Hohe See

Hohe See Offshore Wind Farm Profile

Location and Geography

• The Hohe See offshore wind farm is located in the German North Sea, approximately 98 km off the German coast and 90 km north of Borkum island, within the German exclusive economic zone.
• The wind farm is situated around 100 km northwest of Helgoland.

Project Details

• The Hohe See wind farm has a total capacity of 497 MW.
• It is part of a larger project that includes the adjacent Albatros wind farm, together forming the largest offshore wind project in Germany with a combined capacity of 609 MW.

Ownership and Partners

• The project is owned by EnBW Energie Baden-Württemberg AG (50.1%) and Enbridge Inc. (49.9%).

Turbines and Technology

• The wind farm features 71 Siemens SWT-7.0-154 turbines, each rated at 7 MW. These turbines have a rotor diameter of 154 meters, a hub height of 105 meters, and a total height to blade tip of 182 meters.
• Each turbine tower, including the nacelle and rotor blades, weighs approximately 755 tons. The rotors cover an area of 18,630 square meters.

Foundations and Infrastructure

• The turbines are anchored into the seabed using monopile foundations. Each monopile is approximately 70 meters long and weighs 1,500 tons. The transition pieces are each about 30 meters long.
• The substation features a semi-open topside steel structure resting on a jacket foundation, weighing around 3,100 tons.

Grid Connection

• The wind farm is connected to the German grid through the BorWin3 platform, a high-voltage direct current (HVDC) grid connection system, and the BorWin Gamma converter platform.

Construction and Commissioning

• The design phase began in February 2016, and the construction commenced in 2018. The first offshore wind turbine installation was completed in April 2019, and the construction of the wind farm was completed in August 2019.
• The wind farm began operations in October 2019 and was fully connected to the grid in January 2020.

Contractors and Suppliers

• Siemens Gamesa Renewable Energy supplied the turbines and is responsible for the operation and maintenance for a period of five years after commissioning.
• Deme Group subsidiary GeoSea designed, manufactured, and installed the foundations and transition pieces. GeoSea subcontracted Sif Holding to produce the monopile foundations and collaborated with Smulders for the transition pieces.
• Boskalis’ subsidiary VBMS was responsible for the supply and installation of the inter-array cables.
• ZTT constructed the 155kV HVAC-grid connection and supplied shunt reactors, GIS terminal, and land conversion joints.

Environmental Impact and Energy Production

• The Hohe See wind farm generates approximately 2 billion kilowatt-hours (kWh) of renewable electricity per year, which is sufficient to power around 560,000 homes.
• The project offsets about 1.5 million tons of carbon dioxide (CO₂) emissions annually.

Logistical and Operational Aspects

• Over 600 employees were involved in the construction process, with around 50 ships participating in the construction work.
• The components for the wind farm were built on land and transported from countries including Denmark, Germany, Holland, and Belgium to the construction site in the North Sea.