Tokamak EnergyUpgrade shutdown
Compact high-field spherical tokamak operating at the company's Oxfordshire campus since 2018 and the machine behind its plasma records. The spherical geometry confines plasma more efficiently per unit of magnetic field than a conventional tokamak, which is what makes a smaller, cheaper power plant plausible.
Latest update Aug 31, 2026
01
Closed out its 2025 campaign in December with three records (1 MA plasma current, highest stored energy, triple product up 30%+) and entered the $52M DOE/DESNZ-funded LEAPS upgrade shutdown that runs through most of 2026, including a new Rockwood Group-built high-field centre column replacing the original after more than 5,000 plasma pulses. The upgrade also adds lithium-coated all-metal plasma-facing components, an upgraded Thomson scattering diagnostic and radiofrequency heating; the gyrotron heating system passed site acceptance testing in July 2026 and the next experimental campaign is scheduled for 2027-2028.
02
03
Announced next steps from Tokamak Energy that mention ST40.
2026-2029
Execute the eight magnet work packages under the £70M STEP contract with UK Fusion Energy, covering magnets, tokamak systems and plasma integration, and use ST40 as the test bed for magnetic configurations feeding STEP's later design phases. After the company said it will not construct its own pilot plants, STEP is the flagship construction programme Tokamak Energy is attached to. The September 9, 2026 Demo4 campaign close is already feeding STEP model-coil testing.
2027-2028
Finish installing the new Rockwood Group-built centre column, lithium-coated all-metal plasma-facing components, the gyrotron radiofrequency heating system that passed site acceptance testing in July 2026, and the rest of the DOE/DESNZ-funded LEAPS upgrade package, then bring ST40 back online for the next campaign studying RF start-up and ramp-up and lower-recycling regimes. Re-verified September 17, 2026: ST40 remains in the upgrade shutdown; Tokamak Energy's latest news is the Demo4 campaign close, with no ST40 restart announced.
04
The company's high-temperature superconducting magnet business, built on REBCO tape wound in-house, sold both into fusion programmes and into non-fusion markets including power distribution, propulsion, motors and generators, and analytical science. Demo4, its 44-coil demonstration system, is the technology proof point.
Tokamak Energy's published fusion pilot-plant design, intended to show that a compact spherical tokamak with HTS magnets could deliver electricity to the grid. An 11-paper Focus Collection in Nuclear Fusion (August 2026) documented the pre-concept design; the company said in the same announcement that it will not construct the plant itself.
05
Commonwealth Fusion Systems
Compact, high-field tokamak designed to demonstrate net energy from fusion. It uses high-temperature superconducting magnets to achieve reactor-class magnetic fields in a much smaller machine, with peer-reviewed projections of roughly Q ~11 and ~140 MW of fusion power.
Commonwealth Fusion Systems
CFS' first planned grid-scale commercial fusion power plant, designed to deliver about 400 MW of clean electricity using the HTS magnet and tokamak stack proven through SPARC. The project is officially named the Fall Line Fusion Power Station and is planned for a 100-acre site at the James River Industrial Center in Chesterfield County, Virginia.
Helion Energy
7th-generation fusion prototype designed to demonstrate electricity production from fusion using Helion's pulsed magneto-inertial architecture and direct electricity recapture.
Helion Energy
First commercial fusion power plant, designed to generate 50+ MWe. Located in Malaga, Chelan County, Washington, on land leased from Chelan County PUD near Rock Island Dam. Power will be marketed by Constellation Energy to Microsoft data centers.