Storm Angus is suspected to have caused damage to undersea power cables connecting the UK and France, slashing electricity flows through the link by half until the end of February next year.
Citing a statement from the National Grid, The Telegraph said a fault developed on the Interconnexion France-Angleterre (IFA) link between Folkestone and Calais on 20 November.
Four of the eight cables of the link have been severed, possibly by a ship dropping anchor during the storm.
It comes at a time when Britain's capacity margin is already tight and raises fears of a power crunch during the winter.
Storm Angus battered the south coast of England last week, causing widespread flooding and disruption.
The IFA link allows Britain to import up to 2 gigawatts of power from the continent, but damage to the interconnector cables has diminished its maximum capacity to 1 gigawatt until the end of February 2017.
"We experienced a trip of the IFA interconnector on the morning of Sunday 20 November," Power Engineering International quoted the National Grid statement as saying.
"After further investigation, the fault has been identified and we can confirm that four of IFA's eight cables have been damaged. This will result in a reduction of IFA's maximum capacity to 1000MW until the end of February 2017.
"Investigations are ongoing and teams on both sides of the channel are working to restore IFA to full availability. We will issue regular updates regarding progress."
The Telegraph said the damage to the cables was highly unexpected as they are heavily armoured and buried deep within the seabed.
The faults in the cables are believed to be located three miles off the coast at a depth of about 65ft (20m).
Analysts said the problem is likely to drive up the price of electricity over the coming weeks in both Britain and France.