Nezzy 2 - Floating wind turbine successfully tested in the Baltic Sea

A model of the floating wind turbine Nezzy2 was successfully tested during a storm surge on the Baltic Sea. At the end of 2021, Nezzy2 is to be tested in its original size for the first time in China.

Rendsburg. According to data from the Federal Ministry for Economic Affairs and Energy (BMWi), wind turbines with an output of 52.5 gigawatts on land and 6.4 gigawatts at sea were installed in Germany in 2018. In order to be able to meet the federal government's climate targets, the total output of the offshore wind turbines is to be expanded to 15 gigawatts by 2030.

Although wind turbines save CO2 emissions, this planned expansion is criticized by some environmental and animal welfare organizations because offshore wind turbines have so far required solid foundations that are anchored in the seabed. This leads to a high level of noise pollution in the water, which is said to be harmful to marine mammals and fish. A wind turbine recently presented by the Dutch company Fistuca is significantly quieter, but can only be used up to a water depth of 50 meters.

Floating wind turbines

The Rendsburg company Aerodyn Engineering has now tried out a solution to this problem in cooperation with the energy supplier EnBW in the Baltic Sea. The newly developed floating wind turbine Nezzy2 consists of a platform that is attached to the sea floor with a kind of anchor without a foundation. On the platform there are wind turbines with three rotor blades each, which are connected to each other and to the platform by guy ropes. In contrast to the Fistuca wind turbine, even deep water is no problem for Nezzy2.

Survived storm surge without damage

So far, Nezzy2 has only existed as a model about meters high. A first test took place in summer on a quarry pond near Bremerhaven. The wind turbine was also recently tested in the Greifswalder Bodden in the Baltic Sea under autumn weather conditions. 180 sensors collected information about the behavior of the system at different wave heights and directions as well as wind directions and speeds.

In mid-October, the facility was also hit by a storm surge that Nezzy2 was able to withstand without damage. According to the developers, the wind and waves corresponded to a category four to five cyclone with waves up to 30 meters high, transferred to the size of the planned productive plant.

According to Aerodyn boss Siegfriedsen, the company was able to observe for one and a half days how Nezzy2 was stable in the water under extreme weather conditions.