Six million homes could face power cuts this winter as ministers draw up plans for rationing should the Russia-Ukraine war continue to escalate.
Government modelling of a “reasonable” worst-case scenario predicts major gas shortages in winter if Russia cuts off more supplies to the EU, according to The Times.
Limits could be slapped on industrial use of gas, including on gas-fired power stations, causing electricity shortages.
As a result, six million homes could see their electricity rationed, primarily during morning and evening peaks, in curbs that may last more than a month.
Worse modelling is reported for a scenario in which Russia cuts off all supplies to the EU.
It comes after Chancellor Rishi Sunak unveiled new £15 billion cost of living support package to help households facing rocketing energy bills.
A Department of Business, Energy and Industrial Strategy spokesperson said the UK "has no issues with either gas or electricity supply, and the Government is fully prepared for any scenario, even those that are extreme and very unlikely to pass".
"Thanks to a massive £90 billion investment in renewable energy in the last decade, we have one of the most reliable and diverse energy systems in the world," the spokesperson added, "and unlike Europe, we are not dependent on Russian energy imports."
But threats to security of supply have prompted Business Secretary Kwasi Kwarteng to ask Britain's coal-fired power stations to delay their planned closures.
Power stations in Drax, Ratcliffe and West Burton, which were due to shut in September, were asked to to stay open following the Russian invasion of Ukraine.
Technology Minister Chris Philp said these were "sensible precautionary measures to guard against a potential worst case scenario".
The Business Secretary is also considering whether to extend the life of Hinkley Point B, a nuclear power station in Somerset which was due to be decommissioned in the summer.
Mr Philp told TimesRadio: "That's a sensible precautionary measure, given that gas supply coming out of Russia, and Ukraine is for obvious reasons, so heavily disrupted and we do, of course, use quite a lot of gas to generate electricity.
"Only a very small proportion of that, of course, comes from Russia, a lot of ours comes from Norway and in the form of liquefied natural gas.
"But of course, disruption to the global gas market will have a knock on effect that may affect the gas that we consume domestically in the United Kingdom.
"So I think these are just sensible precautionary measures, just to guard against a potential worst case scenario."
Boris Johnson's deputy spokesman did not rule out power cuts and energy rationing but said these were plans for the worst case scenario.
He said: "I think you would expect Government to look at a range of scenarios to ensure plans are robust, no matter how unlikely they are to pass. Neither the Government or National Grid expect power cuts this winter.
"You will know that we are in a fortunate position, we are not dependent on Russian energy imports and have one of the most reliable and diverse energy systems."
