This story was updated at 12 p.m. EST.
The Department of Energy announced Tuesday that its scientists have produced the first ever fusion reaction that yielded more energy than the reaction required, an essential step in the long path toward commercial fusion power, officials said.
The experiment Dec. 5, at the Lawrence Livermore National Laboratory in California, took a few billionths of second. But laboratory leaders said today that it demonstrated for the first time that sustained fusion power is possible.
What comes next is even harder: proving that the technology can work not only in highly structured laboratory experiments but eventually in commercial reactors. That may take decades. But DOE’s achievement of a “net gain” of energy in the lab gives another boost of confidence to a growing corps of fusion entrepreneurs and researchers.
“From my perspective, this is the proof that the physics work for net gain,” said Andrew Holland, CEO of the Fusion Industry Association, an industry advocacy group, in an interview before the announcement.
Here’s four issues to know about the milestone’s significance and next steps:
Why is this so important, and what did DOE scientists do?
Scientists at DOE’s National Ignition Facility at LLNL have been working for decades to show that a fusion reaction — the same process that fuels the sun and stars — can produce more power than is needed to create the reaction.
To achieve net energy for the first time, the scientists fired a “shot” from their cluster of lasers at a container enclosing a small capsule holding hydrogen isotope fuels. The laser beams hitting the container generate X-rays that bombard the fuel, triggering an inward-directed explosion that fuses the hydrogen atoms together.
Scientists outside DOE believe the lab was able to increase the power of the laser shot, creating a fusion reaction that yielded more energy than the lasers produced, according to Stephen Dean, president of Fusion Power Associates, a nonprofit organization that advocates for fusion power.
The ignition laboratory’s implosions were over in billionths of a second. That’s long enough, however, to provide important data to the facility’s scientist researching nuclear weapons, Dean said.
Tuesday’s announcement has been at least a decade in the making, and hit a new milestone a little more than a year ago.
In an August 2021 test, Lawrence Livermore scientists reported hitting a record new output from its cluster of lasers, hitting a target the size of a BB to generate 10 quadrillion watts of fusion power for 100 trillionths of a second. The fusion reaction produced 70 percent of the energy that had gone into the laser shot, the journal Nature reported at the time — approaching, but not yet reaching, the achievement being announced Tuesday.
Is the DOE process the leading option for commercial fusion?
Private fusion companies have raised nearly $5 billion from wealthy investors and corporations hoping to get in on the ground floor of a possible mega-industry of the future.
The biggest investments have gone to companies developing doughnut-shaped reactor designs called by a Russian name — tokamak, a fusion power approach that competes with LLNL’s fusion ignition, which uses a different process to achieve the reaction.
A tokamak works by heating to over 100 million degrees Celsius, creating a swirling plasma of hydrogen isotopes that — if all works as planned — would collide to create the fusion reaction. Magnetic fields generated by super-magnets then would contain the plasma to keep it from destroying the reactor.
The International Thermonuclear Experimental Reactor (ITER), a massive international project under construction in France in which the United States is participating, envisions a tokamak reaction. That project has made steady progress, but has also faced cost overruns and delays. In November, the organization reported challenges with first-of-a-kind components that needed “extensive repairs.”
What is the next step in fusion development?
Fearful that China might wind up with dominating fusion energy in the second half of this century, Congress in 2020 told DOE to begin funding development of a utility-scale fusion pilot plant that could deliver at least 50 megawatts of power to the U.S. grid.
The pilot plant is to be a key test of whether fusion reactors can be workable and affordable as the nation’s everyday main source of electricity, observers say. DOE hopes that private companies will form teams of experts from national laboratories and universities to speed their research.
In September, DOE invited private companies to apply for an initial $50 million in research grants to help fund development of detailed pilot plant plans.
“We’re seeking strong partnerships between DOE and the private sector,” a senior DOE official told E&E News recently. The official was not willing to speak on the record, saying the grant process is ongoing and confidential.
As the competition proceeds, DOE will set technical milestones or requirements, challenging the teams to show how critical engineering challenges will be overcome.
DOE’s goal is “hopefully to enable a fusion pilot to operate in the early 2030s,” the official added.
At least 15 U.S. and foreign fusion companies have submitted requests for an initial total of $50 million in pilot plant grants, and some of them are pursuing the laser-ignition fusion process that LLNL has pioneered, said Holland. He did not name the companies because the competition is confidential.
What are the key hurdles confronting fusion?
The ignition process that Lawrence Livemore scientists pioneered requires exacting maintenance of the laser cluster in between shots. A typical target costs $100,000 or more and requires hundreds of hours to construct, said British mathematician and author Arthur Turrell, who was present for one Lawrence Livermore shot.
Making this technology work on a commercial scale would escalate those requirements.
“Once you get a single shot working well, you have to repeat it, 10 times a second” to have a sustained commercial reaction, a senior DOE official said recently, speaking on condition of anonymity. “That requires a laser that can fire 10 times a second. It is not fundamentally impossible, but it is very difficult from an engineering perspective.”
With tokamaks, reactors face the challenge of having to make their own fuel, breeding one of the hydrogen isotope fuels — tritium — inside the reactors. There also is a need to improve protection of the reactor from intense heat and neutron bombardment.
“It’s not straightforward once you’ve made fusion happen as we have, to go to commercial fusion,” said Steven Cowley, director of DOE’s Princeton Plasma Physics Laboratory, at a White House conference on fusion in April. “But we have the tools to do it.”
The steepest hurdle may be money. Companies have to prove there is a path to a cost for fusion that could be competitive, said Geoff Olynyk, a senior expert in sustainability at McKinsey & Co., in an interview.
“All of the fusion companies are targeting that, but there’s no proof that any of them can do it. The first demonstrations will be extremely expensive,” he said.
“It’s a race right now to get some of these pilot plants online,” Olynyk said.
Correction: An earlier version of this article incorrectly described the energy going in and out of the fusion experiment.