FUSION FOR THE FUTURE: Princeton Plasma Physics Laboratory (PPPL) Director Steven Cowley oversees the National Spherical Torus Experiment-Upgrade (NSTX-U) test cell, the flagship fusion facility at PPPL, where scientists are working towards a goal of clean, efficient fusion energy helping to combat climate change. (Photo by Elle Starkman/PPPL Office of Communications)

By Donald Gilpin

The Lawrence Livermore National Laboratory in California last week announced that it had achieved fusion ignition, “a major scientific breakthrough decades in the making that will pave the way for advancements in national defense and the future of clean power,” according to the Livermore Lab press release.

That fusion experiment was able, for the first time in history, to produce more energy from fusion than the laser energy required to activate the reaction. 

Theoretically fusion, the nuclear reaction that produces energy from the sun and the stars, could provide Earth with an unlimited source of clean energy without greenhouse gases. New York Sen. Charles Schumer’s statement that  this breakthrough “puts us on the precipice of a future no longer reliant on fossil fuels but instead powered by new clean fusion energy” is accurate, but that future when fusion energy will be efficient enough for commercial use is probably decades away.

“Fusion is the way the stars make energy, and to be able to reproduce that in the lab is phenomenal,” said Steven Cowley, director of the Princeton Plasma Physics Laboratory (PPPL), which provided X-ray measurements in supporting the Livermore experiment. “It’s a major step forward in science. It’s an amazing story. We’ve been involved throughout the process, for about a decade, in helping them understand what’s going on in the experiment by measuring the X-rays.” 

In addition to making the X-ray measurements, the PPPL has been pursuing its own initiatives to reach the goal of efficient fusion energy. “Fusion is so important that having two lines of attack is a very good thing,” said Cowley, who is also a professor of astrophysical sciences at Princeton University. 

He continued, “There’s an awful lot of hard work to do. This result and the results we’ve had in Princeton point to the fact that fusion is possible. We can imagine a future in which the world has these fusion power stations. Now the question is how to bring down the cost so that it becomes economic.”

Describing fusion as “an incredible way to make energy,” Cowley noted that oil or other resources are not necessary to produce energy through fusion. “The resources are not the problem with fusion,” he said. “It’s knowledge — that’s the problem.” Some of Cowley’s colleagues at the PPPL, he said, have been working in the lab for 60 or 70 years, “thinking about science and how to make fusion work.”

Cowley explained that the PPPL specializes in magnetic fusion, different from the inertial fusion approach employed in the Livermore Lab experiment. Inertial fusion is “like a very tiny fusion bomb,” said Cowley. “It’s a little pellet about the size of a peppercorn that explodes with the force in this case of about three hand grenades. They shine lasers onto it and compress the pellet down to about a thousandth of its size, and when it gets really small — it gets hot as well — it starts to do fusion and blows itself apart. And the idea with inertial fusion is you’d have multiple explosions, maybe six per second, that would produce energy.”

In magnetic fusion as practiced at PPPL, however, the fuel is held steady in a magnetic field and is heated up to temperatures of about 200 million degrees. “It starts to fuse, and it continuously fuses, and we add more fuel, and it continues to fuse,” said Cowley, referring to a historic, record-breaking experiment at PPPL in 1994.

Last month the U.S. Department of Energy awarded the PPPL funding of more than $12 million for its ongoing experimental research in fusion energy science. 

One priority for PPPL now is the creation of startup companies, developing the commercial side of fusion.  Stellarators Inc., which has just opened offices on Nassau Street above Hamilton Jewelers, and Satellite Systems in Plainsboro are both working closely with PPPL.

“That seems to be our main thrust in the next few years,” said Cowley, “starting the process of working with industry, making fusion not just a physicist’s thing but something that actually starts to make commercial sense.”

Also in the wake of the Livermore Lab results, the PPPL will be expanding its X-ray measurements group. “There will be more experiments along this line and we will need to get more accurate measurements,” said Cowley. “This all happens in a billionth of a second, so you have to make that measurement in a billionth of a second. There’s some technology needed there.”

Cowley discussed the long view and the role of fusion technology in combating climate change. “The solution to our climate issues has to be a number of technologies,” he said. “Solar is going to play a role, wind will play a role, and I believe that fusion will play a role too.”

He continued, “But I don’t want to say fusion is the only technology, because it’s not ready now, and I want to encourage the deployment of more solar and wind to reduce our carbon output in this country on a rapid basis, and fusion is not ready for that. Climate change is tearing our planet apart now already, and it’s going to get worse.”

Cowley emphasized the importance of Princeton University’s net-zero masterplan led by the Andlinger Center, but he pointed out that fusion energy could be crucial to supplement other energy sources, to “fill the gaps” when the sun isn’t shining and the wind isn’t blowing.

“You need something like fusion that you can turn on when you need it and off when you don’t need it,” he said. “There’s a modern term for that. It’s called firm energy, and it means you can rely on it when you need it.” 

Cowley added that firm energy in the future will probably be provided by fusion and energy storage. “The need for new firm energy sources is a problem that we really don’t have a solution for, so fusion will play that role,” he said.