Expectation-based reserve capacity dimensioning in power systems with an increasing intermittent feed-in

The ongoing transition process of the European electricity sector to an increasing share of renewable electricity generation is in full swing. Unavoidable forecast errors of non-dispatchable energy sources (e.g. wind and solar power) have to be balanced out by reserve capacity power plants. This is normally organized in markets for ancillary services. Whereas the necessary reserve capacity, calculated by the transmission system operator (TSO), was historically dimensioned on a monthly basis, not considering information on the forecasted feed-in of the fluctuating generation from RES, this will change in future. Consequently this paper intents to present a methodology for an expectation-based reserve capacity dimensioning, based on a method currently applied by many of the European TSO. The results show, that by application of the methodology in an exemplary European case study for the year 2022, the necessary average reserve capacity decreases. However, the hourly demand for tertiary reserve capacity is subjected to significant fluctuations, due to volatile wind and solar generation.