Jan De Nul, LS Cable install first Hollandse Kust West Alpha sea cable

Jan De Nul and LS Cable & System have completed the installation of the first sea cable for TenneT’s Hollandse Kust West Alpha substation in the North Sea off the Dutch coast.

TenneT/Flying Focus

In recent weeks, the cable-laying vessel Connector and the remote-controlled cable-laying vehicle UTV1200 laid more than 60 kilometres of cables between Heemskerk beach and the undercarriage (jacket) for the Hollandse Kust West Alpha.

Jan de Nul’s Connector, carrying over 60 kilometres of marine cable on board, appeared off the coast of Heemskerk/Wijk aan Zee in mid-December. This cable section completed the first connection up to TenneT’s Hollandse Kust West Alpha, according to the Dutch-German grid operator.

Earlier last year, Jan de Nul pulled the two sea cables for West Alpha from the Heemskerk beach into the jacket pipes under the dunes and the first kilometres of cables were laid capped in the seabed.

Some five kilometres from the beach, Jan de Nul pulled up the capped section of the first cable for West Alpha in mid-December. On board the Connector, the end was then connected to the cable on board.

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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 the Connector set sail, the cable slowly unwound from the large turntable on board. Followed a short distance away by the Adhémar to control the UTV1200, which then laid the cable into the seabed, TenneT said.

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In August 2022, the jacket for TenneT’s transformer platform was anchored to the seabed 50 kilometres off the coast of Egmond op Zee. 

Here, the first cable was successfully retracted through the cable deck in recent days. Next spring, Jan de Nul, using the cable-laying vessel Isaac Newton, will retrieve the remaining section for the second sea cable in South Korea so that this cable section can be installed.

In the summer of 2023, TenneT plans to have the topside installed on the jacket so that the grid operator can bring renewable wind energy ashore via this substation from next year.

With a capacity of 700 MW, the amount of renewable energy brought ashore corresponds to 2.5 per cent to 3 per cent of current consumption in the Netherlands.