If Britain is unable to import enough energy, it could face rolling blackouts in the winter.
National Grid warned that electricity supplies could run out, and households and businesses may be without power for as long as three hours per day.
To ensure that power doesn’t drop further, some areas would have their electricity cut.
If supplies are tight, consumers will be expected to accept payments to reduce their energy consumption at peak times.
To help compensate for imbalances, coal-fired power plants will be kept online for longer periods than originally planned.
This comes as Russian gas supplies to Europe have been cut due to its war against Ukraine, causing havoc on the gas and electricity markets.
France’s electricity supplies are also constrained by outages to its nuclear fleet.
National Grid calls the possibility of insufficient gas supplies “unlikely”, but states that the winter will be “challenging” so it is important to prepare.
Fintan Slye is the executive director of National Grid’s electric system operator. He is responsible for balancing Britain’s electricity supplies.
He added that he was an expert and responsible operator for Great Britain’s electricity grid and it was his responsibility to consider external factors and risks beyond our control, such as the unprecedented volatility and turmoil in European energy markets and elsewhere.
National Grid provides an annual outlook of gas and electricity supplies for the year ahead of winter, to assist industry and consumers in preparing.
The electricity system operator stated in documents that it believes that Britain will have sufficient electricity to supply demand, including buffer supplies.
This assumes, however, that Britain can import from Europe when necessary.
It also models scenarios in which it can’t import enough electricity from Europe and where it cannot purchase enough gas.
This could be due to gas shortages in Europe, or continuing outages at continental power plants.
National Grid will switch to five coal-fired plants owned by Uniper, EDF and other companies in the first scenario. These plants have been requested to remain online past their scheduled September closures.
It will also be using a new scheme that will run from November through March. This will allow households and businesses to agree in advance to receive payments to temporarily stop using electricity if necessary.
It means that households are paid to use their washing machines, and charge their electric cars away during peak hours or shifts in factories.
National Grid anticipates being able to secure approximately two gigawatts of lower demand, enough to power roughly 600,000. This scheme could impact large businesses as well as hundreds of thousands of households.
However, if the scheme does not provide the savings needed on a cold day it might need to “interrupt supply for some customers for limited times”.
National Grid examined the possibility of ten gas-fired power stations being unable to function in the second scenario, where there is not enough electricity or gas.
It states that “Should such a scenario occur, it may be necessary for the planned controlled and temporary load-shedding scheme.”
“In the unlikely case that we were to find ourselves in this situation, it could mean that customers would not have power for pre-defined periods of time during the day. Generally, this is for three-hour blocks.
“This would be necessary in order to ensure the security and integrity across the entire system throughout Great Britain.”
South Africa is a frequent user of load-shedding, which means that households and businesses are regularly without power due to problems at the state utility Eskom.
However, power is not always cut in all areas at once. Instead, it is distributed throughout the day.
National Grid also highlighted the importance of gas supplies in a separate outlook. It highlighted the need for natural gas imports from all over the globe to balance the supply.
Director of gas system operations Ian Radley stated that “Great Britain is able to access a variety of flexible and diverse sources of natural gas, supported with flexible infrastructure.”
