TenneT has now awarded the contract for the construction of the SuedLink converter stations in Wilster (Schleswig-Holstein) and Bergrheinfeld (Bavaria) to Hitachi Energy, which will plan and manufacture the systems with their experts in the state-of-the-art production facilities in Germany and Sweden. The order volume is several hundred million euros. All four converter stations required for the SuedLink, which consists of two pipeline projects with a capacity of two gigawatts each, have now been commissioned.

Tim Meyerjürgens, COO of TenneT, said: “SuedLink is the largest grid expansion project in Germany and thus a central component of the energy transition. The converter stations are essential so that SuedLink can primarily transmit wind power from northern Germany to southern Germany from 2028. With Hitachi Energy, we have commissioned a competent service provider with experience in the construction of converter plants.”

Niklas Persson, Managing Director of Hitachi Energy’s Grid Integration business, said: “We are proud to play a crucial role in this very important investment in Germany’s transition to renewable energy and carbon neutrality. Our HVDC solution is the enabling technology for large-scale transmission of renewable energy, both onshore and offshore.”

The high-voltage direct current technology used in SuedLink allows electricity to be transported more efficiently over long distances by better controlling load flows and keeping transmission losses low. To feed electricity into or out of the existing AC grid, converters are required that convert direct current into alternating current – or vice versa, depending on the desired flow direction of the current. With lower losses compared to AC transmission, DC technology enables long-distance transport and the integration of North German wind and South German solar power into the German transmission grid.

The converter locations in Wilster and Bergrheinfeld are next to the grid connection points stipulated by law. Both areas are already owned by TenneT, meaning no additional third-party areas have to be used. The first preparatory construction measures have already begun in Wilster. Due to the immediate proximity to the Wilster/West substation, there is no need for an overhead line connection there. In Bergrheinfeld, the connection to the existing Bergrheinfeld/West substation is established with a short overhead line. TenneT and Hitachi Energy will plan these converters in more detail in the coming months.


With a length of around 700 kilometres and an investment of ten billion euros, SuedLink is Germany’s largest infrastructure project for the energy transition. All project sections are in the planning approval process, in which the pipeline’s final route will be determined.

SuedLink consists of two DC transmission lines (Projects 3 and 4 of the Federal Requirements Plan Act), which are planned, built and operated in parallel by TenneT and TransnetBW. The converters in Wilster and Bergrheinfeld form the start and end points of project 4.

The converters for project 3 are located in Brunsbüttel (Schleswig-Holstein) and Großgartach (Leingarten) in Baden-Württemberg. TenneT and TransnetBW had already awarded the contract to build the two converters for Project 3 to Siemens last year.

At SuedLink, TenneT is responsible for the northern section of the route and the converters in Schleswig-Holstein and Bavaria. The southern section of the route and the converter in Baden-Württemberg fall within the area of ​​responsibility of TransnetBW.

State-of-the-art converter technology

The converters are rigid bipoles with a nominal active power of two gigawatts at a nominal DC voltage of ±525 kilovolts (kV). The most modern modular multilevel converter technology (MMC) is used. Thanks to VSC technology, the converters can flexibly and quickly adapt the active and reactive power to the respective grid conditions. They thus make an important contribution to grid stability.

Source: https://www.tennet.eu/
Image source: Courtesy of TenneT

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