Households and businesses will be paid to cut their electricity usage as a new scheme goes live.
The National Grid said it would be activating its Demand Flexibility Service on Monday between 5pm and 6pm. The scheme offers people up to £10 a day to cut their electricity usage during peak times, usually between 4pm and 7pm, in order to reduce pressure on the grid.
Simple ways to do this include running energy-intensive appliances such as washing machines and dishwashers outside peak hours.
The scheme also pays larger businesses to reduce demand by using energy outside peak times or relying on generators during periods of high demand.
But the deal relies on smart meters, which are unreliable and have been installed in only half of homes and small businesses. They have also been criticised for malfunctions and inaccurate readings.
People wishing to take part in the scheme have to sign up with a participating supplier, including major firms such as British Gas, EDF, Eon and Octopus Energy. Once you have signed up, your supplier will contact just before the event to confirm that you want to participate.
Craig Dyke, Head of Control at National Grid, told the BBC on Monday that the measures were introduced to “ensure that everyone gets the electricity they need”.
The measures come as the Met Office issued a weather warning about freezing fog. A level-three cold alert will remain in place for England until Wednesday after temperatures plunged below -10C in parts of the UK last week.
Temperatures are expected to drop as low as -2C today and as there will be very little wind, limited electricity will come from wind farms at a time of higher demand from households.