The head of the National Grid has warned British households that blackouts may be imposed between 4pm and 7pm on “really, really cold” winter weekdays if Europe cuts gas exports.
John Pettigrew said electricity and gas may be switched off on “those deepest, darkest evenings in January and February” if energy supplies from Europe prove insufficient due to the disruption of the war in Ukraine.
Countries across Europe have been left unable to rely on Russia for their gas as the colder months approach and, despite rationing, analysts said further cuts from Moscow could leave the continent short of supplies.
Mr Pettigrew’s comments, made at the Financial Times’s Energy Transition Summit, came after the National Grid this month set out several “unlikely” scenarios in which Britain would run low on supplies.
He said the National Grid had not changed its “base case” there would be sufficient gas and power to meet demand in Britain this winter. But 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 but normally draws on European supplies to keep its power stations running in the coldest months.
Mr Pettigrew said January and February are the months when blackouts are most likely, particularly in a cold snap.
He said the situation could be even worse if wind speeds happen to be low, cutting the effectiveness of power turbines while energy imports were restricted.
In the “worst case” circumstances, power would be cut off to parts of the country for up to three hours “probably between 4pm and 7pm in the evenings on those weekdays when it’s really, really cold in January and February”, Mr Pettigrew said.
He said there was a “huge amount of work” being done by energy suppliers, the regulator and officials to ensure vulnerable households in particular received support should it become necessary to impose blackouts.
The government has flip-flopped on whether to encourage the public to save energy over winter.
Liz Truss has ordered a public information campaign on cutting power use despite rejecting earlier plans for being too interventionist.
Under the plan being developed by Jacob Rees-Mogg, the energy secretary, people and businesses will be told how to “use energy more efficiently”.