THE head of the National Grid has warned that blackouts could be imposed between 4pm and 7pm on “really, really cold” winter weekdays if gas imports are reduced. 

John Pettigrew, the National Grid chief, said blackouts would be in place during the “deepest darkest evenings” in January and February should electricity generators not have enough gas to meet demand. 

His comments came at the Financial Times’s Energy Transition Summit on Monday. 

Earlier this month, the National Grid had put the country on notice that the chances of gas shortages in winter have risen and that planned three-hour blackouts could be imposed in some areas. 

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Following the first announcement, Nadhim Zahawi said blackouts were an “extremely unlikely scenario”. 

This is the first time since that warning that there has been explicit discussion over what time blackouts could possibly occur. 

Pettigrew said the National Grid had not changed its “base case” that there would be sufficient gas and power to meet demand. 

However, he added: “In the context of the terrible things that are going on in Ukraine and the consequences of that [it was] right that we set out what some of the potential risks could be.”

Britain does not rely on Russia for gas although normally draws on European supplies to keep power stations running. 

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Pettigrew said January and February are the months when blackouts are most likely. 

He said the situation could potentially grow worse if wind speeds happen to be low, reducing the effectiveness of power turbines while energy imports were restricted.

He added that there was a “huge amount of work” being done by energy suppliers, regulators and officials to ensure vulnerable households receive the support they need. 

Numerous measures are planned to avoid blackouts. This includes placing coal-fired power stations on standby and the creation of a service which would allow consumers to be rewarded for not using power during times of peak demand.