Next-Gen Transmission Tech Under Development in Germany; Multiterminal Hubs to Enable Feeding Vast Amount of Offshore Wind Electricity Into Grid

July 17, 2024, by Adrijana Buljan

The four German transmission system operators (TSOs), 50Hertz, Amprion, TenneT, and TransnetBW, and transmission system suppliers Siemens Energy, GE Vernova, and Hitachi Energy, have entered into a partnership to develop direct current (DC) multiterminal hubs that are said to enable an efficient utilisation and distribution of large amounts of electricity generated by offshore wind farms.

“In the German North Sea alone, 70 gigawatts of offshore wind energy are planned, which must not only be brought ashore efficiently, but also distributed throughout the country in the most area- and cost-efficient way possible,” said Tim Meyerjürgens, COO of TenneT.

Through the newly established partnership, the German TSOs and the transmission technology companies plan to develop a common European standard for smart power hubs with the ultimate goal of connecting large DC lines in the future and creating a DC grid instead of straight point-to-point connections.

The joint project, which aims to demonstrate the technical feasibility and economic viability of the technology, plans for the first multiterminal hubs to be built in northern Germany. These will consist of a converter and a substation in addition to the DC switchgear, where the DC lines are linked together, enabling a regional supply of green energy.

The DC switchgear with DC circuit breakers is the centrepiece of the DC multiterminal hub technology which links direct current lines and flexibly transports the energy to where it is needed. For the first time, this will create extra-high voltage direct current (HVDC) power grids that will improve the utilisation of DC lines and, at the same time, support the existing alternating current (AC) grid as the backbone of energy transmission, TenneT states in a press release published on 15 July.

The DC circuit breakers are a technical innovation that, in the event of a fault, can identify faults in fractions of a second and switch off the affected areas, the TSO says.

Furthermore, the new way of linking the power lines allows for a reduction in the space and construction work required for new plants, minimising environmental impact and stabilising energy costs.

“Thanks to the innovative meshing of the power lines, we will minimise the space required and the construction of new plants in the future and keep costs stable for consumers – and thus promote acceptance of the energy transition. Without broad acceptance in society, the generational task of the energy transition cannot be shouldered,” said Werner Götz, CEO of TransnetBW.