Ex-Post-Analysis
The fundamental role of the grid reserve in the Austrian power system in 2025 and 2026
According to its statutory mandate in §143(3) ElWG (Austrian Electricity Law) APG carries out an annual system analysis to determine the expected demand for flexible capacity in the Austrian transmission system two years in the future. To assure the high quality of this complex analysis, a yearly ex-post-analysis on the historical demand for congestion management and grid reserve is performed in accordance with §143(3) ElWG) and §7(2) Netzreserve-Verordnung. The results of the ex-post-analysis are to be considered in the following system analysis via adjustments to the methodology or ingoing assumptions, if indicated.
The ex-post-analysis shows the fundamental role of the grid reserve in the assurance of the grid security and security of supply in Austria in the period of January 1, 2025, to June 30, 2026. The European and Austrian energy sector is characterized by a rising volatility due to the advanced availability of renewable energy sources in the power system and the increasingly palpable consequences of climate change. Simultaneously, more and more thermal power plant operators intend to shut down or permanently close their power plants. Therefore, the importance of hedging measures in the form of securely available flexible capacity remains unbroken.
The grid reserve was needed for congestion management throughout 2025 and 2026. Between July 2025 and June 2026, the frequency of grid reserve deployments doubled in comparison to the year before in part due to the extreme drought in this period in Austria. The necessity of the grid reserve is clearly illustrated particularly in the detailed analysis of single historical critical hours. The ex-post-analysis shows these historical situations occur frequently and show large similarities with the simulations of the system analysis. Congestion management is a highly complex process in the operation of a transmission grid. Especially in critical situations, the grid reserve is necessary as a reliable, securely available tool to ensure the safe operation of the Austrian power grid.