For many years, physicists have joked that nuclear fusion is always thirty years away. No matter what year you ask, it makes no difference. The response is the same every time. And that joke hurt for the majority of the twentieth century because it was mostly accurate.
However, something has changed. Not overnight, not dramatically; rather, it’s more akin to how a long-stalled train eventually begins to move. At first, slowly, almost imperceptibly. Then you realize the platform is behind you when you look up.
Fusion remained a theoretical marvel that constantly ran afoul of practical constraints for more than 70 years. Because of their intense heat and gravitational pull, stars are able to do this with ease. It has proven extremely challenging to replicate those conditions on Earth, which involve heating gases above 100 million degrees Celsius and maintaining their stability with strong magnetic fields or lasers. The energy generated frequently fell short of what was required to run the reaction itself in the few times that scientists were able to achieve fusion in a laboratory setting. The history of fusion is replete with significant events that seemed more significant in press releases than they actually were, and that is a challenging math problem to solve.
It was not helped by the 1989 cold fusion incident. Claims of room-temperature fusion that the larger scientific community was unable to verify were made public by two scientists. The incident caused long-lasting harm to public confidence. Since then, there have also been more subdued setbacks: instances of genuine scientific advancement that were exaggerated beyond what the data could substantiate, leaving investors and the general public doubtful.
It’s more difficult to identify a single breakthrough that has changed. It’s more of a convergence. Researchers can now model plasma behavior with a level of precision that was previously unattainable thanks to advancements in supercomputing. Magnetic tape has been made thin and robust enough by materials science to enable the development of new reactor designs. Manufacturing issues that previously appeared unsolvable have been resolved by three-dimensional printing. In a recent assessment, Michael Delage, the chief technology officer of General Fusion, a Vancouver-based company, stated unequivocally that the underlying science and the capacity to model the behavior of plasmas have truly advanced, much of it occurring in secret and out of the public eye.
The next step has been private investment. About 35 fusion-focused startups had raised nearly $2 billion in funding as of a few years ago. This money came from venture capital firms, philanthropists, and, somewhat surprisingly, oil and gas companies hedging their long-term bets. At the time, Helion Energy announced a $500 million fundraising round, the biggest for a private fusion company. Another competitor, TAE Technologies, has gained support from investors who think the business is getting close to what they refer to as its penultimate step toward commercial viability. The degree of significant financial commitment is unprecedented in this field, though it remains to be seen if that confidence is justified.
The biggest project in progress is ITER, a reactor being built in southern France for more than $25 billion. It is a massive device that is shaped like a doughnut and is intended to contain plasma in a strong magnetic field.
Its goal is to achieve the first sustained plasma burn by 2035 at the latest. According to that schedule, a finished electricity-producing pilot plant wouldn’t be available until at least the mid-2040s. That schedule is annoying to those who are keeping a close eye on the climate situation. ITER might fulfill all of its commitments. It’s also possible that smaller, quicker-moving private startups were ten years ahead of it in producing significant results.
Even if fusion succeeds in the end, it’s important to be clear about what it isn’t. Daniel Jassby, a former employee of Princeton Plasma Physics Lab, has persistently brought up the fact that some of the neutron byproducts from deuterium-tritium reactions pose unique radiation management challenges. Fusion does not produce long-lived nuclear waste in the conventional sense, and it would not pose the same catastrophic meltdown risks as fission. However, it’s not a zero-complication technology, and portraying it as such would be unjust to the real engineering difficulties that lie ahead.
However, the fundamental argument for fusion is still very strong. The fuel is plentiful and consists of tritium derived from lithium and deuterium extracted from seawater. If sustained, the energy output would be far greater than anything else. Without the intermittent nature of solar or wind power, a functional fusion plant could be integrated into current electrical grids. It could generate green hydrogen on a large scale. Over time, it might change the fundamentals of energy economics in ways that are hard to fully envision from where we are now.
Spending time with the individuals working on this gives me the impression that something has actually changed over the past ten years, not just the technology or the funding, but also the attitude. A new generation of engineers and physicists with a focus on business has entered the field; these individuals were not affected by the embarrassment of cold fusion. They are more concerned with getting power onto a grid than they are with theoretical elegance.
It remains genuinely uncertain whether fusion will reach that grid by 2030, 2040, or later. However, the old joke about being thirty years away is beginning to feel more like history than prophecy.
