The substation at the Hollandse Kust Zuid (HKZ) offshore platform is expected to begin operations by the end of next year


The Alpha jacket weighing 3,200 tons was transported by heavy lifting crane vessel, Sleipnir. (Credit: Unsplash/Nicholas Doherty)

TenneT, a Dutch transmission systems operator, has announced the installation of the first jacket at its Hollandse Kust Zuid (HKZ) offshore platform, off the coast of the Netherlands.

A few days ago, the Alpha jacket weighing 3,200 tons was transported by heavy lifting crane vessel, Sleipnir.

The 29m long, 20m wide and 46m high jacket is the foundation for the first of the two transformer substations for the 1.5GW HKZ offshore wind farm.

The two 220kV sea cables that will transmit the power generated from the wind farm ashore are expected to connected to the substation in the coming months.

The topside of the substation could installed onto the jacket next year and the by the end of that year, the offshore platform will start operations.

Vattenfall will connect its 1.5GW HKZ wind farms to the substation platforms

The Alpha and Beta substation platforms will be used by Vattenfall to connect the HKZ wind farms to the grid.

As per TenneT’s estimates, it will have built 3.5GW in offshore grid connections by the end of 2023, for the offshore wind projects.

The first 1.4GW was realised through the installation of Borssele Alpha and Beta. With the present HKZ Alpha and Beta, followed Hollandse Kust (Noord), the company will have five identical 700MW transformer platforms for the wind farms.

All the five substations use the same type of 220kV cable connections and are located close to the wind farms.

TenneT chief operating officer Tim Meyerjürgens said: “Such standardisation enables TenneT to complete these projects more efficiently, more quickly and more economically.”

In August, TenneT has selected the consortium of Siemens and Dragados Offshore to build converter stations for the BorWin5 offshore grid connection project.

NKT has also been selected to supply the DC underground and submarine cables for the project.

When completed, BorWin5 will be the 15th offshore grid connection system to be realised by TenneT in the German North Sea.