Householders will be paid to use less electricity today as three coal plants were ordered to begin warming up in case they are needed for the country's energy supply.
National Grid ESO said it had given the instructions after forecasts showed electricity supply margins may be tighter than normal on Monday. It has also activated a live "demand flexibility service" between 5pm and 6pm today.
This scheme allows the ESO to access additional flexibility when national demand is at its highest during peak winter days. It entitles some households with smart meters to discounts if they cut their use of electricity.
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It is due to stay in place until March, with 26 energy suppliers including Octopus Energy and EDF signed up to it, but until now has only been used in tests. National Grid ESO added that its announcement should not be interpreted as a sign that electricity supplies are at risk and said "people should not be worried".
On Sunday night, National Grid ESO said on Twitter: "Our forecasts show electricity supply margins are expected to be tighter than normal on Monday evening. We have instructed coal-fired power units to be available to increase electricity supplies should it be needed tomorrow evening.
"We are also activating a Live DemandFlexibilityService event between 5-6pm tomorrow. This does not mean electricity supplies are at risk and people should not be worried. These are precautionary measures to maintain the buffer of spare capacity we need."
The cold weather means more people are heating their homes which increases demand for energy, but a lack of wind has reduced the amount of renewable energy available.
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