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DOE Partners with UK’s DESNZ and Tokamak Energy Ltd. to Accelerate Fusion Energy Development through a $52M Upgrade to the Privately Owned ST40 Facility

US and UK governments strengthen ties by partnering with the private fusion sector to advance the development of fusion energy towards demonstration.

The U.S. Department of Energy (DOE), the U.K.’s Department of Energy Security and Net Zero (DESNZ), and the private fusion company Tokamak Energy Ltd. (TE) today announced a plan to jointly sponsor a $52 million upgrade to the ST40 experimental fusion facility to advance fusion science and technology needed to deliver a future fusion pilot plant. Fusion powers the sun and stars, and, if harnessed on Earth, could provide an abundant, safe, and carbon-emissions-free energy source. This collaboration was selected through the 2025 fiscal year Office of Science open funding opportunity.

In December 2023, the DOE and DESNZ announced a fusion strategic partnership to advance both the U.S. Bold Decadal Vision for Commercial Fusion Energy and the UK’s Fusion Strategy. A major goal of the partnership is to establish shared access to and development of facilities needed for fusion research and development (R&D). Through the DOE-DESNZ-TE collaboration, researchers at universities, national laboratories, and institutes in both the U.S. and U.K. will be able to benefit from the research carried out on the privately owned ST40 spherical tokamak. TE is one of eight awardees of DOE’s Milestone-Based Fusion Development Program, where DOE partners with the private sector to advance R&D toward realizing industry-led designs for a fusion pilot plant.

“This represents a huge leverage opportunity for advancing fusion science and technology,” said Geraldine Richmond, DOE Under Secretary for Science and Innovation. “These new investments will strengthen our partnerships with the private sector and our international allies. Each partner stands to gain significantly more than the funds committed.” The ST40 facility, valued at over $100 million, is an existing asset that neither the U.S. nor U.K. governments funded to build or operate.

“Our high field spherical tokamak ST40 has achieved impressive results in recent years, and we are thrilled to commence ST40’s new mission through this strong public private partnership. This program will advance fusion science and technology for spherical tokamaks and the industry more broadly, in pursuit of a common goal to deliver fusion power,” said Tokamak Energy CEO Warrick Matthews. The ST40 facility uses applied magnetic fields to confine plasma. Although the plasma physics of ST40 is entirely non-proprietary and published in scientific journals, TE is developing proprietary, very high-field magnets that rely on high-temperature superconductors.

Fusion requires the simultaneous achievement of three conditions within the plasma fuel: the particles must be hot enough (temperature), close enough (density), and retain their heat for long enough (energy confinement time) to release net energy. Technological advances in the confining magnets being developed by both TE and U.S.-based Commonwealth Fusion Systems (another Milestone Program awardee) are expected to enable the achievement of fusion-relevant conditions in more compact and potentially more economical devices. In a previous partnership with DOE’s Princeton Plasma Physics Laboratory (PPPL) and Oak Ridge National Laboratory (ORNL), ST40 achieved fusion-relevant temperatures hotter than the core of the sun. The goal of this work is to enable fusion conditions with good confinement that is compatible with sustainment for long durations in a future fusion pilot plant, by coating the inner wall of the ST40 device with the element lithium.

“PPPL pioneered the use of lithium coatings in fusion back in the 90s. We’ve since refined our understanding of the radical confinement improvements these coatings can enable, and we’re excited to see this expertise leveraged by and advanced in collaboration with the private fusion industry,” said PPPL Director Steven Cowley.

Both PPPL and ORNL will be assisting in the ST40 facility upgrade. PPPL will lend their expertise in lithium coatings, while ORNL will assist in deploying pellet fueling capabilities. “Our previous experience collaborating with TE on ST40 was very fruitful, and we’re happy to help strengthen the potential of this machine,” said ORNL Fusion Energy Division Director Troy Carter, who also led the development of the 2020 Fusion Energy Sciences Advisory Committee’s (FESAC) Long Range Plan (LRP). “The expansion of public-private partnerships for fusion was a key recommendation from the FESAC LRP and I’m very happy to see new programs like this implemented.”

“We’re eager to see this new capability on ST40, which will provide the U.S. a new platform for addressing key elements of the FESAC LRP and the support of commercialization of fusion energy in the U.S. with our international partners,” said DOE’s Office of Science Associate Director for Fusion Energy Sciences Jean Paul Allain. “What excites me most is the possibility of deploying our university and national lab scientists to leverage this new capability through our Private Facility Research program. It’s these publicly supported scientists, collaborating with their colleagues at private facilities, who drive the major advances needed in this field to support a competitive U.S. fusion power industry.”

“Fusion has the potential to be a clean and sustainable energy source, transforming how we power our country and countries around the world,” said Kerry McCarthy, Minister for Climate in the U.K.’s Department for Energy Security and Net Zero. “This strategic partnership between the U.K. and U.S. governments is therefore crucial to develop this new and exciting technology, and bring it into use quicker, and is a vote of confidence in the skills and expertise of those working in this innovative new field in the United Kingdom and United States.”

This collaboration is a key example of how DOE is advancing the U.S. Bold Decadal Vision by partnering with the private sector and a strategic international partner to accelerate the viability of commercial fusion energy.

The total funding of $52 million is divided evenly among all three parties (DOE, DESNZ, and TE). The project spans five years in duration, and the facility upgrade is expected to be operational in 2027. Out-year funding is contingent on congressional appropriations and satisfactory progress.