Overnight, news broke that the National Ignition Facility, a U.S. government research lab, was the first to achieve net-positive nuclear fusion. When lasers hit the tiny fuel pellet, it created an explosion that released more energy than the lasers delivered.
For decades, fusion power has been just around the corner. Is this the moment we’ve all been waiting for?
Maybe.
First, the details: The Financial Times reported yesterday that the NIF had sparked a fusion reaction that generated 2.5 megajoules of energy, about 20% more than the 2.1 megajoules of laser energy that zapped the fuel pellet. If that holds up under scrutiny, it represents the first time that a controlled nuclear fusion experiment of any kind produced more power than it consumed.
The Lawrence Livermore National Laboratory, which houses the facility, has so far refused to confirm the report. But three outlets — the Financial Times, The Washington Post and Bloomberg — all cited sources familiar with the experiments. Energy Secretary Jennifer Granholm and Jill Hruby, the undersecretary for nuclear security, are expected to make an official announcement tomorrow.
“If this report is true, then this is just a huge scientific achievement in the pursuit of fusion,” said Carolyn Kuranz, an associate professor at the University of Michigan who has performed experiments at the NIF.
Investors have grown bullish on fusion in recent years, plowing $2.7 billion into startups in the last year alone. Advances in high-temperature superconductors, computing power and artificial intelligence have coincided to propel the field forward at a remarkably fast pace.
High-profile names like Breakthrough Energy Ventures, Khosla Ventures and Chris Sacca’s Lowercarbon Capital have made some significant investments in fusion power startups in recent years.
“There couldn’t be a more significant step toward fusion than what NIF has accomplished,” Sacca told TechCrunch. “So today we offer the naysayers our thoughts and prayers.”
This week’s news isn’t the first time in recent memory that the NIF has made a splash. In August, it published a paper detailing a 2021 experiment that released 71.5% of the energy that the lasers put in. In a pleasant surprise, that yield was twice what researchers had expected and eight times higher than any previous NIF attempt.
Despite the drumbeat of announcements and investments, commercial-scale fusion still remains out of reach. The definition of “net-positive” is based on a 1997 report put forth by the National Academies of Science, which said that an experiment would be considered net-positive if the amount of energy released by the fusion reaction exceeded the amount put into the reaction. It does not take into account inefficiencies in converting electricity to laser or magnetic energy, the overhead of the facility or any ancillary functions. So while the NIF may have achieved net-positive fusion power, it probably wasn’t enough to keep the lights on at the lab during the shot.
“If we’re talking about getting fusion to the grid, yes, there are a lot of technological but also scientific hurdles that need to be overcome,” Kuranz told TechCrunch. But even though the reported result appears to fall short of what’s required for commercial fusion, it’s still a welcome and necessary step, she added.
The promise of fusion power has been just over the horizon since 1952, when the first hydrogen bomb was detonated on an atoll in the Pacific Ocean. The key to fusion power is controlling the superheated plasma that’s required to force two small atoms (usually isotopes of hydrogen) to fuse into one, a process that unleashes enormous amounts of energy. But getting the plasma hot and dense enough to generate favorable conditions requires tremendous amounts of energy itself — so much energy that all prior controlled fusion experiments have consumed more than they’ve produced.
Most fusion experiments and startups use magnets to confine and control the plasma. In magnetic confinement, powerful superconducting magnets compress the plasma into one of a range of shapes depending on the design of the reactor.
The NIF takes a different approach. Known as inertial confinement, it uses energy from lasers to create the right conditions. At the research lab, up to 192 lasers are shot into a one-centimeter-long gold cylinder known as a hohlraum, where they zap its insides to generate X-rays. Those X-rays then bombard the surface of a tiny, cryogenic fuel pellet contained within. The pellet is composed of two isotopes of hydrogen, deuterium and tritium. As the outside of the pellet turns into a hot plasma, it expands and compresses the rest of the pellet, igniting it. Voila, fusion.
Every approach to fusion power is challenging, but inertial confinement might be particularly so. With magnetic confinement, computers can swiftly adjust the parameters of the magnetic field to nurse the plasma along. With inertial confinement, neither computers nor operators have the opportunity to adjust things on the fly. Everything has to be perfectly configured before the lasers fire — the hohlraum has to be in just the right place, the lasers have to be aimed just so, and the fuel pellet has to be at just the right temperature.
To get inertial confinement ready for commercial use, a lot of pieces still have to fall into place. Currently, NIF can perform a few shots per day, far short of the tens or hundreds of thousands per day that’ll be required for grid-scale fusion power plants. Manufacturing the hohlraums at scale will be challenging, as will powering and targeting the high-energy lasers so they can perform rapid-fire shots day after day. Tritium, one of the fuels, is incredibly rare on Earth, and finding a long-term supply will be hard. So, too, will be transforming the energy from those explosions into electricity for the grid.
Some of those challenges are shared by magnetic confinement fusion, too, so progress on one front could lead to advances on another. “There are a lot of places where magnetic confinement and inertial confinement can work together,” Kuranz said.
The NIF news comes at a time of rapid advancement across fusion research, and at a time when concerns about climate change and energy equity are growing. “This is such a transformative time,” she said. With the world’s population still growing and many people still living without reliable access to electricity, “there’s this urgent need not just for clean energy, but an urgent need for energy.”
Fusion may not be ready to plug into the grid tomorrow, and it may not be for a decade or more. But it’s also never been closer.