In its last hurrah before being shut down, a 40-year-old fusion reactor in the UK set a new world record for energy output — bringing the decades-old promise of clean, limitless energy one step closer to reality.

Scientists at the Joint European Torus (JET) — a huge, donut-shaped machine known as a tokamak — produced a record 69 megajoules of fusion energy for five seconds, surpassing the previous record of 59 megajoules set in 2021. This equates to a power output of 12.5 megawatts, enough to power around 12,000 households.  

The UK’s nuclear minister Andrew Bowie called the latest breakthrough a “fitting swansong” for JET, which concluded its scientific operations at the end of December 2023.