Hollandse Kust Zuid Holland III and IV

Location

The Hollandse Kust Zuid wind farm is situated in the North Sea, approximately 18-36 kilometers off the Dutch coast, between the towns of Scheveningen and Zandvoort. Specifically, the HKZ III and IV sites are located west of the Netherlands, offshore the provinces of Zuid-Holland (South Holland) and Noord-Holland (North Holland).

Ownership

The wind farm is jointly owned by Vattenfall, a Swedish energy company, BASF, a chemicals company, and Allianz, an insurance company. The ownership stakes are approximately 25.3% for Vattenfall, 49.5% for BASF, and 25.2% for Allianz, although slight variations in percentages are noted in different sources.

Capacity and Turbines

• The entire Hollandse Kust Zuid wind farm has an installed capacity of 1.5 GW, with HKZ III and IV contributing 760 MW to this total.
• The wind farm features 139 turbines in total, with HKZ III and IV specifically consisting of 70 turbines.
• Each turbine is a Siemens Gamesa SG 11.0-200 model, with a capacity of 11 MW, a rotor diameter of 200 meters, and blade lengths of 97 meters. The tip height of each turbine is 225 meters above sea level.

Infrastructure

• The turbines are mounted on fixed monopile foundations, which weigh between 735 and 955 tons and are installed at water depths ranging from 17 to 28 meters.
• The wind farm includes 315 km of 66kV inter-array grid cables and two offshore transformer platforms, HKZ Alpha and HKZ Beta, each with AC connections of 700MW. The electricity is stepped up to 220kV at these platforms and transported through export cables to the onshore 380kV Maasvlakte high-voltage substation.

Construction and Operation

• The construction of the wind farm began in July 2021, with the final investment decision taken by Vattenfall in June 2020.
• The wind farm was officially inaugurated in September 2023 and is expected to be fully operational by 2024. Operations and maintenance will be controlled from Vattenfall’s new service facility in the Port of IJmuiden.

Environmental and Biodiversity Measures

• Innovative techniques were used during construction to minimize environmental impact, such as a double bubble screen to reduce underwater noise during pile driving, protecting harbour porpoises.
• The turbine foundations include enlarged water replenishment holes to provide shelter for marine life, and artificial rock reefs were added to scour protection sites to attract fish, crabs, and crustaceans.

Grid Connection

• The wind farm is connected to the Dutch grid via two offshore substations operated by TenneT, the Dutch transmission system operator. These grid connections are publicly funded, ensuring standardization and cost savings.

Economic and Social Impact

• The project is a significant infrastructure investment, creating economic activity and employment opportunities in the region.
• The wind farm will supply enough clean energy to power approximately 1.5 million households in the Netherlands, contributing substantially to the country's renewable energy targets.

Contractors and Suppliers

• Key contractors include Siemens Gamesa for turbine manufacturing, Sif Group for foundation manufacturing, Subsea 7 and Seaway 7 for foundation and cable installation, and Swire Blue Ocean for turbine installation.

Power Purchase Agreement

• A portion of the power generated from the project will be sold to Air Liquide under a power purchase agreement for a period of 15 years starting from 2025, with an offtake capacity of 115 MW.

The Hollandse Kust Zuid wind farm, including the HKZ III and IV segments, is a landmark project in offshore wind energy, marking the world's largest subsidy-free offshore wind farm and a significant step towards achieving fossil-free living and reducing carbon footprints.