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Viking Link: Exchanging green energy flows via the world’s longest power cable

23. January 2024

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Energinet is an independent public enterprise owned by the Danish Ministry of Climate, Energy and Utilities. We own, operate and develop the transmission systems for electricity and natural gas in Denmark.

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The transition from fossil fuels to renewable energy sources is crucial in the global push towards decarbonisation. All across the world, countries are actively striving to establish a sustainable supply of green energy in order to reach net zero emissions by 2050. However, to sustain an energy system centered on renewables, governments must prioritise ensuring cost-effective, uninterrupted power flows in order to maintain widespread support for energy systems built around renewables. 

With these challenges in mind, the UK and Denmark teamed up to connect the two countries’ energy grids by building the world’s longest interconnector named “Viking Link”.


Viking Link: The world’s longest interconnector 

  • Viking Link stretches 765 km across the North Sea, making it the longest power cable in the world exchanging green energy between the UK and Denmark 
  • The project is a joint venture between the National Grid from the UK and Danish system operator, Energinet 
  • Viking Link can provide enough electricity to power 2.5 million homes 
  • Expected to save approximately 600.000 tonnes of carbon emissions – equivalent to taking roughly 280.000 cars off the road. 
Learn more about Viking Link

Beginning back in 2019, the Viking Link project involved intricate construction of converter sites, onshore and offshore cable installations, and their connection to substations of the shores of both Denmark and the UK. The 1400 MW high voltage direct current (DC) electricity link of the cable seamlessly integrates the British and Danish transmission systems at key substations in southern Jutland, Denmark, and Lincolnshire, England, respectively. 

Viking Link, which is a partnership between the British National Grid and the Danish system operator, Energinet, enables surplus energy generated from wind turbines and solar cells to be exchanged and not go to waste, providing access to a broader energy mix for both Denmark and the UK. The interconnectors provide an effective way to manage fluctuations in supply and demand, thus supporting the use of renewable energy. 


On 29 December 2023, the switch was turned on enabling the first green electricity to flow between the UK and Denmark. Stretching a record 756 km across the North Sea, Viking Link is the world’s longest land and subsea interconnector.  


Viking Link: the world's longest interconnector

Viking Link plays a crucial part in the EU’s strategy to secure energy supply, by ensuring reliable, clean and affordable energy for both Denmark and Great Britain. The interconnector will enable more effective use of renewable energy, access to sustainable electricity generation and improved security of electricity supplies, while also adding socioeconomic benefits for both countries. The implementation paves the way for a greener, interconnected energy system in the future.  

Publication: The Polish-Danish energy tie-up

This case is a part of the publication: “Polish-Danish energy tie-up: Tangible ways to double down on energy efficiency in Poland and the rest of Europe”

Discover the publication