The UK could face planned three-hour power cuts this winter at homes and businesses in case of disruptions in electricity imports from Europe and insufficient gas supply in the country, according to the Winter Outlook report by National Grid Electricity System Operator.

The outlook covers the period of Oct. 31, 2022-March 31, 2023.

According to the base scenario in the outlook, there will be adequate margins of about 3.7 gigawatts through the winter to ensure the UK remains within the reliability standard.

However, there will be days when mitigation measures will be needed to be utilized, given the scale of uncertainty and risks associated with the current geopolitical situation, the National Grid said.

"Notwithstanding the mitigation measures noted, it is highly likely that the wholesale price of energy, both gas and electricity, will remain very high throughout the winter outlook period," it warned.

According to the first illustrative scenario which examines what would happen if there were no electricity imports from Europe, the mitigation strategies would be deployed, including dispatching the retained coal units and a Demand Flexibility Service program.

"By securing 4 gigawatts through these actions, we would maintain adequate margins and mitigate impacts on customers," the National Grid forecasted.

The institution said the Demand Flexibility Service is a new and innovative program to be launched on Nov. 1 by encouraging suppliers and companies to shift their load from peak hours.

"Without the Demand Flexibility Service, we would expect to see a reduction in margins. In this scenario on days when it was cold, therefore likely high demand, with low levels of wind due to reduced available generation, there is the potential to need to interrupt supply to some customers for limited periods of time in a managed and controlled manner," the National Grid said.

According to a second and more extreme scenario, "looking at a hypothetical escalation of the energy crisis in Europe" such that there is insufficient gas supply available in the UK, in addition to no electricity available to import from continental Europe, further eroding electricity supply margins could potentially lead to interruptions to customers for periods.

"In the unlikely event we were in this situation, it would mean that some customers could be without power for pre-defined periods during a day, generally this is assumed to be for 3 hour blocks. This would be necessary to ensure the overall security and integrity of the electricity system across the UK," the operator said.

The outlook also warned that the winter would be challenging across Europe.