With over sixty kilometres of sea cable on board, the cable-laying vessel Isaac Newton will appear off the coast of Heemskerk/Wijk aan Zee this week. With this cable section, the contractor combination Jan de Nul Group/LS Cable & System is realising the second connection for the offshore wind farm Hollandse Kust (west Alpha) to TenneT’s ‘socket at sea’ 50 km off the coast of Egmond aan Zee. This wind farm’s first sea cable connection was completed earlier this year.
About five kilometres from the beach, Jan de Nul will bring the first part of the second cable for ‘west Alpha’ to the surface. This cable was already pulled under the dunes last year, after which the first kilometres were laid in the seabed. On board the Isaac Newton, the end (currently still capped) will be connected to the cable on board by means of a so-called sleeve connection.
In the seabed
Once the connection has been made, the cable is placed back on the seabed. At the same time, the work vessel Symphony from the Belgian contractor’s fleet appears off the coast. On board is the unmanned cable-laying vehicle Swordfish. Once the Isaac Newton sets sail, the sea cable will slowly unwind from the large turntable on board. The Symphony sails behind it to control the Swordfish, which then lays the cable into the seabed.
Socket at sea
The cable is installed up to the site where TenneT is having the offshore transformer platform for the ‘west Alpha’ wind farm built. For this, at a distance of some 50 kilometres off the coast of Egmond aan Zee, the undercarriage is already on the seabed. This summer, the ready-made superstructure will be placed on top of it. TenneT will soon bring energy from the sea to land through this grid connection.
The ‘west Alpha’ wind farm, which will be realised and operated by Ecowende (a joint venture between Shell and Eneco), will soon consist of 54 wind turbines with a combined capacity of 756 megawatts. That is enough renewable energy to meet about 3% of the current Dutch electricity demand. That corresponds to the consumption of one million households. The wind farm is expected to be fully operational by 2026.
Image source: Courtesy of TenneT
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