Kriegers Flak

Location and Overview

The Kriegers Flak offshore wind farm is situated in the southern Baltic Sea, located in the waters between Denmark's Møn region, Southern Sweden, and Northern Germany. This area is favored due to its favorable wind conditions and water depths ranging from 16 to 25 meters.

Capacity and Layout

The wind farm has a total capacity of 604 MW, divided into two parts:

• Kriegers Flak A (KFA): Located in the western part, it has a capacity of approximately 200 MW, covering an area of 69 km².
• Kriegers Flak B (KFB): Located in the eastern part, it has a capacity of approximately 400 MW, covering an area of 110 km².

Turbines and Foundations

The wind farm features 72 SG 8.0-167 DD turbines supplied by Siemens Gamesa. Each turbine has a total height of 188 meters and is installed on foundations that include steel monopiles with concrete gravity bases, jacket-type foundations, and suction buckets. The foundations weigh up to 800 tons.

Electrical Infrastructure

The electricity generated by the turbines is transmitted to two 220kV offshore substations through inter-array cables with a total length of 170 km, laid underwater. The high-voltage stations serve the wind farm and act as interconnectors between the Danish and German electricity networks. ABB was involved in installing an AC cable system and providing an HVDC converter station. LS Cable and System delivered the 220kV cables to connect the turbines to the Bjæverskov and Ishøj substations, while Nexans provided 400kV cables to reinforce the power grid between the Ishøj and Hovegaard substations.

Combined Grid Solution

The Kriegers Flak wind farm is part of the Combined Grid Solution project, which interconnects the wind farm with the 288 MW Baltic II wind farm in Germany. This connection allows for the sharing of fossil-free energy between Denmark and Germany, enhancing the reliability and efficiency of the power grids in both countries. The transmission capacity of this interconnector is 400 MW.

Construction and Operation

• First Foundation: Installed in May 2020.
• First Turbine: Installed in early 2021.
• Operational Start: The wind farm began operations in June 2021.
• Service Facility: The wind farm is serviced from Vattenfall’s service facility at the Port of Klintholm on Møn, approximately 100 kilometers south of Copenhagen. During the installation phase, turbines were preassembled and shipped out of the Port of Rønne on the island of Bornholm.

Environmental and Technical Aspects

• Environmental Impact: NIRAS prepared the environmental impact assessment report and conducted environmental studies for the offshore wind farm.
• Geological and Met-Ocean Studies: Comprehensive site-specific met-ocean and geological studies were conducted to assess the seabed and sub-seabed conditions, including UXO risk assessments.

Economic and Energy Impact

• Investment: The project was developed with an estimated investment of kr7.6bn ($1.2bn).
• Energy Production: The wind farm caters to the power requirements of approximately 600,000 households per year.
• Price: The project was awarded to Vattenfall at a fixed price of €49.90 per MWh, which was the lowest price for offshore wind at the time of the tender in 2016.

Interconnection and Grid Integration

The wind farm is connected to both the Danish and German power grids, allowing for the transmission of power between the two countries. This interconnection enhances the overall reliability and efficiency of the power grids and allows for the sharing of renewable energy between Denmark and Germany.

Future Developments and Related Projects

While the Danish Kriegers Flak wind farm is operational, the Swedish Kriegers Flak project, which was planned to be located about 30 km south of Trelleborg, has been paused due to unviable investment prerequisites in Sweden. This Swedish project was estimated to generate 2.7 TWh of fossil-free electricity per year but is currently on hold until further notice.