EnBW Baltic 2 wind farm

Our site managers and logistics specialists can expect challenging tasks, such as estimating the working speeds, calculating the transport routes – and coordinating everything with the weather conditions.

One single ship for the wind turbines, up to two ships for the foundation structures and up to three ships for connecting the cables travel from different ports and arrive at the construction site at different times. The site is further secured by a sea traffic management vessel.

The sea is a capricious project partner: It must not be too cold, otherwise the special cement used to join the foundation components will not set.

The transformer platform needs calm seas to reach its destination and set itself up. The wind turbines can only be installed at wind speeds of up to force 4–5.

For each construction phase, all components not only have to be transported to and installed at the site, which lies 32 km off the German coast, but the crews also need to be regularly replaced.

Even though it only takes around two hours for the crew transfer ships to sail to the construction site from our base port in Sassnitz, a heavy installation platform can take up to 12 hours to get there. As such, it is essential to think of everything – because every delay can cost a six-figure sum each day.

Measuring 40 x 40 meters wide and 14 meters high and weighing 4,400 tons, the transformer platform floats on its own. Besides saving transport costs, the installation of the platform is also less complex: It brings the upper section of its foundations with it in an inwardly retracted state and can therefore base itself on the preinstalled lower section.

Firstly, tugboats tow the transformer platform from the shipyard to the construction site. Once in position, it lowers its jacket foundation structure and lifts itself up about one meter above sea level. Only the substructure on which the jacket structure sits must firstly be anchored to the seabed using foundation piles.

The electricity from the 80 wind turbines flows into the substation and is transformed from a voltage of 33 kV to 150 kV. A low voltage requires a very thick cable to transport electricity in order to prevent transmission losses.

To avoid having to lay such a cable underwater for several kilometers, the electricity is transformed as close as possible to the generation source, which is why the transformer platform is installed at the wind farm on the high seas rather than on land.

The wind farm’s internal power grid is around 85 kilometers long. The cables are transported to the construction site directly from Norway.

Besides transporting the electricity, the 11.9- and 14-centimeter-thick submarine cables also transmit information and data between the turbines and the control room in Barhöft via highly sensitive optical fibers that are integrated into the cables.

The so-called export cable transports the electricity from the substation via EnBW Baltic 1 to the nearest substation on land. Here, at Bentwisch substation, the voltage is once again transformed from 150 kV to 380 kV and fed into the German grid by 50Hertz Transmission GmbH.