“Netzbooster” for the high-voltage grid

TransnetBW operates the transmission grid in Baden-Württemberg (Independent Transmission Operator). With more than 3,200 kilometers of high-voltage lines, the EnBW subsidiary ensures that electricity is available everywhere in the southwest whenever it is needed. Operating the transmission grid used to be a relatively straightforward process. The electricity was distributed across the area from a few large power plants. However, due to the increasing amount of electricity being generated by the sun and wind, the entire energy system has become more complex. This presents the grid operators with considerable challenges.

A prime example: When it is windy, the wind farms in northern Germany produce a lot of electricity. The industries in the south of the country could really do with this. However, the line capacity is insufficient – leading to transmission congestion. Accordingly, less wind power is fed into the grid. In order to meet the demand in the south, conventional power plants generate the required electricity here instead. This measure – which experts refer to as “redispatching” – is expensive and often not particularly climate-friendly. In order to transport the required electricity from the north to the centers of consumption in southern Germany, TransnetBW is working with the three other transmission grid operators to build additional north–south high-voltage lines. At the same time, however, they are also working on measures to make better use of the existing grid.

The existing high-voltage grid capacity is by no means fully utilized at present. The reason for this is the number-one rule of grid operation, known as the (n-1) principle. This ensures that the power grid remains stable even if one transmission line fails, because the other lines can compensate for the outage and absorb the load. Since transmission line failures occur rather rarely, the “safety buffer” generally remains unused, which means that the individual lines transport significantly less electricity than would be possible.