About half an hour into explaining how fusion energy might just change the world, Scott Krisiloff, business chief at Helion Energy, held up his water bottle to the camera. “A bottle of heavy water this size,” he said, “could power your home for 860 years.” Message received.
Nuclear fusion has, for decades, been the ultimate “jam tomorrow” story — a fantastical technology that could solve many of the world’s most urgent problems, from energy poverty to climate change. The process is the same that powers the sun — forcing atoms to bind under immense pressures and temperatures. The ideal temperature for a fusion reaction is 200 million degrees centigrade. The resulting fused atom is lighter than the two that made it, and the excess mass is released as energy.
Crucially, it does not generate radioactive waste, like the fission reactors that have left us with stockpiles of toxic waste. Fusion may turn the reactor materials radioactive, but the half-life is 12 years; fissile material will take hundreds of thousands of years to decay.
In short, fusion offers the prospect of endless, clean baseload power. But it has always been deemed just too difficult; the process, after all, requires scientists to recreate the sun. Yet a combination of breakthroughs, advances in materials science and the growing urgency of the fight against climate change has dramatically changed that calculus.
Within the past month, three start-ups have together raised more than $4 billion (£3 billion) from top venture capital investors and billionaires betting on a technology that, if cracked, would indeed change the world. Commonwealth Fusion, a three-year-old spinout from the Massachusetts Institute of Technology, raised $1.8 billion from Bill Gates, George Soros and others this month.
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General Fusion, a Canadian start-up backed by Jeff Bezos that recently announced plans to build its first pilot plant in Culham, Oxfordshire, attracted $130 million in fresh funding in November. And Helion Energy, an eight-year-old firm in Washington, nabbed $500 million, plus another $1.7 billion contingent on hitting development milestones. Investors include LinkedIn founder Reid Hoffman and Sam Altman, the billionaire boss of OpenAI, the artificial intelligence organisation.
Altman put $375 million of his personal cash into the deal. He told CNBC: “I think it is our best shot to get out of the climate crisis.”
In Helion’s case, the funding was based on the results of its sixth prototype, which it said this summer generated temperatures of more than 100 million degrees centigrade — a level that it claimed is sufficient to produce power using its technology. It was the first private company to hit that milestone.
Helion is building its seventh prototype and said that it will produce “net electricity” — which means it will generate more power than is required to run the process — by 2024. Krisiloff said: “We’re getting to a point where the world can plan for fusion to be part of this fight against climate change, and it should be making its way into the way regulators are thinking and planning.”
Commonwealth Fusion is just as ambitious, pledging to demonstrate its first “net energy” machine by 2025, and aiming to operate a commercial power plant by the early 2030s.
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For the unanointed, such timelines may sound reasonable. For industry insiders, they are revolutionary. For example, ITER, a vast multi-government project that includes Britain, aims to produce “first plasma”, the super-hot gas required for the fusion process, by 2025. This would be 40 years after ITER was established in 1985. The bill for the mammoth facility it is building in southern France could top €20 billion (£17 billion).
Its sluggishness is partly due to the difficulty of getting several countries to work in unison, but it is also because the technology is very, very difficult.
In a recent 90-page fusion deep dive, America’s National Academies of Sciences, a government-funded group of independent scholars, estimated that fusion power could start delivering electricity to the grid by 2050, if all goes well.
Brian Wirth, a nuclear engineering professor at the University of Tennessee who helped write the report, said the start-ups were “naive and overly ambitious in terms of what it’s going to take to go from where they are to a demonstration to a reactor on the grid.”
He gave a comparison. The world has produced more than 400 years worth of nuclear power, but getting a new plant built, given the vast upfront cost and regulatory challenges, remains a herculean task. One need only look at EDF’s £20 billion-plus reactor at Hinkley Point, which was licensed in 2012 and is not expected to come online until at least 2025. A new generation of smaller, and cheaper, modular reactors proposed in America must also navigate years of regulatory red tape.
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Fusion reactors have thus far been sub-scale experiments. “We have, at most, minutes of operating experience” with reactors that have generated more energy than they consume, Wirth said.
The first fusion prototype, called a tokamak, was built in Russia in 1958. Shaped like a doughnut, the design uses super- powerful magnets to suspend plasma — the mini-sun that acts as the kitchen for the fusion process — and keep it from touching, and melting, the walls.
For decades, researchers and governments have worked on that core concept repeatedly. Typically, this meant prototypes got bigger and more expensive, yet progress towards demonstrable energy gains slowed. Funding, most of which came from governments, stalled.
The spasm of billion-dollar financings is a dramatic departure. It is driven partly by the climate change imperative, and partly by the spate of breakthroughs achieved by the start-ups.
Yet they must still get past countless obstacles, and two stand out, Wirth said. One is the materials. A fusion reaction generates high-energy neutrons that degrade steel and other materials inside the chamber. Understanding that process, and how to mitigate it, will be crucial.
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Another question has to do with the feedstock. Most fusion developers use deuterium, a hydrogen isotope that is plentiful and found in heavy water, and tritium, a far less common isotope that must be “bred” onsite as part of the fusion process. This has never been done on a large scale. Helion’s process does not use tritium but instead combines deuterium and helium-3.
What is certain is that the level of urgency, and investment, is unprecedented. And it is not solely confined to start-ups. Britain’s Atomic Energy Authority plans to put £222 million into its own pilot facility.
The upstarts, though, flush with cash from some of the world’s richest men, are taking an approach that differs from the plodding pace that typifies most publicly-funded projects. They are rapidly spinning up prototypes and testing new approaches. Wirth said: “There’s a huge benefit to building something, having it break and figuring out how to fix it.”