Kaskasi

Location and Site Details

The Kaskasi Offshore Wind Farm is located approximately 35 kilometers north of the island of Heligoland in the German sector of the North Sea. It is situated near other RWE offshore wind farms, including Amrumbank West and Nordsee Ost.

Ownership and Development

The Kaskasi Offshore Wind Farm is owned and developed by RWE, although the project was initially developed by innogy, a wholly-owned subsidiary of the German energy company E.ON, before being taken over by RWE.

Capacity and Turbines

The wind farm consists of 38 Siemens Gamesa wind turbines, each with a rated capacity of up to 9 MW. The turbines are of the SG 8.0-167 DD model, featuring 167-meter diameter rotors, 81.5-meter long fiberglass-reinforced epoxy blades, and a hub height of 107.5 meters. Each turbine incorporates Siemens Gamesa Power Boost technology and operates at 690V voltage and 50Hz frequency.

Installed Capacity and Electricity Generation

The Kaskasi wind farm has an installed capacity of 342 megawatts (MW). Since its commissioning, it is capable of supplying the equivalent of approximately 400,000 households with green electricity annually.

Construction and Timeline

• The approval procedure for the wind farm began in spring 2019.
• The German Federal Maritime and Hydrographic Agency (Bundesamt für Seeschifffahrt und Hydrographie) greenlighted the construction at the end of 2020.
• The final investment decision (FID) was made in April 2020.
• Construction works started in the third quarter of 2021.
• The total offshore construction time was nine months.
• The turbines were successively commissioned over four months, with all turbines feeding green electricity into the grid by the end of 2022.
• The wind farm officially commenced regular operation on March 23, 2023.

Investment and Contractors

The investment costs for the Kaskasi wind farm amounted to approximately 800 million euros. Several key contractors were involved:

• Siemens Gamesa Renewable Energy supplied the 38 wind turbines.
• Bladt Industries provided the monopile foundations and transition pieces, as well as the engineering, production, construction, and installation (EPCI) of the offshore transformer substation.
• Seaway 7 handled the transport and installation of the wind turbine generator monopile foundations, the offshore substation foundation, and the inner array grid cables.
• Twentsche Kabel Fabriek (TKF) supplied the 52 kilometers of 33kV aluminum core inner array cables.
• CAPE Holland provided the Vibro Lifting Tool (VLT) for the installation of monopile foundations using vibro piling technology, a method that ensures faster and quieter installation compared to conventional hammering.

Foundation and Power Transmission

Each turbine is mounted on a 64-meter high monopile foundation, installed using vibro piling technology. The electricity produced is gathered and transmitted through 52 kilometers of 33kV inner array grid cables to an offshore transformer substation. The electricity is then transported onshore via the existing HelWin2 converter platform, which is owned and operated by TenneT.

Operational Management

The Kaskasi wind farm, along with the Amrumbank West and Nordsee Ost wind farms, is operated and maintained from RWE's service station on Heligoland. Around 100 service technicians, engineers, and control room staff ensure the smooth operation of these wind farms.

Innovations and Environmental Impact

The Kaskasi wind farm features the world’s first recyclable rotor blades tested under real-life conditions. Three turbines are equipped with these recyclable blades, which use a new resin with a special chemical structure that allows for the separation of materials for future reuse.

Role in Energy Transition

The Kaskasi wind farm is a significant project in Germany's energy transition. It marks an important milestone in the expansion of offshore wind power in Germany. German Federal Minister for Economic Affairs and Climate Action, Robert Habeck, emphasized the importance of offshore wind in producing more electricity for more hours per year compared to onshore turbines. Germany has increased its expansion targets for offshore wind energy to at least 30 gigawatts by 2030.