Photographer: Andrew Matthews/PA Images via Getty Images

How a Loose Anchor Cut Up Britain’s Power Link With France

  • Severed section is 5km off British coast and 20m underwater
  • Outage has increased risk of French power cuts this winter

Autumn storms often do damage to Britain’s electricity networks as falling trees bring down local power cables.

Angus, a November 20 gale that brought gusts of more than 80 miles an hour, flooding and localized power cuts, had a more dramatic impact than most. At least one ship pulled off course in the English channel dragged its anchor through a giant power cable linking the U.K. with France, according to people familiar with the matter.

It will take until at least February to repair the power cable, depriving both nations of 50 percent of their mutual import and export capacity. Reduced access to British exports of cheaper electricity has increased the chance of power cuts in France this winter, French grid operator Reseau de Transport d’Electricite SA said Thursday. The grid operator warned last month that it may need to take measures such as rolling blackouts.

The cables are buried under the seabed, so the full extent of the damage isn’t yet known and investigations and repairs will take time. Sonar technology will probably be needed to determine whether some of the cables are completely split, said the people, who asked not to be identified because the information is private. The affected area is 5 kilometers off the British coast at a depth of 20 meters.

Other damage by the storm included a 200-meter cargo ship crashing into a barge near Dover, England. Two coastguard search and rescue helicopters were sent to evacuate crew members, according to the Maritime and Coastguard Agency.

A cargo ship in difficulty in the Channel off the coast of Dover in November.
A cargo ship in difficulty in the Channel off the coast of Dover in November.
Photographer: Gareth Fuller/AP Photo

The interconnector is Britain’s only electricity link with France and can provide as much as 2,000 megawatts in either direction. Four of the cable’s eight components have been severed, according to U.K. network operator National Grid Plc, which owns the link together with RTE. Both companies are working to restore full capacity.

France is typically a net exporter of power to the U.K., but that relationship was reversed last month as extended outages at some of Electricite de France SA’s nuclear reactors cut supply and sent power prices soaring to their highest in almost a decade. The U.K. usually relies on imports when demand peaks during the evening.

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