Hollandse Kust Zuid Wind Farm Zone (HKZWFZ) is a 1.5GW offshore wind farm complex planned to be developed 22km away from the Dutch North Sea coast, Netherlands.

The offshore wind power zone will comprise four wind farm sites of more than 350MW installed capacity each.

Vattenfall won the tender for the Hollandse Kust Zuid wind farm sites (HKZWFS) I and II in the HKZWFZ tender round concluded in December 2017.

Vattenfall received permits for the construction and operation of the 750MW Hollandse Kust Zuid I and II offshore wind farms from the Dutch Minister of Economic Affairs and Climate Policy in September 2018.

Preparatory works including site surveys and detailed design are currently underway for the project. Vattenfall plans to start construction on the £1.3bn ($1.6bn) offshore wind project in 2022 and turn it operational by 2023.

Vattenfall also won the tender for the 750MW Hollandse Kust Zuid III and IV wind farm sites in July 2019. Permit for the construction and operation of the same is, however, awaited.

Hollandse Kust Zuid I-IV wind farms will be one of the world’s first non-subsidized wind projects and are expected to generate enough clean electricity to power up to three million Dutch households a year.

Hollandse Kust Zuid wind farm zone location

Hollandse Kust Zuid wind farm zone will encompass a 235.8km² in the coastal waters of Zuid-Holland (South Holland) province, off the west coast of Netherlands.

 Hollandse Kust Zuid I & II wind farms make-up

Covering 67.2km² and 47.7km² respectively, the HKZWFS I and II wind farms will feature a total of 76 SG 10.0-193 direct drive turbines from Siemens Gamesa.

The SG 10.0-193 DD turbine is one of the most powerful commercially available wind turbines in the world and is expected to increase offshore wind power generation efficiency by 30%.

With a rotor diameter of 193m and blade length of 94m, each pitch-regulated variable-speed wind turbine has a swept area of 29,300m² and rated power of 10MW.

The operation and maintenance of the wind farm will be carried out from a new service centre to be developed at the IJmond harbor area near the Port of Ijmuiden. The service centre will be an energy-efficient building with solar panels installed on its roof.

The wind farm is expected to be employed with 40 full-time professionals during its operation phase. Vattenfall plans to utilise hydrogen-powered boats for the offshore transport of maintenance staff.

Power transmission

The power generated by the turbines at Hollandse Kust Zuid wind farm zone will be gathered and transmitted through 66kV cables to two offshore substations namely Hollandse Kust (zuid) Alpha and Hollandse Kust (zuid) Beta.

Power from each offshore substation will be transmitted onshore through two 220kV cables connecting the high-voltage Maasvlakte substation on the mainland, before connecting further with the Randstad 380kV South Ring transmission system.

TenneT, the offshore grid operator in the Netherlands, will be responsible for the development and operation of the transmission infrastructure of the Hollandse Kust Zuid wind farm zone.

TenneT and Vattenfall signed agreements for the offshore grid connection of the Hollandse Kust Zuid I and II projects via the Hollandse Kust Zuid Alpha offshore platform in January 2019.

Contractors involved

Vattenfall announced Siemens Gamesa as the supplier of wind turbines for the HKZWFS I and II wind farms in April 2019.

Windcat Workboats has been contracted for the supply of hydrogen-powered crew transfer vessels (CTVs) for the maintenance of the wind farm.

A consortium of Van Oord and Hellenic Cables was selected by TenneT to supply and install cables for the Hollandse Kust Alpha and Beta transmission projects in September 2018.

LMR Drilling was chosen to perform horizontal directional drilling for the transmission projects.

Seaway 7, the renewables and heavy lifting unit of Subsea 7, was contracted to transport and install 76 monopile foundations as well as for laying the inter-array cables for the HKZWFS I and II wind farms in April 2019.

Petrofac is responsible for the engineering, procurement, construction, and installation of Hollandse Kust (zuid) Alpha and Beta HVAC offshore substations, under two separate contracts awarded in July 2018 and June 2019, respectively.

Heerema Marine Contractors was subcontracted by Petrofac for the transport and installation of the Hollandse Kust (zuid) Alpha platform in May 2019.