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Denmark and the UK are now officially connected through the world’s longest power cable

Today, the world’s longest power cable, Viking Link, was officially inaugurated at locations at Lincolnshire in the UK and South of Jutland in Denmark respectively. Connecting Denmark with the UK, the interconnector marks the road ahead of international collaboration on advancing renewable energy initiatives and interconnected energy systems.

Photo credit: Energinet

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

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.

Discover the case

Thursday marked the official “pressing of the button” for the world’s longest electricity cable connection, Viking Link, between Denmark and the United Kingdom. The Danish system operator Energinet and the British National Grid’s joint investment of 13 billion Danish kroner represents a significant piece in the green transition of the energy system.

This happened at a festive ceremony on Thursday – in fact, at two ceremonies in Revsing in South Jutland and Bicker Fen in Lincolnshire, United Kingdom.

Already at the end of December 2023, the first electrons of Danish green power were sent through Viking Link to English sockets. The first three months of 2024 have been a ramp-up period for the connection and, as expected, the traffic through the 765-kilometre-long cables has moved significantly more towards the west than towards the east in January, February, and March: In the first three operational months, Denmark has exported electricity 80 percent of the time. In addition to this, Viking Link has already earned approximately 20 million euros (to be split equally between Energinet and National Grid). This money benefits Danish electricity consumers since Energinet can use the revenue to invest in the Danish electricity system (funds that would otherwise have to be collected through tariffs).

“The establishment of Viking Link marks a huge milestone in our efforts for the green transition of our energy system. Not only the Danish but also the European one. Since we sent the first electrons through the cable at the end of December last year, we have sent large amounts of electricity to our English friends, thereby ensuring that the green power from Danish solar cells and wind turbines is used most effectively. The connection, and electrical interconnections in general, also contribute to our supply security, and the value of this type of connection cannot be underestimated in a world where supply security is not guaranteed.” Thomas Egebo, CEO of Energinet

Also read: The world’s longest power cable is switched on, connecting Denmark with the UK

A step towards an interconnected Europe

The Danish part of the inauguration on Thursday took place at Viking Link’s Danish “anchor,” the converter station in Revsing in Vejen Municipality. Here, Thomas Egebo greeted his British colleague, Katie Jackson from the partner company National Grid, via a direct video link, thanking her for the cooperation with Viking Link over the past 13 years. And after a short countdown and pressing the button, he declared Viking Link inaugurated – in the presence of around 150 invited neighbours and special guests.

“Creating an electricity connection between Denmark and England is in itself a huge achievement. But it has also been a long and tough journey to get here due to external reasons. Challenges such as Brexit, the corona pandemic, the Ukraine war, energy crisis, Suez Canal blockage, Rhine drought, raw material shortages, and delivery problems. All things that have affected the project along the way, and yet we finished on time, with a beautifully completed work. I am enormously proud of the work and approach that our project team has carried out, along with our partners and contractors, and I am really happy that we can now celebrate a job well done today.” Thomas Egebo, CEO of Energinet

Denmark already has electricity connections to Norway, Sweden, Germany, and the Netherlands. With Viking Link, Danish producers can sell and export electricity to yet another neighbouring country when it’s windy and sunny. Conversely, in Denmark, we can now also buy electricity when there is plenty on the other side of the North Sea. For instance, if a wind front from the west hits the United Kingdom a day before it hits the Danish wind turbines.

Discover the case: The Cobra Cable: unleashing green energy between the Netherlands and Denmark

Currently, Viking Link runs with limited capacity. But when the Danish electricity grid is fully ready to utilise Viking Link’s full capacity of 1400 MW in 2025, the connection will be the largest single component in the Danish electricity system.

In addition to utilising and transporting green electricity, Viking Link also provides a significant benefit for the climate: During its first year at full capacity, Viking Link is expected to save 600,000 tons of CO2, primarily in the United Kingdom. This is equivalent to removing 280,000 petrol or diesel-powered cars from English roads.

Viking Link: the world's longest interconnector

Viking Link is the new 765 km long electricity interconnector between Denmark and Great Britain. The interconnector will enable more effective use of renewable energy, access to sustainable electricity generation, and improved security of electricity supply.

Learn more about Viking Link

Facts on the Viking Link

  • Viking Link is a 765-kilometer-long direct current cable, installed both on land (135 km) and as a submarine cable (630 km).
  • The cables are connected to two converter stations – one in Revsing near Vejen in Denmark, and one on the English side at Bicker Fen in Lincolnshire.
  • The converter stations are designed to convert the direct current (DC) running through the cable into alternating current (AC), which runs in the domestic electricity grids in both countries.
  • The cable is installed in sections of 1.5 kilometers on land, while it is installed on the seabed of the North Sea in seven segments of nearly 100 kilometers each.
  • The cable is constructed using the MIND method (Mass Impregnated, non-Draining), which involves copper cables impregnated with materials such as paper and oil. This type of cable is well-suited for use in connections that need to withstand harsh weather conditions and high voltage (525 kV).
  • The cable connection consists of two parallel cables along the entire route. Each cable weighs nearly 50 kg per meter. The drums with the land cables, each containing 1500 meters of cable, weighed 80 tons.
  • Since 2019, when the construction phase of the Viking Link project began, more than four million man-hours have been spent establishing the connection.
  • Viking Link’s station in Revsing is a high-voltage station. This means that the equipment at the facility is voltage-sensitive and hazardous to personnel, and access to much of the facility is restricted to the highest standards. This applies to both the public and Energinet’s technicians. The station is therefore unmanned.
  • The first opportunity to enter the live halls is two years after commissioning, and access is via an interlocking system. This means a key system that requires multiple steps at multiple locations, and you need a key to proceed to get the next key (similar to the TV series Fort Boyard).
Learn more about Viking Link

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