A UK-based company combining compact spherical tokamak geometry with high-temperature superconducting magnets, pursuing what it calls the fastest path to commercial fusion energy.
Tokamak Energy was founded in 2009 as a spin-out from the Culham Centre for Fusion Energy (now UKAEA) by Alan Sykes, David Kingham, and Mikhail Gryaznevich. Headquartered at Milton Park in Oxfordshire, England, the company pursues a dual-technology strategy: compact spherical tokamaks for plasma confinement and high-temperature superconducting (HTS) magnets built from rare-earth barium copper oxide (REBCO) tape.1
The spherical tokamak—a tighter, more compact variant of the conventional tokamak—was pioneered at Culham by Sykes and colleagues beginning in the 1990s. Tokamak Energy’s thesis is that combining this geometry with HTS magnets can deliver fusion-relevant magnetic fields in a device far smaller and cheaper than ITER-scale machines.2
The company has also developed a series of HTS magnet demonstrators. Its Demo4 system—a complete set of HTS magnets arranged in a tokamak configuration—achieved magnetic field strengths of 11.8 Tesla at −243°C during 2025 testing. While impressive for an HTS system, this remains below the 20 T field strengths that the company has stated it needs for a commercial power plant, and independent benchmarking against competing HTS programs (notably Commonwealth Fusion Systems) is ongoing.3
In 2024, Tokamak Energy launched TE Magnetics, a commercial division selling HTS magnet systems to customers in medical imaging, scientific research, and industrial applications—a near-term revenue strategy while fusion development continues.
As of late 2024, the company has raised approximately $335 million in total: $275 million from private investors and $60 million from UK and US government sources. The most recent round, a $125 million raise in November 2024, was co-led by East X Ventures and Lingotto Investment Management.4
Government partnerships include a $52 million upgrade program for ST40 jointly funded by the US Department of Energy and the UK Department for Energy Security and Net Zero. In October 2025, Tokamak Energy Inc. (the US subsidiary) was selected for the DOE’s Fusion Innovative Research Engine (FIRE) Collaboratives program. The company also secured a contract from General Atomics to advance next-generation submarine power systems.5
Tokamak Energy is upgrading ST40 with lithium wall systems and RF heating while continuing HTS magnet development toward higher field strengths. The company has not publicly committed to a specific date for net energy gain or a pilot plant, distinguishing it from some competitors who have made more aggressive timeline claims. Its dual commercial strategy—near-term magnet sales and long-term fusion energy—provides a revenue path that most pure-play fusion startups lack.