On Dec. 5, 192 lasers at the National Ignition Facility at the Lawrence Livermore National Laboratory in California fired a synchronized shot at a golden cylinder about the size of a jelly bean. With exquisite precision, the capsule focused the laser light on a grain of frozen hydrogen. For a fraction of a second, the temperature in the hydrogen exceeded that in the core of our Sun, forcing the nuclei of the hydrogen atoms to merge with each other.
Scientists measure progress in these experiments by comparing the energy put into the reaction to the energy that comes out. At NIF there was a net gain when 2.05 megajoules of energy became 3.15 megajoules on the other end. For the first time, we have indisputable evidence that the lasers released nuclear energy from the fuel under controlled laboratory conditions.
Senator Charles Schumer of New York declared the breakthrough propitious, saying in a statement, “This astonishing scientific advance puts us on the precipice of a future no longer reliant on fossil fuels but instead powered by new clean fusion energy.”
But we won’t have fusion from lasers anytime soon because the lasers are terribly inefficient: They require about 300 megajoules to fire a shot — enough to power the average American home for three days. To be commercially relevant, the efficiency would have to improve dramatically, the reaction would have to be repeated at rapid sequence and the targets would have to be manufactured at low cost in large numbers.
Given that it will likely be decades until we can power the electricity grid with fusion energy, it is fair to ask whether we should even consider this to be good news for the climate. Katharine Hayhoe, the Texas Tech climate scientist, said that it isn’t. “We already have the technologies we need to decarbonize 80 percent of the electricity sector by 2030,” she tweeted.
Proving that it’s possible to release energy from fusion in a laboratory will neither meet our immediate need to reduce carbon emissions nor help us control the damage we have already done to the climate. But we have to think beyond our present task of net zero — cutting emissions to as close to zero as possible.
The decision to ramp up investment into fusion in the wake of this breakthrough is ultimately a question of how much we value the lives of future generations. Wind and solar energy often require large installations that take up huge swaths of land (with the exception of offshore wind). Moreover, solar and wind work better in some parts of the world than in others. Much of Europe is considerably farther north than the United States and gets less sunlight during the winter. Most of us in Europe also don’t live on an island that we can surround with wind farms.
Nuclear power — including fusion — is a way to generate a huge amount of power in a small space. That’s a major advantage in a world with already intense pressures on a finite amount land; future generations deserve a shot at this form of relief.
Nuclear fusion is a costly enterprise, no doubt. Expenses for the National Ignition Facility, or NIF, total $3.5 billion so far. Other similar projects in the works are expected to eat up more than $20 billion. But in the past decade, it has also attracted the interest of private investors. After the NIF breakthrough, it will likely draw billions of dollars more in funding from both private and public sectors.
Richard Black, a former BBC correspondent, cautioned on Twitter that generating power from nuclear fusion, even if technically feasible, “might prove prohibitively expensive.” By the time the technology is ripe for commercial application, he said, “many countries will already have virtually removed fossil fuels from their power system. And there will be no point, 15 years after that, in replacing clean and extremely cheap renewables with clean and probably expensive fusion.”
The possibility that we will have mostly decarbonized our economies by the time nuclear fusion becomes commercially viable is not a given. The solar and wind projects we’re building now must be accompanied by sufficient energy storage, and we are nowhere near the capacity we need to scale up these energy sources. It’s also possible that nations will choose to invest more in nuclear fission, which is used in today’s nuclear power plants, to phase out fossil fuels.
Neither nuclear fusion nor fission release carbon dioxide. Both can produce vast amounts of energy from small volumes of fuel. But unlike fission, fusion does not create long-lived radioactive waste. Since fusion does not lend itself to runaway reactions or nuclear proliferation, it is reasonable to expect that it will be less expensive than nuclear fission power, once the technology is mature.
Material science, computing and artificial intelligence are all contributing to making nuclear fusion more energy efficient. Much like how robots can suddenly walk after toppling over for decades, it will become practical not because of one big breakthrough, but by countless incremental improvements.
In the weeks to come, scientists will want to know whether NIF’s success was a one-shot miracle or can be reliably reproduced. But we now have a vibrant, international community of researchers, engineers and investors who are pushing nuclear fusion technology forward.
Investing in nuclear fusion now will not make the next decades of accelerating climate crisis any easier. But after all the damage that our short-term thinking has done to this planet, let us think past 2050, and show our children that we care.
Sabine Hossenfelder is a physicist, an author and a producer of the YouTube channel Science Without the Gobbledygook. She works at the Munich Center for Mathematical Philosophy.
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