Update on the construction of Hollandse Kust Zuid and on the potential audibility of the construction activities

Since the last update in April, a lot of progress has been made on the construction of Hollandse Kust Zuid Wind Farm. More cables have been laid on the seabed, foundations are piled and turbines have been installed. In this article we will give you an update on the construction process and the potential audibility of some of the construction activities.  

Foundation installation 

After a winter break, the installation of the foundations by Seaway’s Strashnov restarted in April. 93 foundations are installed and 53 of the 140 foundations will be installed over the next period. The foundations that are currently being placed, are the once closer to the coast (19 km), within the sites Hollandse Kust 3&4. 

It has recently appeared that, for foundations closer to shore, certain weather conditions may lead to the piling part of the foundation installation being intermittently audible onshore. The piling is an essential part of the offshore construction of the wind farm and cannot be avoided but the progress of foundation piling in HKZ is now already more than 65% complete so future instances of audible noise onshore will be limited. 

Unfortunately, it cannot be determined with certainty when the noise from the construction of the wind farm will be audible on the coast. This depends for example on the location of the piling in relation to the coast, the wind speed, wind direction, wave height and ambient noise levels. It currently seems that the noise only carries to the coast under specific circumstances. Normally, only when the weather is very calm and there are no other noises, the pile driving might be audible at the coast. 

Although construction of the wind farm continues 24/7, there are only two to three monopiles per 48 hours installed. The period of installation when noise is produced for one monopile takes on average 2 hours. It is not possible to say exactly when the next foundations will be placed. This depends, among other things, on the weather, the progress of other related activities in the area and possible unforeseen matters that can occur in such a large project. The installation of the foundations is forecast to take until after the summer (September). 

The Installation of every monopile is followed by the installation of the external working platform on top of the monopile. This work is performed by Jumbo with its vessel the Fairplayer. 

Cable installation 

The second part of the construction process is the laying of the cables that will transport the power from the turbines to the substations. 74 of the 140 cables are now laid. On the crossings between existing cables on the seabed – for example data cables – and the cables of the wind farm, protection material has been installed to prevent damage to the cables. 

Turbine installation 

In April the first Siemens Gamesa 11 MW turbine was installed. Since then, Cadeler’s installation vessel Wind Osprey has been taken multiple offshore trips and Siemens Gamesa has been installing 36 turbines already on the foundations. On each trip, parts for four turbines are loaded on board: four towers, four turbine nacelles and twelve blades.

On 2 August the first turbine achieved successful delivery of the first sustainable energy to the Dutch grid. A huge milestone for the project. Read more about it here. The aim is to have all turbines installed by mid 2023. The coming months all activities will continue with Hollandse Kust Zuid Wind Farm steadily delivering more sustainable energy to the grid. The Hollandse Kust Zuid project is being built by Vattenfall and owned by Vattenfall, BASF and Allianz.

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Vattenfall generates and supplies electricity, heating, cooling and gas as well as offering customers a variety of sustainable solutions. Vattenfall want to achieve fossil-free energy generation within one generation. This Swedish energy company is investing heavily in wind energy to achieve this aim. We are working towards a sustainable world, for now and in the future.