Barnaby Finch
In a nondescript industrial unit on the outskirts of Cambridge, a small team of physicists and engineers is working on what could be the most significant breakthrough in energy since the splitting of the atom. Their goal: to commercialise nuclear fusion. Not in 50 years, but within a decade.
“We’re not asking for more time. We’re asking for more power,” says Dr Helen Marsh, CEO of Helion UK, the British arm of the American fusion startup. She stands before a tangle of copper coils and vacuum chambers, the heart of their prototype reactor. “The science is sound. The engineering is the challenge.”
Fusion, the process that powers the sun, has long been the holy grail of clean energy. It promises limitless, carbon-free electricity with no long-lived radioactive waste. But for decades, it has remained perpetually 30 years away. That narrative is shifting.
Helion is one of several private companies racing to commercialise fusion. Unlike the government-backed ITER project in France, which aims for a 500MW reactor by 2035, these startups are leaner, faster, and less constrained by bureaucracy. Helion’s approach uses a “field-reversed configuration” that combines aspects of both magnetic and inertial confinement. “We’re not building a bigger version of a 1950s experiment,” says Marsh. “We’re building something entirely new.”
The company has already raised over $500 million, with backing from high-profile investors including Sam Altman, the CEO of OpenAI. But the scepticism remains. “Fusion is 20 years away, and always will be,” says Professor Sir David King, a former chief scientific adviser. “The physics is extraordinary, but the materials science, the tritium breeding, the cost. It’s a monumental task.”
Helion’s UK team is focusing on one of the most critical components: the high-temperature superconducting magnets. These magnets are essential for confining plasma at 100 million degrees Celsius. “Think of it as holding a star in a magnetic bottle,” says Dr Raj Patel, a materials scientist at Helion. “If we can crack the magnet technology, we crack fusion.”
The UK government has taken notice. In 2023, it launched the Fusion Energy Strategy, committing £650 million to support the industry. The goal is to have a prototype fusion power plant by 2040. “The UK has a unique opportunity,” says Minister for Energy Efficiency and Green Finance, Lord Callanan. “We have the science, the engineering talent, and the regulatory environment. We want to be the global leader.”
But the path is fraught with risk. The UK’s own fusion research body, the UK Atomic Energy Authority, is pursuing a different design: the spherical tokamak. Its STEP reactor is on track for 2040. “We have to explore multiple pathways,” says Professor Ian Chapman, CEO of UKAEA. “It’s too soon to pick a winner.”
For Helion, time is money. Its founders promise electricity by 2028. “We’re not theorists,” says Marsh. “We’re builders. Show me the reactor that works, and I’ll show you the future.”
Outside Helion’s lab, a delivery truck idles. Inside, the team fires up the prototype for another test. The magnetic coils hum, the vacuum pumps whir. If they succeed, the noise will be deafening. If they fail, the silence will be louder.
