Google is making a big bet on a power source that hasn’t yet been used successfully anywhere in the world: nuclear fusion. The tech company said on Monday that it will buy power from a planned nuclear fusion plant in Virginia developed by Commonwealth Fusion Systems,

Unlike nuclear fission, where atoms are split to release energy, fusion sees atoms forced together. Bob Mumgaard, Commonwealth’s chief executive, said the deal with Google was a “strong signal that the world wants fusion” and that it would support “bringing fusion power to the grid at scale”.