving steady-state plasma operations by 2030. Helios (Commercial Power Plant) is targeted for commercial service around 2034. The company is already in active discussions with more than a dozen utility partners and hyperscale data centre operators.
