Transmission system operators TenneT and TransnetBW are driving the SuedLink energy transition project further forward. In parallel with the ongoing approval procedures, both companies have opted for plastic-insulated 525 kV underground cables. Contracts to deliver and lay the underground cables have been awarded to NKT GmbH & Co. KG and Prysmian PowerLink S.r.I. The combined value of the contracts is approx. €2 billion.
“In the future, SuedLink will form the backbone of the energy transition in Germany. With the commissioning of the direct current ground cables, we are now moving from the planning stage to the realisation of this important power link,” says Tim Meyerjürgens, Managing Director of TenneT. About 2,500 km of cable will be needed to cover the planned four-gigawatt transmission capacity between Schleswig-Holstein, Bavaria and Baden-Württemberg.
Following pre-qualification tests involving a number of cable manufacturers, TenneT and TransnetBW opted to use plastic-insulated underground DC cables with a voltage level of 525 kV for SuedLink, since the high-tension cables can transmit more power. Another benefit: only half as many cables are required compared to a 320 kV solution. Lower transmission losses and less civil engineering work mean the SuedLink cables will not only offer financial benefits but also have minimal impact on the landscape. “We are very happy to be able to apply this innovative and environmentally benign technology for SuedLink,” comments Dr Werner Götz, Chair of the Executive Board of TransnetBW.
The technical suitability and operational safety of the 525 kV cables were first tested during a multi-year testing phase involving several cable manufacturers. The cables were repeatedly exposed to various stresses under realistic conditions, and the success of these pre-qualification tests showed that this technology is both reliable and safe.
The two cable manufacturers will be responsible for all aspects of the work, including design, manufacture, logistics and installation of the underground cables in the prepared channels and crossings, assembling the junction boxes and terminals, and the final high-voltage testing of the cable system. The cables are manufactured in accordance with the highest currently applicable quality and sustainability standards by NKT in Cologne and Karlskrona (Sweden), and by Prysmian in Gron and Montereau (France) and Pikkala (Finland).