How close are we to achieving practical nuclear fusion energy?

The answer

On December 5, 2022, the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory achieved fusion ignition - producing 3.15 megajoules of 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. Beyond NIF, private companies are advancing rapidly: Commonwealth Fusion Systems plans to complete SPARC, a compact tokamak using high-temperature superconducting magnets, by 2025. TAE Technologies and Helion Energy (backed by Sam Altman) are pursuing alternative approaches. The UK's STEP program aims to build a prototype fusion power plant by the 2040s. The key remaining challenges are achieving sustained reactions (not single pulses) and developing materials that can withstand neutron bombardment over years of operation.