Beta jacket for offshore power socket Hollandse Kust (zuid) installed
Wednesday 30 June 2021
The second jacket of TenneT's offshore transformer platform for the wind farm Hollandse Kust (zuid) has arrived at its final destination and has been installed, some 22 kilometres off the coast of The Hague. The 2,852-tonne heavyweight was placed on the bottom of the North Sea by a special lifting vessel (the Sleipnir) of the Dutch company Heerema, on behalf of main contractor Petrofac. The jacket left the fabrication yard end of May in the United Arab Emirates, where it was built. The jacket is the foundation on which the transformer platform will be placed. The connection for the wind farms will be ready for use in 2022.
Foundation
The jacket is 50 metres long, 34 metres wide and 44 metres high and is anchored to the seabed by six piles, each weighing 162.5 tonnes. The 57.7 metre long piles were drilled 46.5 metres into the seabed. The jacket was then attached to the piles. Together, this forms the foundation for one of the two transformer stations for the wind farm Hollandse Kust (zuid). The transformer platforms will have a capacity of 700MW each. The first jacket for the Hollande Kust (zuid) wind farm has been installed in the North Sea in September last year. The wind farm is developed by Vattenfall, in co-ownership with BASF.
The superstructure (or topside), the transformer station itself, will be lifted onto the first jacket at the end of this year. The topside of the second jacket is expected to follow early next year. Once the topsides have been lifted onto the jacket, the last systems will be connected, tested and put into operation. The cables of the wind turbines will then be connected and the wind farm is expected to be fully operational in 2023.
Milestone
The installation of the second jacket is an important milestone for TenneT. "The past year has been characterised by uncertainty and challenges due to the COVID pandemic. Not only for TenneT, but also for our contractors and suppliers. Nevertheless, together we succeeded in achieving this performance. We can be proud of that," said Marco Kuijpers, TenneT's Director Offshore Projects.
Hollandse Kust (zuid)
The grid connection for Hollandse Kust (zuid) is located 22 kilometres off the coast of the Dutch province of South Holland. It consists of two transformer platforms at sea, each with two 220kV alternating current cables. The sustainably generated electricity is transported to land via these cables. TenneT has built a new onshore transformer station there and is expanding the high-voltage 'Maasvlakte 380kV' substation. From this high-voltage substation, offshore wind energy will be fed into TenneT's Randstad 380kV South ring. The wind energy goes to the electricity consumers in the country via the national high-voltage grid.