How close is nuclear fusion to becoming a commercial energy source?

The answer

On December 5, 2022, the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory achieved nuclear fusion ignition for the first time in history - producing 3.15 megajoules of fusion energy from 2.05 megajoules of laser input, a net energy gain of 54%. This was repeated and surpassed in subsequent shots in 2023, with one producing 3.88 MJ. The achievement proved that controlled fusion energy gain is physically possible on Earth. Beyond government research, private fusion companies have raised over $6 billion: Commonwealth Fusion Systems (backed by Bill Gates) plans its SPARC compact tokamak demonstration by 2025, Helion Energy (backed by Sam Altman) targets electricity generation by 2028, and TAE Technologies pursues proton-boron fusion. The international ITER project in France - a $22 billion collaboration of 35 nations - aims to demonstrate sustained 500-megawatt fusion output by the late 2030s. Most experts project commercial fusion reactors producing grid electricity by 2035-2040, though skeptics note fusion has been '30 years away' for 60 years. The key remaining challenges include sustaining reactions continuously (not just single pulses), developing materials that withstand intense neutron bombardment, and achieving economic viability against increasingly cheap renewable energy.