Home/Method notes/The north–south congestion index

Method note · estimate

The north–south congestion index

What it measures

A monthly index of surplus power in northern Germany that the south lacks, inside one price zone, which no border flow or price shows.

Inputs

  • SMARD's (the Bundesnetzagentur's market-data platform) balance, generation minus demand, for each of Germany's four control areas (a control area is the region one grid operator balances), daily
  • The redispatch volume for curtailed renewable output from netztransparenz.de, the German grid operators' joint data site, daily

Method and weighting

The index uses two inputs: each control area's daily balance (generation minus demand) from SMARD, and the curtailed volume from netztransparenz.de. For each local month, the northern surplus is the mean of the balance summed across the two northern control areas, and the southern deficit is the mean of the balance summed across the two southern ones. The congestion index is the smaller of the northern surplus and the size of the southern deficit: the surplus in the north that the south lacks at the same time, which the grid cannot move between them. Because that bottleneck sits inside the DE-LU bidding zone (Germany and Luxembourg, which share one wholesale price), it shows in neither the cross-border flow data nor the zonal price, and the view computes no price of its own. The same month's redispatch volume, the energy curtailed to relieve the bottleneck, sits beside the index without entering its calculation.

Window

Per local month, over the months the control-area balance and the redispatch volume cover. Data last refreshed on .

Known limits

  • The index is built from two monthly means, so it says nothing about any single hour.

Used on

Sources: SMARD, netztransparenz.de. Each is described on the Data sources page.