The US is expected to announce a major breakthrough in fusion energy tomorrow.

The first nuclear fusion experiment to achieve a “net energy gain” has reportedly been carried out by scientists at the Lawrence Livermore National Library in California, according to the Financial Times.

This has been the holy grail of nuclear fusion research since the 1950s. No group so far has been able to produce more energy than is consumed by the reaction.

Sources familiar with the results of the research told the Financial Times that the reaction had produced 1.2 times as much energy as was put in at some point over the last two weeks.

Though the laboratory and US Energy Department declined to comment further on the preliminary data, it said a “successful” test was carried out at the National Ignition Facility.about:blank

US Energy Secretary Jennifer Granholm and under-secretary for nuclear security Jill Hruby are expected to announce “a major scientific breakthrough” at a press conference on Tuesday.

Why would a breakthrough in nuclear fusion be a ‘game changer’?

Around the world, huge amounts of money have been spent on trying to develop nuclear fusion into a viable alternative to other more polluting sources of energy. 

The process involves smashing two atoms together at very high speeds – the same reaction that powers the sun – then harnessing this energy to create electricity. Its proponents say it could power millions of homes without producing carbon emissions or hazardous nuclear waste.

“If this fusion energy breakthrough is true, it could be a game changer for the world,” Ted Lieu, a member of the US Congress from California tweeted after the breakthrough was reported over the weekend.

While the breakthrough could be an incredible scientific achievement, the technology is still at least 10 years away from being a commercially available source of electricity. The lab in the US uses one of the largest lasers in the world and the process requires materials that are difficult to produce.

The equipment needed to turn energy produced from fusion into electricity that can be deployed to the grid also hasn’t been developed yet. So we’re still a long way off nuclear fusion-powered homes.