US Department of Energy officials announced a history-making accomplishment in nuclear fusion Tuesday: For the first time, US scientists produced more energy from fusion than the laser energy they used to power the experiment.
A so-called “net energy gain” is a major milestone in a decadeslong attempt to source clean, limitless energy from nuclear fusion – the reaction that happens when two or more atoms are fused together.
The experiment put in 2.05 megajoules of energy to the target and resulted in 3.15 megajoules of fusion energy output – generating more than 50% more energy than was put in. It’s the first time an experiment resulted in a meaningful gain of energy.
“This monumental scientific breakthrough is a milestone for the future of clean energy,” said Democratic US Sen. Alex Padilla of California in a statement.
The breakthrough was made by a team of scientists at the Lawrence Livermore National Laboratory’s National Ignition Facility in California on December 5 – a facility the size of a sports stadium and equipped with 192 lasers.
Energy Secretary Jennifer Granholm on Tuesday called the breakthrough a “milestone.”
“Ignition allows us to replicate, for the first time, certain conditions that are only found in the stars and sun,” Granholm said. “This milestone moves us one significant step closer to the possibility of zero-carbon, abundant fusion energy powering our society.”
Granholm said scientists at Livermore and other national labs do work that will help the US move quickly toward clean energy and maintain a nuclear deterrent without nuclear testing.
“This is what it looks like for America to lead, and we’re just getting started,” Granholm said. “If we can advance fusion energy, we could use it to produce clean electricity, transportation fuels, power, heavy industry and so much more.”
Arati Prabhakar, director of the White House Office of Science and Technology Policy, spoke about how, as a young scientist early in her career, she spent three months at Lawrence Livermore working on its nuclear fusion project.
Prabhakar reflected on the generations of scientists who got to today’s achievement with nuclear fusion. “It took not just one generation but generations of people pursuing this goal,” she said. “It’s a century since we figured out it was fusion that was going on in our sun and all the other stars. In that century it took so many different kinds of advances that ultimately came together to the point that we could replicate that fusion activity in a laboratory.”
Why a net gain in energy matters
We are still a very long way from having nuclear fusion power the electric grid, experts caution. The US project, while groundbreaking, only produced enough energy to boil about 2.5 gallons of water, Tony Roulstone, a fusion expert from the engineering department at the University of Cambridge, told CNN.
That may not seem like much, but the experiment is still hugely significant because scientists demonstrated that they can create more energy than they started with. While there are many more steps until this can be commercially viable, that is a major hurdle to cross with nuclear fusion, experts say.
Lawrence Livermore National Laboratory Director Kim Budil on Tuesday called her lab’s breakthrough a “fundamental building block” to eventually realizing nuclear fusion powering electricity. She estimated it will take “a few decades” more work before it’s ready for commercial use.
“I think it’s moving into the foreground and probably with concerted effort and investment, a few decades of research on the underlying technologies could put us in a position to build a power plant,” Budil told reporters. “With real investment and real focus, that timescale can move closer.”
Past fusion experiments including one in the United Kingdom have generated more energy, but have not had nearly as big of an energy gain. For instance, earlier this year, UK scientists generated a record-setting 59 megajoules of energy – about 20 times as much as the US-based project. Even so, the UK project only showed an energy gain of less than 1 megajoule.
Neither the US nor UK-based projects “have the hardware and steps in place to convert fusion neutrons to electricity,” Anne White, head of MIT’s Department of Nuclear Science and Engineering, told CNN.
Budil said both European fusion projects that run on magnets and the US laser-based system can work alongside each other to push advancements in fusion forward. Granholm added the federal government welcomes private investment in fusion as well.
Budil stressed that there are many more steps to take in the coming decades until nuclear fusion power can turn our lights on and heat our water.
“I don’t want to give you a sense that we’re going to plug the (National Ignition Facility) into the grid; that’s not how this works,” she said.
But Roulstone pointed out that big ambitious nuclear energy projects must start somewhere: In 1942, scientists in Chicago ran the first fission nuclear reactor for just 5 minutes in its first run; 15 years later, the first US-based nuclear power plant went online in Pennsylvania.