National Grid has warned that households and businesses could be cut off for periods of time if electricity supplies run short.

The electricity would be cut off in some areas of the country to ensure power does not go down more widely.

Consumers will also be relied on to accept payments to cut their energy usage at peak times if supplies are looking tight.

Households could be paid more than £10 a day for reducing their energy use. National Grid plans to use the scheme at least 12 times even without energy shortages to encourage people to take part.

Coal-fired power plants are also being kept online longer than planned to help cover imbalances.

It comes as cuts to Russian supplies of gas to Europe amid its war on Ukraine have wreaked havoc on gas and electricity markets.

Supplies of electricity from France are also strained due to outages on its nuclear fleet.

National Grid describes the prospect of insufficient gas supplies as “unlikely” but says the winter is likely to be “challenging” and it needs to be prepared.

Fintan Slye, executive director of National Grid’s electricity system operator, which is in charge of balancing Britain’s electricity supplies, said he was “cautiously confident” there would be adequate supplies this winter.

But he added: “As an expert and responsible operator of Great Britain’s electricity system it is incumbent on us to also factor in external factors and risks beyond our control like the unprecedented turmoil and volatility in energy markets in Europe and beyond.”

National Grid produces annual outlooks of electricity and gas supplies ahead of winter to help industry and consumers prepare.

In the documents published today, the electricity system operator says its “base case” is that Britain will have enough electricity to meet demand including buffer supplies.

However, this assumes that Britain can import from the continent when it needs to.

It has also modelled scenarios in which it cannot import enough electricity from Europe, and in which it cannot buy enough gas.

This could happen for example due to gas shortages in Europe or continued outages on continental power plants.

In the first scenario, National Grid will turn to five coal-fired power plants, owned by EDF, Uniper and others, which have been asked to stay online beyond planned closure dates this September.

It will also use a new scheme, which will run from November to March, in which households and businesses can agree in advance to be paid to stop using electricity temporarily if needed.

In practice it means households being paid to put on their washing machines or charge their electric cars away from peak hours, or factories to shift hours.

National Grid expects to be able to secure about two gigawatts of reduced demand – enough to power about 600,000 homes. The scheme could involve hundreds of thousands of households as well as large businesses.

But if the scheme did not deliver the savings required on a cold day, it may need to “interrupt supply to some customers for limited periods of time”.

In the second scenario of insufficient supplies of both electricity and gas, National Grid has looked at what would happen if ten gas-fired power plants were unable to operate as a result.

“Should this scenario happen it may be necessary to initiate the planned, controlled and temporary rota load-shedding scheme,” it says.

“In the unlikely event that we were in this situation, it would mean that some customers would be without power for pre-defined periods during a day – generally this is assumed to be for three hour blocks.

“This would be necessary to ensure the overall security and integrity of the system across Great Britain.”

Load-shedding is frequently used in South Africa, where problems at state utility Eskom mean businesses and households routinely have the power switched off.

All areas are not cut off at the same time, but power cuts are shared out across the day.

In a separate outlook looking at gas supplies, National Grid highlights the importance of shipments of natural gas imported from around the world to balance supplies.

Ian Radley, director of gas system operations, said: “Great Britain benefits from access to a range of diverse and flexible sources of gas, supported by flexible infrastructure.”