Cable-laying vessel Isaac Newton, multipurpose vessel Adhémar de Saint-Venant and a remotely-controlled cable burying vehicle of consortium Jan De Nul Group-LS Cable & System have completed the installation of the second marine cable for the offshore wind farm ‘west Alpha’. In recent weeks, more than 60 kilometres of cable was laid and buried in the seabed between Heemskerk beach and the ‘socket’ that grid operator TenneT is having built at sea.
Caption: Multipurpose vessel Adhémar de Saint-Venant remotely controlled the underwater robot UTV1200 that buried the cable in the seabed.
Last summer, Jan De Nul pulled four sea cables from Heemskerk beach in jacket pipes below the dunes. After the installation of the two sea cables for the Hollandse Kust (noord) wind farm, the first kilometres of the two cables for ‘west Alpha’ were laid under the seabed. Following the successful installation of the first ‘west Alpha’ sea cable earlier this year, Jan De Nul brought the free end of the second cable for ‘west Alpha’ to the surface in April – some five kilometres from the beach.
After jointing by the team from partner LS Cable & System, the cable was placed back on the seabed. At the same time, the multipurpose vessel Adhémar de Saint-Venant arrived on site with the unmanned cable-laying vehicle UTV1200 on board. As soon as the Isaac Newton set sail, the cable slowly unwound from the large turntable on board; later followed by the Adhémar de Saint-Venant to control the UTV1200, which then buried the cable in the seabed. Adhémar de Saint-Venant also installed scour protection where the cable crossed other submarine connections.
Thijs den Hamer, Project Manager at TenneT, looks back on this part of the project with satisfaction: “With the installation of the sea cables for the wind farms ‘noord’ and ‘west Alpha’, the contractor delivered a fine performance within the envisaged schedule. After the summer, we will have the ready-made superstructure (topside) installed on the undercarriage, after which we can test the cable connections.”
Glenn Severs, Offshore Construction Manager at Jan De Nul Group: “We at Jan De Nul are very proud to deliver this project perfectly on schedule together with our partner LS Cable & System. After the successful completion of all works on and in front of the beach last year within one summer season, this year we are delivering the remaining part of the export cables for the Hollandse Kust (west Alpha) project within the targeted schedule. Now that all cables are safely buried at depth, the wind farms can be connected and the Netherlands can be supplied with additional green power.”
