Asso.subsea Ostwind 3

Asso.subsea to install export cable for Ostwind 3

Hellenic Cables has signed a contract with Asso.subsea for the transportation, installation, and protection of the 220 kV submarine export cable that will connect 50Hertz’s own transformer platform at the Windanker wind farm in the Baltic Sea to the national grid as part of the Ostwind 3 grid connection system.


The overall system will consist of one export cable for a total length of more than 100 kilometres.

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The export cable will be installed along a route characterized by numerous technical challenges, including shallow water areas, landfall pull-in through a 900-metre-long HDD conduit, boulder fields, numerous crossings, and soil conditions varying from very soft to hard soils.

For this work, the company will utilise its DP2 cable-laying vessel Atalanti, specialised in extremely shallow water working environments, and DP3 cable-laying vessel Ariadne for deep water cable installation and platform pull-in.

Additionally, the DP2 trenching support vessels Argo and Aethra will participate in the seabed preparation and post-lay burial operations.

The latest versions of the trenching machines from the AssoTrencher V for cable burial in very shallow waters, AssoTrencher IV as well as the AssoJet III families will be mobilised in order to provide the required protection of the cables along the entire submarine route.

Ostwind 3 is the grid connection project of the 300 MW Windanker offshore wind farm in the Baltic Sea, developed by Iberdrola.

The wind farm, for which Iberdrola exercised its step-in-right to the pre-developed site O-1.3 in November last year, will be built in the area Westlich Adlergrund, north of the operating wind farms Wikinger and Arkona which are connected to 50Hertz’s operational grid connection system, Ostwind 1.

Windanker is planned to be put into operation in 2026 and will be the first offshore project in the German Baltic Sea at market conditions, according to Iberdrola.

The wind farm is part of the company’s Baltic Hub, which includes the Windanker project, the operational Wikinger offshore wind farm, and the Baltic Eagle (currently under construction).

With an installed capacity of over 1.1 GW by 2026, the Baltic Hub is expected to supply over 1.1 million German households with electricity.