The World Cup is an opportunity to take a look at how popular football games affect JET’s experimental schedule: JET’s peak power demand is over one percent of the UK supply — albeit for very short periods — so the supply from the grid is limited to 575 megawatts, and JET’s two flywheels are used to top up if necessary. But at some times, JET is not allowed to take any power from the grid at all.
This happens when there are other major energy consuming events — such as halftime in a major football final, or in the ad-breaks in a popular TV show — times at which millions of people will switch on the kettle or go to the toilet, which creates an electrical load on the water pumping system. In fact JET power supply engineers are in regular contact with the grid, who advise every day the times at which pulses should be avoided — for example the fifteen to twenty minutes around sunset when lots of people turn on their lights.
The engineers also monitor the frequency of the electricity supplied by the grid throughout the day: if the frequency falls much below the regulation 50 Hz they know the grid is under load and so they will recommend to the Engineer In Charge that pulses not be run.
Read more on EFDA website.