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Testing foundations of HKZ: the final rehearsal

nov. 3, 2020

Preparatory work for the construction of the Hollandse Kust Zuid wind farm is in full swing. Earlier this year, a test foundation was installed on the Maasvlakte at the terminal of Sif.

Things can get pretty rough on the North Sea; strong gusts of wind, treacherous currents and high waves. The foundations of the 140 wind turbines of the Hollandse Kust Zuid wind farm must of course be able to withstand all weather conditions. In addition, factors such as water depth and the seabed soil conditions also play a role in the design of wind turbines. During the test phase, the installation of the various wind farm components at sea was simulated.

Foundation without transition piece

In the summer of 2021, Vattenfall will start installing the 140 monopile foundations with a new design; without transition piece. All parts that are normally attached on a transition piece, the work platforms and ladder, will be placed directly to the monopile. Without a transition piece, Vattenfall hopes to be able to construct the wind farm faster and at reduced costs.


In May 2020, Vattenfall started the test of the foundations at Maasvlakte 2 - also known as a mock-up trial. Each supplier tested the offshore installation activities on the test foundation. In total, the test period lasted about two months.

At the end of October 2020, all feedback points from the mock-up trial will be definitively submitted and implemented in the design. The second and final mock-up trial is scheduled for March 2021.