Belgium and Denmark exploring subsea power link

Belgian system operator Elia and its Danish counterpart Energinet have launched a feasibility study for a subsea cable between the two countries that would link the high-voltage grids over a distance of more than 600 kilometres.

The TSOs plan to wrap up the study by the end of 2021, with a ‘hybrid’ design in mind.

Namely, on the Danish side, the interconnector would link a new planed ‘energy island‘ 80 kilometres off the Danish coast and to which a large 10 GW wind farm will eventually be connected.

The start of the feasibility study follows the political cooperation agreement signed by the Belgian and Danish Energy Ministers, Tinne Van der Straeten and Dan Jørgensen.

The project dovetails with the implementation of the European Green Deal, which aims for Europe to become the first climate-neutral continent by 2050 by increasing the current capacity of 25 GW offshore wind to 300 GW.

Transmitting electricity generated offshore to onshore consumption centres requires a meshed subsea electricity grid in which hybrid interconnectors are key components, Elia says.

“Building the Belgian-Danish cable is an important next step in making our electricity system more sustainable. It will be the first time our country is connected to a new electricity market that is further away than our neighbouring countries.

“Thanks to hybrid technology, we will also gain direct access to large wind farms in the far northern part of the North Sea where the meteorological conditions are different from those off the coast of Belgium. This will provide greater security of supply and will help our energy-intensive industry to continue decarbonising.

Elia and Energinet already have experience with subsea HVDC (high-voltage direct current) interconnectors. In early 2019, Elia commissioned Nemo Link, Belgium’s first subsea interconnector with the United Kingdom. In late 2020, Energinet – together with Elia’s German subsidiary 50Hertz – built the Combined Grid Solution, the world’s first hybrid interconnector between Denmark and Germany.

The collaboration between Energinet and 50Hertz may lead to additional projects.

A working group is investigating the possibility of a second hybrid interconnector in the Baltic Sea. The cables would also connect to offshore wind farms via a link to Denmark’s Bornholm Energy Island.

“Belgium will be a completely new neighbour for Denmark. With this project, we can build on our good and innovative cooperation with Elia’s German subsidiary, 50Hertz,” Thomas Egebo, CEO Energinet

When the interconnector between Belgium and Denmark is completed, the cable will run through the territorial waters of four countries: Belgium, the Netherlands, Germany and Denmark.

It could become the longest subsea direct-current (HVDC) cable in the world.