According to three sources with knowledge of early findings from a recent experiment, U.S. government scientists have achieved a net energy gain in a cold fusion reaction.

If verified, it would be the first time in history, and show that cold fusion might hold the key for really reaching clean energy goals.

In a story by the Financial Times, picked up by Yahoo News and others, said that according to the sources, the government Lawrence Livermore National Laboratory in California had accomplished the net energy gain using an inertial confinement fusion technique, which involves targeting a tiny pellet of hydrogen plasma with the largest laser in the world.

The experiment uses technology that is obviously not practical for creating energy in commercial and industrial environments at present.

But the experiment could mark a major step toward harnessing fusion energy down the road.

The technology’s potential is undeniable. As Yahoo News noted, a modest cup of hydrogen fuel could hypothetically power a house for hundreds of years while producing no carbon emissions or persistent radioactive waste from fusion reactions.

The sources with knowledge of the results claimed that the fusion reaction at the US government facility produced about 2.5 megajoules of energy, which was roughly 120 percent of the 2.1 megajoules of energy in the lasers. They added that the data was still being examined.

Green energy advocates have pervasively overstated claims of technologies like wind and solar. They require intensive processes and have attributes that aren’t environmentally friendly. They are much better suited to some applications than others, and there is little chance that they could supply energy at the levels needed to supplant fossil fuels.

Visual Capitalist argues that practicable fusion energy could be key in augmenting and eventually superseding current so-called green energy technologies, as well as fossil fuels. For more on the U.S. fusion energy breakthrough story, see here.