Energy Secretary Jennifer Granholm on Tuesday announced a “major scientific breakthrough” aimed at harnessing the decades-long quest to harness the energy fusion that powers the sun and stars.
For the first time, researchers at Lawrence Livermore National Laboratory in California have produced more energy in a fusion reaction than was used to ignite it, known as a net energy gain, the U.S. Department of Energy said.
Granholm and other officials said the achievement would pave the way for defense advancements and a clean energy future.
“This is a milestone achievement for NIF researchers and staff, who have dedicated their careers to making fusion ignition a reality, and one that will undoubtedly inspire many more discoveries,” said Granholm said at a news conference in Washington. The fusion breakthrough “will go down in the history books,” she said.
Appearing with Granholm, White House science adviser Arati Prabhakar called fusion ignition a “huge example of what perseverance can really achieve” and an “incredible marvel of engineering.”
Proponents of fusion hope that one day it can generate virtually unlimited, carbon-free energy that replaces fossil fuels and other traditional sources of energy. Producing the energy to power homes and businesses from fusion is still decades away. But the researchers say it’s still an important step.
“It’s almost like the starting gun has been fired,” said Professor Dennis White, director of MIT’s Center for Plasma Science and Fusion and a leader in fusion research. “We should strive to make fusion energy systems usable for climate change and energy security.”
Net energy gain has been an elusive goal because fusion occurs at very high temperatures and pressures, which are very difficult to control.
Fusion works by squeezing hydrogen atoms against each other, causing them to combine into helium, releasing enormous amounts of energy and heat. Unlike other nuclear reactions, it produces no radioactive waste.
Billions of dollars and decades of work have been poured into fusion research, with mind-blowing results — lasting only a fraction of a second. Previously, researchers at the Lawrence Livermore Division’s National Ignition Facility used 192 laser beams and temperatures several times higher than the center of the sun to produce an extremely brief fusion reaction.
A laser focuses a lot of heat on a small metal can. The result is a superheated plasma environment where fusion can occur.
Riccardo Betti, a professor at the University of Rochester and an expert in laser fusion, said the announcement of gaining net energy in a fusion reaction would be significant. But he said there was still a long way to go before generating sustainable electricity.
He likened the breakthrough to the first time humans learned that refining oil into gasoline and igniting it produced an explosion.
“You still don’t have an engine, you still don’t have tires,” Betty said. “You can’t say you have a car.”
The net energy gain achievement is applied to the fusion reaction itself, not the total power required to operate the laser and run the project. For fusion to be viable, it needs to generate more energy and last longer.
Controlling the physical properties of stars is very difficult. Getting to that point has been challenging, White said, because the fuel has to be hotter than the center of the sun. Fuel doesn’t want to stay hot – it wants to leak out and get cold. Containing it is an incredible challenge, he said.
Jeremy Chittenden, professor of plasma physics at Imperial College London, said the net energy gain achieved by the California lab was not surprising, given the progress it had already made.
“That’s not to deny that this is an important milestone,” he said.
Advancing fusion research requires enormous resources and effort. One way is to convert the hydrogen into a plasma, an electrically charged gas, which is then controlled by giant magnets. The approach is being explored in France by a collaboration of researchers from 35 countries, known as ITER, as well as from MIT and a private company.
Last year, the teams working on these projects on two continents announced they had made significant progress on the important magnets needed for the work.