Redispatch patterns of energy market and reserve power plants in Germany

The increase in variable renewable energy generation, the ongoing coal and nuclear phase-out and delays in network expansion require system operators to undertake congestion management measures. In Germany, besides the redispatch from units in the energy-only-market, transmission system operators use additional congestion management measures such as feed-in management (i.e. redispatch of units receiving subsidies) and the operation of reserve power plants. While activation drivers and patterns for the redispatch of energy market units and feed-in management have been studied, this paper highlights the interplay between redispatch actions using market units and reserve power plants. Results show slower and anticipated redispatch activation patterns of reserve power plants compared to market power plants. In the context of the nuclear and coal phase-out, the introduction of a new congestion management scheme in October 2021 and further European market integration, the results raise the question on the future role of the network reserve.