Germany currently operates two offshore wind farms in the Baltic Sea, Baltic 1 (48 MW) and Baltic 2 (288 MW). At present, Denmark is preparing the construction of the offshore wind farm Kriegers Flak (600 MW). The Kriegers Flak (Denmark) and Baltic 2 (Germany) wind farms are less than 30 kilometres apart. The interconnector should be established by connecting both wind farms by means of two submarine cables.
The frequencies of the Danish and German transmission systems use a slightly different phase. That is why they need to be matched at the interface. This should be enabled by means of two serial voltage source converters (VSC). A converter transforms the alternating current (AC) from the Nordic interconnected system to direct current (DC). Another converter transforms this direct current back to alternating current - only now adapted to the synchronous area of continental Europe.
This so-called back-to-back converter should be installed in Bentwisch, near Rostock. The construction of the double converter on land is more favourable and allows easier maintenance than the construction and opration of the installation on an offshore platform. This was provided for in the original concept.
Due to the different voltage levels of the Danish and German offshore wind farms (150 to 220 kilovolt), a transformer is also required. However, this should be installed on the Danish offshore platforms.