TenneT and 50Hertz team up for integration of 4GW German offshore wind

TenneT and 50Hertz have teamed up on the grid connection of 4GW of German North Sea offshore wind power to shore and its subsequent integration into the power grid onshore.

The two transmission system operators (TSOs) have signed a cooperation to build a multi-terminal hub on land in the area of Heide in Germany’s northernmost state of Schleswig-Holstein and an extra-high voltage direct current link (HVDC) to the state of Mecklenburg-Vorpommern to the east.

"If Germany is to become climate-neutral by 2045, there must be even more focus on cooperation in the future,” 50Hertz chief executive Stefan Kapferer said.

“50Hertz and TenneT are therefore working together and joining forces to tackle this challenging project in order to transport as much electricity generated at sea as quickly as possible to where it will be urgently needed in the future."

Dutch-German TSO TenneT so far has been responsible for offshore wind grid links from the North Sea, and 50Hertz from the Baltic Sea due to the respective geographical areas within the country they serve, but Germany’s plans for an accelerated expansion of wind at sea make a closer cooperation between the TSOs necessary.

TenneT chief operating officer Tim Meyerjürgens said the two TSOs with the joint implementation of the onshore hub are laying the foundation for a higher utilisation of onshore DC lines and increase the level of security of supply.

“In addition, the concept enables to accelerate the expansion of offshore wind energy, as envisaged by the new German government,” Meyerjürgens said.

“With the implementation of the onshore hub and the three grid expansion projects linked to it, it will be possible to connect four gigawatts of offshore wind energy from the North Sea in the area of Heide as early as 2032.

“This means that one part of the project will be completed three years and another even five years earlier than originally planned in the grid development plan."

The two offshore grid links for the area of Heide confirmed in 2035 grid development plan will be implemented separately as NOR-12-2 system to be connected to the multi-terminal-hub by 50Hertz and the NOR-X-3 system by TenneT.

The two TSOs plan to build an underground DC cable of about 200 kilometres between Heide and Klein Roghan near Schwerin in Mecklenburg-Vorpommern that will transmit power at 525 kilovolt.

The multi-terminal hub solution is an innovation as so far DC connections at sea and on land have ben realised only as point-to-point connections, while in the multi-terminal hub, several of those grid links converge.