Grid connection – the important link to the mainland
The DanTysk wind farm's grid connection is key to enabling the green energy produced in the North Sea to be fed into the German power grid. The transmission system operator responsible for the North Sea region, Tennet, will be in charge of this task. The company has been on board with the DanTysk wind farm project since January 2011; once all of the decisive criteria were reviewed, such as full authorisation, construction planning and signed financing agreements, Tennet agreed to provide unrestricted grid connection.
Low-loss transport via a DC cable
The DanTysk wind farm will be connected to the mainland via the 'Sylwin 1' grid connection. This is a submarine cable connection which will link up the converter platform Sylwin alpha, located directly next to the wind farm, with the substation in the town of Büttel in Schleswig-Holstein. For this purpose, a 205-kilometre-long cable will be laid; 160 km will be submerged in the North Sea and 45 km will cover the distance on land leading to the Büttel converter station. It is here that the electricity will be fed into the German extra-high voltage grid.
Converters are systems that convert the AC energy generated by the wind turbines into DC electricity. They also work in the opposite direction; once transported via the submarine cable, energy can be converted back into AC electricity so it can be fed into the extra-high voltage grid. This step is required due to the fact that energy, under certain conditions, can be transported more efficiently over large distances with direct current technology. This high voltage direct current transfer – as the specialists call it – enables the low-loss transfer of energy both on land and offshore.