World’s longest subsea power cable connects Britain to Denmark

On December the 29^th the Viking Link went online, enabling Britain to begin trading electricity with Denmark.  The Viking Link is the world’s longest undersea power cable, spanning 760 km across the North Sea to connect Lincolnshire to southern Jutland in Denmark.  It will transmit up to 0.8 GW of power until upgrades to Denmark’s transmission grid unlock its full capacity of 1.4 GW.

Denmark is comparable to Scotland in terms of population, with 5.9 million versus 5.5 million people.  Wind is by far its largest source of generation, supplying almost two-thirds of electricity.  This is enabled by a well-connected grid, with large interconnections to neighbouring Norway, Sweden and Germany.

In its first days, the Viking Link sent an average of 660 MW to Britain, with us importing every hour since it went live.  Britain already has the 2^nd largest trade deficit for electricity across Europe.  It imported 33 TWh and exported 10 TWh during 2023, giving a 23 TWh net shortfall of generation – second only to Italy. 

This new interconnector stands to further increase our reliance on foreign imports.  However, it is expected to save UK consumers around £50 million per year by increasing access to cheaper power sources abroad.  Last year, Danish electricity prices averaged £20/MWh lower than in Britain.  The link should also benefit Britain’s renewables  by giving more options to export when output is high.

Net trade of electricity between European countries in 2023

Electricity trade between Britain and neighbouring markets during 2023.