The lithium will arrive first, then the upgraded heating systems. By 2027, if all goes according to plan, Tokamak Energy's ST40 reactor—a gleaming spherical tokamak tucked away in Oxfordshire—will be running experiments that the company's founders scarcely imagined possible when they spun out from Britain's atomic energy authority 15 years ago.
On December 5, the Oxford-based fusion startup announced it had secured $52 million in a trilateral partnership that splits the bill three ways: the U.S. Department of Energy, the U.K.'s Department for Energy Security and Net Zero, and Tokamak Energy itself, each contributing roughly $17.3 million. It's not a venture round, exactly. Think of it more as a cost-shared facility upgrade with geopolitical overtones—the first joint project under a U.S.-UK fusion strategic partnership inked in late 2023.
For Tokamak Energy, which has been methodically raising capital and hitting technical milestones since 2009, the deal represents something rarer than money: institutional validation. The fusion sector has always demanded patience, deep pockets, and an appetite for risk that venture capitalists traditionally reserve for software, not hardware that mimics the sun. Yet here are two governments betting alongside private investors that spherical tokamaks—a compact, high-performance reactor design—might crack the code on commercial fusion sooner than the big, hulking machines that have dominated the field for decades.
Inside the Upgrade
The five-year program will retrofit the ST40, already valued north of $100 million by the DOE, with a lithium-coated inner wall designed to improve plasma confinement. Princeton Plasma Physics Laboratory will lend its lithium-coating expertise; Oak Ridge National Laboratory will assist with pellet fueling capabilities. The technical jargon obscures what's actually at stake: plasma-facing components that can withstand the punishing conditions inside a fusion reactor are critical bottlenecks. Solve that, and you're one step closer to a machine that produces more energy than it consumes.
The upgraded facility should be operational by 2027, accessible to universities and national labs across both countries—a point the DOE emphasized repeatedly in its announcement. Collaboration, after all, has become the watchword in fusion circles, even as private companies like Tokamak Energy compete for funding and talent.
Late last month, the company took delivery of a 1-megawatt gyrotron from Kyoto Fusioneering, a Japanese supplier making inroads in the fusion hardware market. Installation is slated for sometime in 2025. The device will provide radio-frequency heating to push plasma performance higher, edging Tokamak Energy closer to its ultimate goal: demonstrating net electricity generation, the holy grail that has eluded fusion physicists since the 1950s.
A Funding Drumbeat
The government partnership comes on the heels of a $125 million private financing round announced just weeks earlier in November. That raise, co-led by East X Ventures and Lingotto Investment Management, brought in a roster of new backers: Furukawa Electric, British Patient Capital, BW Group, and Sabanci Climate Ventures. British Patient Capital chipped in £8 million through its Future Fund: Breakthrough program, a government-backed initiative aimed at moonshot technologies.
Since 2009, Tokamak Energy has raised $335 million—$275 million from private investors, $60 million in public funding. The company now employs more than 260 people, holds 77 families of patent applications (mostly centered on high-temperature superconducting magnets and spherical tokamak designs), and operates out of facilities that blend academic rigor with startup urgency.
In 2022, the ST40 device achieved ion temperatures exceeding 100 million degrees Celsius, a commercially relevant threshold and, at the time, the highest triple product recorded by a private fusion company. The results were peer-reviewed and published in Nuclear Fusion the following year—a deliberate move by a company eager to prove it wasn't just another well-funded science project with vague promises.
"We're not here to build a demo and walk away," CEO Warrick Matthews told industry observers when he joined from Rolls-Royce in 2023. Matthews, a veteran of aerospace engineering, brought operational discipline to a company that had spent its first decade in pure R&D mode. The pivot toward commercialization has been gradual, perhaps more calculated than some investors would like, but it's visible.
The Road to 2030-Something
Tokamak Energy is targeting commercial deployment in the 2030s, a timeline that industry insiders regard with equal parts optimism and skepticism. The company is one of eight awardees under the DOE's Milestone-Based Fusion Development Program, part of the agency's "Bold Decadal Vision" initiative authorized for up to $415 million through fiscal year 2027. Meeting milestones unlocks tranches of funding—a structure designed to reward progress, not promises.
Next up: ST80-HTS, a demonstration device that will test higher magnetic fields and longer plasma pulses. After that comes ST-E1, a pilot plant concept designed to deliver around 85 megawatts of net electricity. Mid-2030s is the target, according to company materials, though anyone who's followed fusion long enough knows that timelines tend to drift rightward.
Still, there's momentum. Beyond fusion energy, Tokamak Energy operates TE Magnetics, a division commercializing high-temperature superconducting magnet technology for applications that have nothing to do with power generation. Defense contracts, including a DARPA program exploring submarine propulsion, provide near-term revenue. In September 2024, the company acquired Ridgway Machines to scale manufacturing capacity for superconducting components—an unsexy but essential step toward industrializing what has been, until recently, a lab-bound technology.
A Signal, Not a Guarantee
The $52 million program begins this year, with funding contingent on annual appropriations and milestone progress. That's Washington-speak for "we reserve the right to pull the plug," but it's also standard practice for government-backed R&D. What's unusual is the trilateral structure. Fusion has historically been an international endeavor—ITER, the massive experimental reactor in France, involves 35 countries—but this partnership reflects a narrower, more strategic alignment between the U.S. and U.K. as both nations jostle for leadership in next-generation energy technologies.
For Tokamak Energy, the deal signals something else: that spherical tokamaks, once considered an interesting but marginal approach, are now serious contenders in the race to commercial fusion. The company's compact design allows for faster iteration and potentially lower capital costs than traditional tokamaks. Whether that translates into a working power plant by the mid-2030s remains an open question.
But in a sector accustomed to decades-long timelines and technical setbacks, $52 million in government backing—split three ways, sure, but still—suggests that someone, somewhere, thinks the odds have improved.
