Arkona

Location and Overview

The Arkona offshore wind farm is situated approximately 35 kilometers northeast of the island of Rügen in the German part of the Baltic Sea.

Capacity and Output

The wind farm has a total capacity of 385 megawatts (MW) and is equipped with 60 Siemens SWT-6.0-154 direct-drive wind turbines, each rated at approximately 6 MW. This setup enables the wind farm to supply renewable energy to around 400,000 German households and offset up to 1.2 million tons of CO2 emissions annually.

Turbine Specifications

• Each turbine has a rotor diameter of 154 meters and 75-meter-long blades, providing a swept area of 18,600 square meters.
• The turbines operate within a speed range of 5 to 11 revolutions per minute (rpm) and are mounted on monopile foundations installed at depths ranging from 23 to 37 meters.

Project Development and Construction

• The project was developed by a 50/50 joint venture between the German utility E.ON (now part of RWE) and the Norwegian energy company Equinor (formerly Statoil).
• The final investment decision was made in April 2016, and construction began with the first monopile installation in September 2017.
• The wind farm was fully commissioned in April 2019, with the first electricity fed into the German grid in September 2018.

Infrastructure and Installation

• The wind turbines were pre-assembled at the wharf of the Port of Sassnitz in Mecklenburg-Vorpommern, which served as the logistics base for the project.
• A2SEA was responsible for installing the turbines using its offshore installation vessel Sea Challenger. Van Oord supplied and installed the monopile foundations and transition pieces.
• The offshore substation, weighing 5,000 tons, was manufactured by STX France (now Chantiers de l’Atlantique) and installed by Seaway Heavy Lifting (SHL). The substation is jointly operated by OWP Arkona and 50Hertz.

Grid Connection

• The electricity generated is transmitted to the national grid via the 93km-long Ostwind 1 cable system, which connects to 50Hertz’s onshore substation at Lubmin in Mecklenburg-Vorpommern. This system also provides grid connections to the Wikinger wind farm.

Contractors and Services

• Siemens Gamesa was contracted to supply, install, and commission the turbines, including a two-year service agreement.
• VBMS was responsible for the inter-array cabling, while Nexans provided 76 kilometers of energy cables for the project.
• DNV performed the project certification, including design assessment, manufacturing, transport, installation, and commissioning surveillance.
• Other contractors involved included Fugro Consult for geotechnical investigations, DHI Group for hydrography and metocean data, and Strabag Offshore for wind measuring platforms.

Economic and Environmental Impact

• The project required an investment of approximately €1.2 billion (or $1.4 billion).
• The wind farm created up to 400 construction jobs and 50 direct permanent jobs, along with 100 indirect jobs.
• It is estimated to generate up to 1.5 terawatt-hours (TWh) of clean electricity per year, significantly reducing CO2 emissions.

Operational Management

• E.ON led the construction and is responsible for the operation of the wind farm. RWE, following the integration of E.ON's renewable energy assets, now operates the offshore wind farm on behalf of the partners.
• The electricity produced is purchased by Engie under a four-year power purchase agreement (PPA) signed in September 2018.