Second Hollandse Kust West Alpha subsea cable in place

Jan De Nul, together with its partner LS Cable & System, has completed the installation of the second subsea cable for the Hollandse Kust West Alpha offshore wind farm grid connection off the coast of Egmond aan Zee for TenneT.


The subsea cable installation was carried out by the cable-laying vessel Isaac Newton, the work vessel Adhémar de Saint-Venant and a remote-controlled cable burial vehicle.

In recent weeks, more than sixty kilometres of cable have been laid in the seabed between the beach of Heemskerk and the “socket” that grid manager TenneT has built at sea.

Last summer, Jan De Nul pulled four sea cables from the beach of Heemskerk in conduits under the dunes. After the installation of the two subsea cables for the Hollandse Kust Nord wind farm, the first kilometres of the two cables for West Alpha were capped and laid in the seabed.

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After the installation of the first sea cable, Jan De Nul brought the capped part of the second cable for West Alpha above the water in April – about five kilometers from the beach.

Following the connection by South Korean cable manufacturer LS Cable & System, the cable was placed back on the seabed. 

At the same time, Jan De Nul’s work vessel Adhémar de Saint-Venant appeared offshore with the unmanned cable-laying vehicle the UTV1200 on board. As soon as Isaac Newton started sailing, the cable slowly unwound from the large turntable on board, followed by the Adhémar de Saint-Venant for the control of the UTV1200, which then laid the cable in the seabed, according to the press release.

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Once the tests are done, TenneT will deliver the connection for West Alpha in the first quarter of 2024.

After that, it will be the turn of operator Ecowende, a joint venture between Shell and Eneco, to build its 700 MW offshore wind farm, so that the turbines can produce energy from wind in 2026.

“From the transformer substation in Wijk aan Zee to our high-voltage substation along the A9 motorway near Beverwijk, all circuits for the three wind farms Hollandse Kust (north), (west Alpha) and (west Beta) have already been tested and are ready for use”, said Thijs den Hammer, project leader on behalf of TenneT.