Nuclear scientists were able to replicate fusion ignition at least three times this year, marking a significant leap forward in the race to solve the climate crisis, according to a report this month by the Lawrence Livermore National Laboratory. Ignition, a reaction that releases more energy than it consumes, was first achieved by a team at the California laboratory last December. Never before successfully created, it has been chased by researchers for more than a decade and could one day prove to be the key to near-limitless quantities of clean energy. First, though, they had to prove they could do it again. The LLNL report notes that three implosion experiments this year—one in July and two in October—were able to yield a net gain, proving the National Ignition Facility’s ability to create “fusion energy at multi-megajoule levels.” Richard Town, a scientist who leads the LLNL’s inertial-confinement fusion science program, told Nature that he was “feeling pretty good” about the results. “I think we should all be proud of the achievement.”