‘Green zerocarbon power may be a reality very soon’

Radical reactor design can harness heat produced in nuclear fusion to generate energy.

Nuclear fusion may have come a step closer after a radical new reactor design shaped like a twisted doughnut was unveiled by a task force set up by the King.

The reactor, known as a stellarator, offers new ways of controlling the white hot plasmas generated by nuclear fusion.

Fusion plasmas are 10 to 15 times hotter than the sun and would melt any known material so they have to be contained in powerful magnetic fields. But maintaining such a magnetic cage for more than a few seconds has defied science for 70 years – perhaps until now.

Chris Mowry, the chief executive of Type One Energy, says the company expects to start installing its first stellarator, Infinity One, in a disused power station in Tennessee next year.

Speaking at an event held by the fusion task force set up by the King’s Sustainable Markets Initiative, of which Mowry is also chairman, he said: “The machine will be experimental but is expected to produce more power than it consumes – opening the way to commercial development.”

The announcement, along with separate fusion reactor plans from the UK and China, signals a potential breakthrough in fusion design. It also shows that fusion is moving from a mainly scientific venture into a race to build the first commercially viable reactors. That progress caught the eye of the Sustainable Markets Initiative, set up in 2020 by the King when he was the Prince of Wales, prompting the recent creation of the task force.

“A gram of fusion fuel could release as much energy as burning 10,000kg of coal,” says

Mowry. “So you could generate the power for a 250,000 person-city for a year with only a few hundred kilogrammes of deuterium and lithium. I expect to see a commercial reactor within two decades.”

Such promises have been made before, and the target remains highly ambitious. Scientists first harnessed fusion power nearly 70 years ago when the hydrogen bomb was developed.

Controlling such reactions to produce energy has, however, proved impossible, despite the billions of pounds spent on research.

Mowry, and his UK colleagues on the fusion taskforce, believe they can solve this and other technical barriers that have always left fusion power “40 years in the future”.

Fusion uses extremely high temperatures and pressures to create helium by fusing hydrogen atoms. This process, which also fuels the sun and other stars, destroys only a tiny fraction of the atoms’ mass, converting it into huge amounts of heat energy that, if controlled, could generate low-carbon electricity.

Mowry says: “The idea is simple but modelling the physics of that process, especially the magnetic fields, is extremely complex. And to do it in three dimensions has really been beyond the power of computing until the last five or 10 years.

“What’s happened is that modern supercomputing, which was developed in the last 20 years, allows scientists to calculate the shape of one of these machines and then build it.”

Mowry’s comments reflect a wider excitement across the fusion science community around hopes for a commercially viable technology. Fusion research in the US has coincided with a resurgence of interest in the UK, too, partly linked to a burst of enthusiasm from Boris Johnson in 2019 when he was prime minister.

He announced £330m for fusion research, and told a Conservative Party conference that research at the Joint European Torus (JET) project at Culham, near Oxford, would lead to “virtually unlimited zerocarbon power”.

That was an overstatement but the research he financed has helped the UK remain a world leader with plans for a new fusion reactor, a replacement for JET. The Spherical Tokamak for Energy Production (STEP) will be built in a disused power station in West Burton, Notts. Tokamaks have a simple doughnut-shaped reactor. Some 200 have been built, generating invaluable data, but none has been able to maintain sustained fusion reactions.

Paul Methven, the chief executive of UK Industrial Fusion Solutions, which is building STEP, says it will “pave the way for commercially viable fusion and help develop the UK supply chain. He adds: “It’s a vital and exciting opportunity to lead and deliver a new