This new breakthrough opens the door to limitless clean energy.

The time has finally come. Scientists at the Lawrence Livermore National Laboratory (LLNL) are the first in the world to demonstrate net energy production from nuclear fusion.

In other words, theirs was the first ever nuclear fusion experiment to produce more energy than was required to run the experiment in the first place.

Researchers achieved the milestone, also known as fusion ignition, at LLNL’s National Ignition Facility (NIF) during a controlled fusion experiment last Monday, Dec. 5, according to a statement from the US Department of Energy (DOE). They waited for peer-review results before revealing the results to the world.

US officials announced Tuesday that researchers have produced a nuclear fusion reaction resulting in a net energy gain. Follow here for live news updates.

WASHINGTON, Dec 12 (Reuters) — The U.S. Department of Energy on Tuesday will announce that scientists at a national lab have made a breakthrough on fusion, the process that powers the sun and stars that one day could provide a cheap source of electricity, three sources with knowledge of the matter said.

The scientists at Lawrence Livermore National Laboratory in California have achieved a net energy gain for the first time, in a fusion experiment using lasers, one of the people said.

While the results are a milestone in a scientific quest that has been developing since at least the 1930s, the ratio of energy going into the reaction at Livermore to getting energy out of it needs to be about 100 times bigger to create a process producing commercial amounts of electricity, one of the sources said.

For the first time ever, US scientists at the National Ignition Facility at the Lawrence Livermore National Laboratory in California successfully produced a nuclear fusion reaction resulting in a net energy gain, a source familiar with the project confirmed to CNN.

The US Department of Energy is expected to officially announce the breakthrough Tuesday.

The result of the experiment would be a massive step in a decadeslong quest to unleash an infinite source of clean energy that could help end dependence on fossil fuels. Researchers for decades have attempted to recreate nuclear fusion – replicating the fusion that powers the sun.