Fusion ignition happened in 2022. Grid-scale energy: median bet, 2046.

On December 5, 2022, the National Ignition Facility achieved fusion ignition — more energy out of the fuel pellet than the lasers put in. It was the first demonstration of net energy gain from controlled fusion in human history. It was also one shot, in a building-sized laser, into a fuel pellet that cost more than the energy it produced. The path from physics demonstration to grid-scale fusion power runs through engineering, supply chains, and capital that don't yet exist. The Manifold prediction market's median estimate for the first commercial fusion reactor producing net grid energy is 2046.