Encouraged by major technological advances and colossal private investments, the nuclear fusion sector has shifted gears in the United States, and is expected to produce electricity on a large scale within ten years.
“It’s no longer just about science, but about delivering a product,” summarizes Dennis Whyte, professor at the Massachusetts Institute of Technology (MIT), to characterize what he considers a “turning point” in nuclear fusion.
If the old dream of generating energy like the sun, which fusion is capable of, has fueled fundamental research for decades, the project is now attracting the private sector.
In two years, the latter has more than doubled its investments, which reached 5.9 billion dollars in total at the end of 2023, compared to only 271 million from the public sector.
Around two thirds of start-ups, of several nationalities, surveyed by the Nuclear Fusion Association (FIA) see the first fusion power plant connected to the electricity grid by 2035 at the latest.
The young company Helion Energy even signed an agreement with Microsoft last year for a capacity of 50 megawatts (MW) operational in 2029.
In addition to the influx of private money, the sector is in turmoil because “over the last two years, we have scientifically demonstrated that it is possible”, argued, during the CERAWeek energy conference, Pravesh Patel, of the Focused Energy start-up.
“It’s like when the Wright brothers took off,” he said, referring to what is considered the first flight of a powered airplane in 1903.
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Among the major milestones, the experiment at the Lawrence Livermore National Laboratory (LLNL), in December 2022 in California, during which the energy produced was greater than that used, a first, is considered the most notable.
Fusion consists of assembling two atom nuclei derived from hydrogen, most often deuterium and tritium, in a confined space, at a heat of more than 100 million degrees Celsius.
Together, they form a helium nucleus and release neutrons, which will bombard the walls of the reactor and raise their temperature.
This heat will then be converted into electricity, thanks to the water vapor produced when the water comes into contact with the outside of the reactor.
The advantage of fusion is that it does not generate emissions and does not risk accidents like its cousin fission, on which it also has the advantage of producing much less waste.
The majority of start-ups have chosen the so-called magnetic confinement technology, that used by the tokamak, the best-known reactor model. It differs from the so-called inertial confinement method, used by the LLNL, which uses lasers.
Helion directly recovers the energy inside the reactor without going through the steam box, and its process does not produce neutrons, which avoids projections on the walls and their erosion.
This approach “gives us an advantage in reaching commercialization,” says a spokesperson.
Until recently, the economic viability of nuclear fusion appeared uncertain, because magnetic confinement required the manufacture of gigantic magnets.
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But recently published studies by researchers at MIT and the start-up Commonwealth Fusion Systems have shown that fusion is possible with much smaller magnets than initially imagined.
“Overnight, this reduced the cost per watt by 40,” responded Dennis Whyte for MIT News. “Now, fusion has a chance” of becoming a reality in the energy supply, according to him.
With its two billion dollars in private capital, Commonwealth is, by far, the company to have raised the most funds in the sector. It plans to activate its demonstration reactor, SPARC, next year, then open its first plant in the early 2030s.
There are still many uncertainties, but if successful, Commonwealth and Helion would allow the Americans to be the first to arrive at commercial electricity production, a step that no other country is aiming for before 2035, at best.
“Commonwealth is a great example of what the private sector can do with a commercial objective compared to the public sector,” emphasizes Pravesh Patel.
“The United States has an advantage, in a certain way,” recognizes Dennis Whyte, who mentions the ability of university laboratories to “convert their research (into products) better than in other countries” as well as the strong culture of venture capital, which allows young companies to get started.
From the semiconductor revolution to that of the Internet, “the United States has already won this kind of race.”
