The transmission grid between the substations of Eula near Leipzig (Saxony), Weida (Thuringia) and Herlasgrün (Saxony) in the Vogtland region as well as the Marktleuthen/Kirchenlamitz survey area in Bavaria is facing a generation change. The current 220-kV overhead line will be replaced with a powerful 380-kV overhead line (replacement construction). From Herlasgrün up to the Marktleuthen/Kirchenlamitz survey area, a new 380-kV overhead line will also be built.
50Hertz is implementing the Eger-Elster overhead line project up to the border of Saxony with Bavaria. The responsible project developer for the section from the Bavarian border up to the Marktleuthen/Kirchenlamitz survey area in Bavaria is transmission system operator TenneT. The project thus interlinks the control areas of the two transmission system operators 50Hertz and TenneT. The line is therefore a so-called interconnector.
The future Eger-Elster line is intended to increase the transmission capacity as well as the regional and cross-regional security of supply. The existing 220-kV line is outdated. Moreover, its transmission capacity is too low for the transmission needs to be expected as a result of renewable growth. That is why 50Hertz is planning the conversion to the contemporary voltage level of 380 kV and an increase of the current-carrying capacity to 4,000 amperes. This also involves modernising the connected substations and transformers. Furthermore, the already existing 380-kV lines between Thuringia and Bavaria are subject to unduly high loads. The southern section therefore needs the construction of a 380-kV overhead line.
In the future, the increased capacity of the Eger-Elster line will also make an important contribution to the energy transition: the line will feed regionally generated renewable energy into the extra high voltage grid and transport it to the demand regions in the south. As a result of the growth in renewable energy in Thuringia, Saxony and Bavaria, there is an increasing need for capacity to feed in electricity from the local distribution grid. Moreover, the line contributes to lowering the redispatch costs.2
The replacement construction of the northern and middle sections follows the NOVA principle (grid optimisation before upgrade before expansion) and is classified accordingly as a grid upgrade. The southern section involves new line construction.
The commissioning of the Eger-Elster line will take place section by section and is planned for 2037. To ensure the electricity supply, the old line needs to remain in service until the new line is commissioned.