Blog July 03, 2019
 Figure 1: Wind and solar total output for first half of 2019 in Europe’s biggest markets, in TWh. Source: Genscape EPSI, Meteogroup
Figure 1: Wind and solar total output for first half of 2019 in Europe's biggest markets, in TWh. Source: Genscape EPSI, Meteogroup

Germany is undoubtedly the leader in Europe when it comes to the amount of electricity produced from solar and wind (Figure 1). About 95 percent of this electricity is sold on the wholesale market by direct marketing companies (Direktvermarkter) on behalf of renewable asset owners and operators.

However, the impressive growth in supply from renewable sources in Germany is increasingly constrained by transmission network limits, which we highlighted in our previous blog. On the days with high wind and solar production, the network reaches its capacity limits and congestion occurs.

Congestion can occur on medium-voltage lines operated by Distribution System Operators (DSOs) or high-voltage lines operated by Transmission System Operators (TSOs). Currently, six DSOs deal with the challenge of network congestion caused by high renewable feed-in: Avacon, Bayernwerk, E.DIS, Mitnetz, Schleswig-Holstein, and Wemag. Tennet and 50Hertz are TSOs who experience the same issue on their respective networks.

To alleviate the congestion and secure the network, the electricity grid operator, either DSO or TSO, reduces or switches off production from a wind- and solar installation. This is done as a last resort measure and is known as feed-in management (Einspeisemanagement) or “Einsman.” When this happens, the operator or owner (Betreiber) of the affected asset is compensated by the grid operator for lost revenues.

Although this seems like a fair arrangement, up to 95 percent of renewables are marketed by direct marketing companies. They are not compensated by grid operators, but are left with a supply shortage in their portfolio that they are required to balance. To avoid prohibitively high imbalance costs, direct marketing companies will try to use the Intraday market to balance their position. According to Intraday market rules, this can be done up to five minutes before physical delivery.

Is there enough time for a direct marketing company to act on an Intraday market when Einsman takes place?

In the case of necessary adaptation of power feed-ins and power take-offs, German regulation requires the affected operators and electricity traders to be informed as far in advance as possible. The TSO or DSO often applies Einsman very close to physical delivery and without an indication of duration or end time. This complicates the job of direct marketing companies.

Direct marketing companies try to anticipate when Einsman will happen using Einsman forecasts that are primarily based on weather-driven renewable generation forecasts. While helpful, these forecasts do not provide visibility on the actual line flows or congestion, nor indicate when the Einsman measure will be lifted.

Using our proprietary monitoring technology, we furnish alerts when a flow reaches the line’s capacity and when the congestion is relieved. This provides direct marketing companies with actionable information when Einsman measure may be applied on their assets and when the measure may be removed again.

Figure 2: Map of 110KV lines in Schleswig-Holstein network with identified bottlenecks. Source: Schleswig-Holstein Netz
Figure 2: Map of 110KV lines in Schleswig-Holstein network with identified bottlenecks. Source: Schleswig-Holstein Netz

We are in the process of expanding our coverage to track physical flows on critical lines in real-time and to capture bottleneck areas in northern Germany, for example as shown on the grid map for Schleswig-Holstein area (Figure 2).

For more information, please visit Genscape’s proprietary monitoring technology pages or our European power market solution pages.