In a first-of-its-kind agreement, Google will purchase electricity from a nuclear fusion power plant. But the technology remains years from commercial scale.

Google on Monday announced a groundbreaking agreement with Commonwealth Fusion Systems (CFS) to purchase 200 megawatts of clean fusion electricity from the company’s first commercial power plant, ARC.

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,