Scientists have achieved a net energy gain in nuclear fusion for the second time, marking major progress towards realising the potential of the near-limitless energy source. A team at the Lawrence Livermore National Laboratory in California, who first achieved the feat last December, claimed to have passed a new milestone with fusion ignition by producing even greater energy output than the original experiment. The nuclear fusion process has been described as the “holy grail” of clean energy, as it requires no fossil fuels and leaves behind no hazardous waste. Instead it mimics the natural reactions that occur within the Sun, though harnessing its potential has puzzled scientists since the 1950s. Achieving nuclear fusion ignition is a crucial step towards building commercial power stations, though the technology needs to be significantly scaled up from the current experiments for it to be a viable energy source. The first ever successful fusion energy gain experiment on 5 December, 2022, used lasers to fuse two light atoms into a single one, releasing 3.15 megajoules of energy from 2.05 megajoules of input. Researchers described the milestone as “one of the most significant scientific challenges ever undertaken by humanity” that would “enable the next steps toward clean fusion energy for the future”. Scientists that were not involved in the fusion experiments said the advance had profound implications for the future of the planet. “We are witnessing a moment in history: controlling the power source of the stars is the greatest technological challenge humanity has ever undertaken,” said physicist Arthur Turrell. “This experimental result will electrify efforts to eventually power the planet with nuclear fusion – at a time when we’ve never needed a plentiful source of carbon-free energy more.” A spokesperson for the Lawrence Livermore National Laboratory said the final results of the latest experiment are still being analysed. The lab plans to present the results at upcoming scientific conferences and in peer-reviewed journals. Several companies are already investing heavily in nuclear fusion, with Microsoft making the world’s first purchase agreement earlier this year. The US tech giant made the deal with Helion Energy, which aims to set up a nuclear fusion power plant within the next five years despite the challenges remaining to make it commercially viable. Helion chief executive David Kirtley said at the time: “We still have a lot of work to do, but we are confident in our ability to deliver the world’s first fusion power facility.” Read More Superconductor breakthrough could represent ‘biggest physics discovery of a lifetime’ – but scientists urge caution Microsoft makes world first nuclear fusion energy deal Zuckerberg says he is ‘ready today’ but ‘not holding breath’ for cage fight with Musk Musk pledges to fund legal bills of X users ‘unfairly treated’ by employers for posts Scientists want to hack the planet to cool it down. The consequences could be extreme