The US Department of Energy said Tuesday that scientists at a laboratory in California managed for the first time to generate more energy from a fusion reaction than they needed to trigger it. The milestone raises the prospect that some day — perhaps decades from now — the global economy will be run on carbon-free electricity generated by the very process that powers the sun.
“The fusion breakthrough will go down in history,” US Secretary of Energy Jennifer Granholm said during a press conference. “This is what it looks like for America to lead.”
Researchers at the Energy Department’s Lawrence Livermore National Laboratory used lasers to bombard hydrogen isotopes held in a superheated plasma state to fuse them into helium, releasing neutrons and carbon-free energy in the process. It’s a stunning moment for a technology that has failed for nearly half a century, and comes as leaders of the world’s 10 biggest economies — and dozens of smaller nations — have pledged to shift to clean energy sources.
The most immediate impact of the US experiment will be felt by engineers in charge of maintaining the US nuclear weapons stockpile. They’ll be able to use the data to model how warheads are ageing and eliminate the need to conduct new atomic testing. The Energy Department is administering a $1-trillion program to maintain and modernise US nuclear arms and the Lawrence Livermore National Laboratory plays a key role in that effort.
Officials stressed that the main purpose of the facility where the breakthrough took place was to study the behavior of thermonuclear weapons as part of the “stockpile stewardship” programme. To do that, it needed to achieve ignition.
Scientists used 192 high-powered lasers to blast a peppercorn-sized target of deuterium and tritium, two isotopes of hydrogen, in the December 5 experiment. The lasers delivered 2.05 megajoules of energy, and when the target ignited, the fusion reaction produced 3.15 megajoules, lab officials said Tuesday.
“The energy production took less time than it takes light to travel one inch — kind of fast,” said Marvin Adams, deputy administrator for defence programmes at the National Nuclear Security Administration.
The milestone created a net energy gain that scientists have been trying for decades to achieve. It could lead to the development of a commercial fusion power plant in several decades — not the 50 years or longer that researchers once feared, said the lab’s director, Kimberly Budil.
“There are very significant hurdles, not just in the science but the technology — this is igniting one capsule, one time,” she said. “A few decades of research into the underlying technologies can put us in the position of building a power plant.”
Power Source of Stars
Fusion energy is produced by melding together atoms and is the power source of stars, whose immense gravity crushes together atoms of hydrogen to form helium. With fusion, there’s no long-lived radioactive waste — that’s a stark contrast to the fission technology currently used at nuclear reactors to generate electricity.
Fusion is unlikely to help boost faltering progress towards net-zero emissions, at least not without work that most experts think will take decades of additional development. That means this breakthrough probably won’t help displace traditional fossil fuels when the world is facing an entrenched energy supply crunch and greenhouse gas levels are still rising.
“We have to take a positive but skeptical approach,” said Andrew Sowder, a senior technical executive at the independent, non-profit EPRI, formerly known as Electric Power Research Institute. “You are going to have to demonstrate you can take the energy and turn it into something useful.”
To move this technology out of the lab, a fusion system would need to be affordable and easy to build. However, the Lawrence Livermore test uses some of the most powerful lasers ever built: They’re big, costly and not readily available for mass deployment. That would make it difficult to convert this technical accomplishment into a successful business.
“The fact that you have net energy gain does not mean you’ll have a commercial device on the market,” said Chris Gadomski, head nuclear analyst for BloombergNEF. “Yes, we have fusion, but at what cost?”
Still, the announcement should unleash funding and support for a civilian technology development programme, said Stephen Dean, president of Fusion Power Associates, a non-profit public benefit corporation.
Startups including Commonwealth Fusion Systems and Helion Energy attracted $2.3-billion in support in 2021, and backers will likely direct more than $1-billion to the field this year, according to BloombergNEF. Other notable companies include Marvel Fusion, TAE Technologies, General Fusion, Tokamak Energy and Zap Energy.