Households will be paid to put on their washing machines or dishwashers away from peak hours in an effort to prevent blackouts this winter.
However, shortages of gas could mean planned three-hour blackouts in some areas to protect supplies for heating homes and buildings, the UK’s National Grid operator warned.
In the best case scenario, the margin between peak demand and supply will be similar to recent years.
But the National Grid Electricity System Operator (ESO) said the country faces a “challenging winter”.
Europe’s energy supplies are uncertain following Russia’s invasion of Ukraine and so the grid operator is planning for what would happen if there were no imports of electricity from the continent and insufficient gas supplies.
Backup plans include firing up two coal-fired power plants if imports from France, Belgium and the Netherlands fail.
People are being encouraged to sign up with their electricity supplier to a scheme which will give them money back on their bills to shift their use of power away from times of high demand to help prevent blackouts.
That could mean putting on the dishwasher or washing machine overnight or charging an electric vehicle at off-peak times.
In the ESO’s worst case scenario, they assume the UK would run out of enough gas during two weeks in January 2023 when it is both very cold and still meaning low levels of wind power.
If this happened, homes and businesses would be cut off for pre-defined periods – generally for three-hour blocks during the day – the ESO called this “unlikely”.
It said the number of people left without electricity would depend on how many gas power stations would be forced to shut down because there is not enough gas.
But this was the worst-case scenario that the grid operator presented.
To help prevent this, big businesses will be paid to reduce demand by shifting when they use energy or switching to batteries or generators during peak times.
The “demand flexibility service” will run from November to March, and it is expected to swing into action 12 times whatever happens to ensure people get rewarded for being part of the scheme – with additional use if needed to protect supplies.
It is the first scheme of its kind, the ESO’s director of corporate affairs Jake Rigg said, and it is hoped it will deliver 2GW of power savings to balance supply and demand.
Mr Rigg described it as a “smart way for signed up consumers in homes and businesses to save money and back Britain”.
“If you put your washing machine or other electrical appliances on at night instead of the peak in the early evening, you can get some money back when we all need it,” he said.
“The service is due to launch in November, so watch out for further details soon. This really is a window into the future where a flexible energy system will be cleaner and lower cost to alternatives.”
In the ESO’s base case assumes that when Britain needs more electricity, cables that link the country to its European neighbours will be enough to keep the lights on.
It does not assume that there is any “material reduction of consumer demand due to high energy prices”.
Responding to the winter outlook, a Government spokesperson said: “The UK has a secure and diverse energy system.
“We are confident in our plans to protect households and businesses in the full range of scenarios this winter, in light of Russia’s illegal war in Ukraine.
“To strengthen this position further, we have put plans in place to secure supply and National Grid, working alongside energy suppliers and Ofgem, will launch a voluntary service to reward users who reduce demand at peak times.”
The spokesperson said Britain is not dependent on Russian energy imports, and has access to North Sea gas reserves, imports from Norway, and via ports which can handle liquefied natural gas, as well as clean energy sources.