National Grid puts coal plants on standby to supply electricity

Three UK coal plants have been ordered to begin warming up in case they are needed as the cold snap continues.

National Grid ESO said it had asked power station operator Drax to prepare two coal-fired units and EDF to warm up its West Burton plant.

A scheme that offers discounts for households who cut peak-time energy use is also set to be triggered.

National Grid ESO said the measures were "precautionary" and it did not mean electricity supplies were at risk.

The company said that it expected electricity supply margins to be "tighter than normal" on Monday evening.

However, it added that "people should not be worried" by the measures.

"These are precautionary measures to maintain the buffer of spare capacity we need," it said.

The cold weather means demand for energy rises as more people heat their homes, but a lack of wind has reduced the amount of renewable energy available.

National Grid ESO also said that between 17:00 and 18:00 GMT it would activate a scheme that allows some households to receive discounts if they cut their use of electricity, by, for example, delaying the use of a tumble-dryer or washing machine.

The scheme, called the demand flexibility service, is available to homes with smart meters and whose energy supplier is signed up to it.

According to National Grid ESO, 26 suppliers have joined the scheme, including firms such as British Gas, EoN, Octopus Energy and EDF, and more than a million households and businesses have now signed up to take part.

The scheme is scheduled to run until March and until now has only been used in tests.

John Pettigrew said National Grid's "base case" assumption was the UK would have enough supplies to meet heating and lighting demand.