Fusion at the Threshold: Lawrence Livermore’s Record-Breaking Shot and the Future of Energy
As LLNL’s National Ignition Facility achieves a new high in fusion energy yield, its leaders reflect on the path ahead—filled with scientific promise and political challenges.
In a quiet corner of California’s East Bay, nestled on a one-square-mile campus, the Lawrence Livermore National Laboratory (LLNL) is rewriting the playbook for humanity’s clean energy future. This spring, LLNL scientists at the National Ignition Facility (NIF)—home to the world’s most powerful laser—achieved a significant milestone in pursuing fusion energy.
“We just had our eighth shot that exceeded the ignition threshold,” said Kimberly Budil, director of LLNL, in a public appearance earlier this month. “And this one will be a new record for us.”
Though the official numbers have yet to be released, Budil hinted that the fusion yield would surpass all previous results, likely reaching a gain of seven to eight megajoules, well above the last records of 2.5 and 5.2 megajoules.
“Don’t tell anybody,” she added playfully. “It’s not official yet.”
While the results may still be under wraps, what’s clear is that LLNL’s scientists are mastering a process once considered impossible: controlled fusion ignition. This breakthrough—where more energy is produced than consumed in the reaction—edges the world closer to realizing fusion as a safe, abundant, and carbon-free power source.
Precision Science on a Microscopic Stage
Fusion ignition at LLNL isn’t a brute-force event—it’s a ballet of subatomic precision. At the heart of each experiment is a diamond capsule just two millimeters in diameter, encased inside a gold cylinder about the size of a pencil eraser. The capsule contains deuterium-tritium (DT) fuel, which is compressed and heated to extreme conditions using 192 carefully calibrated laser beams.
Budil explained the delicacy: “The lasers must be pointed with tens-of-microns accuracy. Everything has to be about an order of magnitude better than we initially thought.”
The road to ignition is built on learning and iteration. Each shot is tailored to the unique physical quirks of that day’s capsule. “We do very detailed metrology on each capsule,” she said. “We’ll predict the result, take a shot—spoiler: it won’t work—but we’ll learn a lot. Then we tuned the laser and tried again. We’re getting faster at that cycle.”
And it’s not just laser timing or alignment. LLNL scientists constantly experiment with capsule materials and doping methods to improve implosion symmetry and energy yield. “These new diamond capsules have materials doped into them to shape the implosion,” Budil said. “We’re improving manufacturing processes to control better how those implosions work.”
Fusion Fest: Celebrating Progress, Framing the Future
Budil shared news of LLNL’s latest achievement not at a press conference or DOE briefing but at Fusion Fest, an international gathering of scientists, journalists, policymakers, and investors hosted by The Economist in London on April 8, 2025. The event highlighted the growing excitement around fusion’s potential role in the global energy mix.
“I can announce for the first time anywhere—we just had our eighth ignition shot,” Budil told a captivated audience. The moment sparked applause and marked a symbolic passing of the torch from decades of promise to present-day progress.
The event also offered a candid window into the extraordinary effort behind NIF’s breakthroughs. “When we started this process, the laser was built to deliver about 1.8 megajoules,” Budil explained. “Over time, we’ve raised that to over 2.2 megajoules, and we’re now trying to get the highest yield with the lowest possible laser energy.”
That trade-off is essential for practical fusion energy, and the lab is now pushing toward “enhanced yield capability”—a project that will install new laser amplifier glass to raise energy delivery to 2.6 megajoules or more. “For the next decade,” she said, “we’ll have a competent machine again, to push toward higher yields and see where we can take this technology.”
The Journey to Ignition: December 2022 and Beyond
While the latest result marks a new peak, the turning point came in the early hours of December 5, 2022. After twelve years of painstaking experimentation, the NIF team achieved the holy grail: fusion ignition.
That morning, 192 laser beams focused 2.05 megajoules of ultraviolet light onto a tiny DT capsule. The reaction produced 3.15 megajoules of fusion energy—more than the input- enough to launch LLNL into scientific record books.
“You see one diagnostic and think, ‘Maybe that’s not real,’” recalled Annie Kritcher, the experiment’s lead designer. “Then you see more diagnostics pointing to the same thing—it’s just a great feeling.”
The results stunned even the most seasoned team members. “The pursuit of fusion ignition in the lab is one of the most significant scientific challenges ever tackled by humanity,” Budil said in the aftermath. “Achieving it is a triumph of science, engineering, and most of all, people.”
The breakthrough marked a significant contribution to the National Nuclear Security Administration’s (NNSA) Stockpile Stewardship Program, which relies on fusion science to maintain the U.S. nuclear deterrent in the absence of underground testing. But it also energised hopes that inertial confinement fusion could become the cornerstone of a clean energy future.
Public Funding, Private Ambitions
While LLNL’s primary mission remains national security, Budil is determined to bridge the gap between public science and commercial fusion development. The lab is now establishing a new institute, led by Dr. Tammy Ma, to explore fusion energy technology and policy in collaboration with private companies.
“A real priority for me is identifying what I would call a pre-competitive space,” Budil said. “Everyone needs the same things—like higher-gain targets. So let’s pool resources and work on those problems together.”
One such goal is to reach gains of 10 to 15, an essential step toward commercial viability. “Once we get to high enough gain, we can simplify target geometries,” she said. “Then individual companies can innovate on their own designs.”
Budil emphasised that the lab’s role isn’t to build power plants. But it can help others de-risk core technologies. “We’re sharing power plant designs and engineering work from earlier efforts,” she added. “That includes everything from the igniting target to systems that deliver power to the grid.”
Science vs. Politics: A Budgetary Balancing Act
For all its recent success, LLNL now faces headwinds from Washington. The Trump administration’s proposed budget for fiscal year 2026 includes deep cuts to non-defence scientific research, with DOE’s Office of Science and the NNSA’s fusion programs squarely in the crosshairs.
“It’s a very complicated time in the government in the United States right now,” Budil said diplomatically. “The National Nuclear Security Administration has, over time, been more or less insulated from this process, but it is very stressful for our colleagues on the federal side.”
The uncertainty is more than bureaucratic—it threatens the momentum built from years of painstaking progress. The number of annual experiments at NIF is already dropping due to ageing infrastructure and delayed maintenance. “We used to do 400 total experiments yearly,” said Budil. “That’s been steadily coming down to 350.”
While LLNL has received some support for refurbishment, the long-term health of American fusion research now depends on consistent federal investment. “There’s an opportunity here,” Budil noted. “We’re working with the Secretary of Energy to implement changes that will really benefit the labs. But we need to push forward.”
Looking Ahead: The Horizon of Fusion Energy
As LLNL celebrates new records and continues to optimise NIF’s performance, the big question remains: How close is fusion energy to reality?
“There’s a long journey ahead,” Budil acknowledged. “But the horizon is coming into view for the first time.”
That horizon includes strengthening collaborations with industry, refining high-gain targets, and eventually developing simplified, cost-effective reactor designs. It also means continuing advocacy for scientific funding amid political uncertainty.
Despite the obstacles, Budil remains hopeful. “I’m a glass-is-half-full kind of person,” she said. “And if we stay focused, fusion can be a cornerstone of our clean energy future.”
For now, the laser beams keep firing, and the scientists at LLNL continue to learn from every pulse of light. Each shot may last just a fraction of a second, but with each one, the future of fusion gets slightly brighter.