SuedOstLink

As high-voltage direct current (HVDC) connection the new SuedOstLink will transport up to 2,000 megawatts of electrical power over 580 kilometers from northern to southern Germany.

The SuedOstLink will reach from the area of Saxony-Anhalt to the south of Bavaria. Connecting these regions, means connecting the north with its large surplus of wind-power in the north with the industrialised south, where the nuclear plants are phased out successively during the coming years.

Compared with the common alternating current (AC) transmission, the HVDC technology is more suitable to transport large amounts over long distances. And although converter facilities at both ends of the line are required, transmission losses are far lower compared with the common AC standard, as no reactive power compensation is required. Additionally, the amount of power as well as the direction of transmission can be controlled. Limitation: Today the DC technology only allows point-to-point transmission, meshed grids known from AC standard are subject to development.

The need for the transmission capacity of SuedOstLink is approved by the Federal Network Agency’s (Bundesnetzagentur) network development plans from 2012 on. As project number 5 it is also part of the Federal Requirements Plan Act, passed by the German Federal Parliament (Bundestag) as well as the Federal Council (Bundesrat).

By the end of 2015 the two federal chambers have also approved changes to the Federal Requirements Plan Act. These changes defined Wolmirstedt near Magdeburg instead of Lauchstädt (both state of Saxony-Anhalt) and Isar near Landshut instead of Meitingen (both federal state of Bavaria) as grid connection points. The SuedOstLink will primarily be constructed by underground cabling, sections with overhead lines are subject to specific exceptions. Before the amendment the connection was planned as overhead-line.

The start and end points, i.e. Wolmirstedt and Isar near Landshut, define a new survey area, in which 50Hertz has determined suitable route corridor variants for the SuedOstLink together with its project partner, fellow transmission system operator TenneT. These corridors are 500 to 1,000 metres wide and their various combinations connect the start and end point of the line construction project.

In the first half of 2017, the project developers submitted documents for federal sector planning to the Federal Network Agency for the project, subdivided into four sections A to D. These documents contain a so-called corridor proposal as the connection between Wolmirstedt and Isar considered the most favourable by the project developers. The application furthermore contains different serious alternatives. In order to determine these routes, the project developers considered over 60 factors, including residential areas, nature conservation areas and possible bundling options. The final decision on the corridor is made by the Federal Network Agency in its decision on the federal sector planning.

During the second step, the so-called plan approval procedure, the specific details on the execution of the actual route are determined. These include the exact course of the underground cable, the location of the cable connections, or in case of overhead line sections, specific tower locations. Also decided at this stage are adequate compensatory and replacement measures. This procedure, too, is handled by the Federal Network Agency.

More information on the basic course of the procedure

The new grid connection points, Wolmirstedt near Magdeburg and Isar near Landshut, have defined a new planning region. Here the project partners, 50Hertz and TenneT, identified suitable route corridor alternatives. These route corridors are up to 1,000 meters wide and connect Wolmirstedt and Isar in various combinations.

50Hertz and TenneT have submitted their application documents successively in four sections during first and second quarter of 2017. Following, the official Federal Sectoral Planning (Bundesfachplanung) for SuedOstLink started. Responsible authority is the Federal Network Agency. At the end of the planning procedure the authority will define one mandatory route corridor between Wolmirstedt with Isar. At this stage Federal Network Agency will also decide if sections with partial DC overhead lines are to be realised.

In a second step, a following planning approval process (Planfeststellungsverfahren) defines the exact routing of the cables or overhead lines within the approved corridor. Also mitigation and compensation measures are specified at this stage. This approval process is led by the Federal Network Agency.