Britain's National Grid is responsible for overseeing the country's energy supply and making sure supply and demand are evenly balanced.
"While we remain confident there is sufficient supply to meet peak demand, we should prepare for some tight periods during the winter," National Grid's Electricity System Operator (ESO) said in an early winter outlook published on Thursday.
National Grid ESO forecast its underlying average cold spell electricity peak demand at 59.5 GW which "assumes that there is no suppression of peak demand in Winter 2021/22 due to the ongoing COVID-19 pandemic," the report said.
National Grid ESO said its base case for de-rated margin, which is a measure of the amount of excess capacity expected above peak electricity demand, is currently 4.3 gigawatts for Winter 2021/22, or 7.3% of capacity.
It said this was slightly lower than last year but well above margin parameters requested by the government.
National Grid ESO said it had published early indications of demand to help the industry better prepare for the winter months. A full outlook for Winter 2021/22 will be published in October.
(Reporting by Susanna Twidale; Editing by Edmund Blair and David Evans)