System operator National Grid can use a number of ways to control the supply of electricity if there is a spike in demand:
- It can lower the voltage, which means households may notice lights dimming or flickering
- Industrial customers can also be asked to come off the supply to protect households
More top news
Fresher and cooler as we head into the second half of the weekend.
Leah Washington, 17, had to have her left leg amputated after being trapped for hours on The Smiler rollercoaster at the theme park.
The video, obtained by ITV News, shows scores of migrants desperately trying to board lorries in a restricted area within the tunnel.