innogy SE has taken the final investment decision (FID) for the construction of the 342 megawatt (MW) wind farm, which is located 35 kilometres north of the island of Heligoland. In preparation for construction, contracts for all major components have been signed. The contract value for wind turbines and foundations, the offshore transformer substation and the cabling for the wind farm is in the region of 500 million euros.

Christoph Radke, COO Renewables at innogy SE, explains:
“Offshore wind is an important pillar to reach Germany’s climate protection goals by supplying green electricity from a reliable source. I am delighted to announce that we have paved the way for the construction of our Kaskasi offshore wind project, which will become our third offshore wind farm off the German coast. Our investment in this project underlines our ambitions to further grow in offshore wind in Europe and around the globe.“

Sven Utermöhlen, Senior Vice President Renewables Operations Offshore at innogy SE, adds:
“Following our success in the German offshore auction in 2018, we have now taken the next important step in realising Kaskasi offshore wind farm. With Siemens Gamesa, Bladt Industries and Seaway 7 we have brought extremely experienced contractors and suppliers on board for all key components and their installation, which is expected to start next year.”

Wind turbines and foundations

innogy has signed a contract with Siemens Gamesa Renewable Energy S.A. for the supply of 38 SG 8.0-167 DD Flex offshore wind turbines. Each turbine will have a capacity of close to 9 MW, a rotor diameter of 167 metres, and a total height of 191 metres. The wind turbines as well as the substation will be installed on monopile foundations built by Bladt Industries A/S. Seaway 7 will commence installation of the foundations using a new installation method in third quarter of 2021 in moderate water depths of 18 to 25 metres. The so called “vibro pile driving” is an efficient alternative to the conventional method of hammering monopiles into the seabed. A research project led by innogy has shown that this improved installation method could deliver reduced installation times and noise emissions during construction. Kaskasi will be the first wind farm in the world using the vibro driving technique to install all monopile foundations to target penetration. In preparation for the offshore construction work, extensive seismic analyses has already been carried out.

Substation and wind farm cabling

innogy has contracted Bladt Industries A/S to construct, deliver and commission the offshore transformer substation. The offshore substation is the nerve centre of the wind farm: the electricity produced by the individual wind turbines is bundled and transformed to transmission-level voltage. From the substation the grid operator transports the energy via the existing HelWin2 converter platform further to coast. The wind turbines will be connected with the Kaskasi substation via 33kV aluminium subsea cables with different cross sections. Installation of approximately 50 kilometres of cable will be carried out by Seaway 7. The cables will be manufactured by the Dutch company Twentsche Kabel Fabriek (TKF).

Grid connection secured

It is expected that the wind farm will start operations in summer 2022, the final date will be set in coordination with the offshore grid operator TenneT. Kaskasi offshore wind farm is to be connected to the same grid connection cluster as innogy's nearby Nordsee Ost wind farm. The HelWin2 converter platform required for connection to the grid has already been operational for several years. Synergies with Nordsee Ost wind farm will be utilised with regard to operations and maintenance work: For example the Kaskasi wind farm will be operated from the existing innogy service and operations station on Heligoland. Once all wind turbines are operational, Kaskasi offshore wind farm will supply the equivalent of more than 400,000 with green electricity.

KeyFacts Energy: Renewable Energy news