Two small British companies believe they are on the verge of a breakthrough that has eluded scientists for more than 60 years — to deliver clean, cheap energy by harnessing the nuclear fusion reaction that powers the sun.
The failure of sustained attempts to develop fusion power since the 1950s has left the undertaking tainted by claims it is a fool’s errand. But this has not put off investors from backing scientists working on quite different approaches at two private laboratories in Oxfordshire: Tokamak Energy and First Light Fusion.
Both have set the ambitious goal of delivering a working reactor ready for commercialisation by 2030, 10 years earlier than the nearby UK Atomic Energy Authority which runs the state-funded fusion programme.
Back in the 1950s the UKAEA built the Zeta fusion reactor, which was hailed at the time as a British technological triumph offering limitless power too cheap to meter. Zeta closed down in 1968 having failed to produce any useful energy.
However, recent technical advances have convinced investors to pump £50m into Tokamak Energy and a further £25m into First Light Fusion.
At the same time, the UKAEA is working on a new generation of fusion reactors at its Culham Science Centre, all based on the “tokamak” design that originated in the Soviet Union in the 1950s. This round reaction vessel holds the fuel — a plasma of superheated deuterium and tritium — in place with powerful magnets while raising its temperature above 100mC so that the atomic nuclei fuse and release vast amounts of energy.
UKAEA is working on the design for its next-generation, experimental reactor, known as Step (Spherical Tokamak for Energy Production), for which the government announced £220m public investment just before the general election. Boris Johnson, the prime minister, enthused about the technology during the election campaign and seemed personally committed to maintaining what he called Britain’s “global lead” in fusion research.
“The Step reactor will be an innovative plan for a commercially driven fusion power station, offering the realistic prospect of constructing a power plant by 2040,” said Ian Chapman, UKAEA chief executive.
But Oxfordshire’s private fusion companies have more ambitious schedules. Tokamak Energy, which was spun out of UKAEA in 2009 and employs 80 people in nearby Milton, is ready to take the next step after heating plasma in its SP40 reactor to 15mC. “We are on course for 100mC, the temperature at which fusion could begin, by next March,” said David Kingham, executive vice-chairman.
Tokamak Energy’s target is to actually generate fusion power by 2025 and have a commercial plant ready by 2030. “We understand that government labs need to be more cautious in their schedules,” said Mr Kingham. “We envisage having a 150MW device that we can license to people who are good at building power plants.”
First Light Fusion, spun out of Oxford university in 2011, is pioneering quite a different approach. Instead of confining the reactants within a strong magnetic field and superheating them, it aims to achieve the extreme conditions required to initiate fusion by firing a large number of small copper projectiles simultaneously at hypersonic speed into a tiny capsule containing deuterium and tritium fuel.
“While magnetic fusion is like a furnace that is always on, our projectile fusion is a pulsed process that transfers energy from each shot into liquid lithium coolant,” said Nick Hawker, First Light chief executive.
He said he expected to demonstrate early in 2020 that the system achieves fusion and aim for the holy grail, known as “gain”, which is when the reactor generates more energy than is used to spark the reaction by 2024. First Light is already working with the engineering company Mott MacDonald on a commercial reactor design, with the aim of having a fusion plant powering the grid by the early 2030s.
“I am very supportive of the private fusion companies and UKAEA is committed to working with them to help develop their technology,” said Mr Chapman. “The promise of fusion is so huge that there will always be a place for innovation in design.”
Meanwhile, the UKAEA continues to manage the country’s involvement in big international fusion projects. At Culham it hosts the Joint European Torus or JET, the world’s largest and most powerful tokamak and the focus of the EU’s fusion research programme.
JET has been operating since 1983. A highlight came in 1997 when it was fuelled with a deuterium-tritium reaction mixture and achieved a world record for fusion power of 16 megawatts in 1997, though this was less than the energy put in to heat up the plasma.
In recent years, experiments at JET have assisted the design and construction of Iter, a large-scale fusion machine with a reaction vessel 10 metres high (compared with 4.3 metres for JET) which is being built by a global consortium of governments in southern France.
Beset with delays and cost overruns — the current estimate is $22bn — Iter is now set to start operating in 2025. The schedule calls for JET to operate at least until 2024, including more runs with deuterium-tritium fuel, though this programme will depend on the UK’s post-Brexit relationship with the EU and Euratom.
Although no one knows exactly when commercial fusion power will arrive — and in what form — Mr Chapman expressed total confidence in its eventual arrival. “We will have fusion,” he said, “and Oxfordshire will be closely involved in making it happen.”