An Improved Statistical Approach to Generation Shift Keys: Lessons Learned from an Analysis of the Austrian Control Zone

Abstract

During market coupling, trading of electricity across borders is subject to capacity limits, provided by transmission system operators. Flow-based market coupling is the preferred method of the EU for cross-border capacity calculations. It is part of the EU’s design for a single electricity market to maintain security of supply and achieve competitive energy prices while integrating growing shares of renewable energy to reach the reduction targets for greenhouse gas emissions. The algorithm of flow-based market coupling incorporates the physical restrictions of critical network elements during market clearing. For this, Generation Shift Keys are required to translate nodal into zonal information by predicting, which generating units participate in import-export balance changes. This analysis presents an improvement of an existing approach to Generation Shift Keys, further developed within a study for the Austrian transmission system operators, Austrian Power Grid. The proposed method allows for Generation Shift Key estimations based on regression analysis and actual dispatch decisions, decoupled from fixed power plant characteristics and merit-order assumptions. The unit selection process based on economic significance leads to statistically significant and robust Generation Shift Keys in the majority of cases. The results highlight the importance of computing time-dependent, but not necessarily hourly Generation Shift Keys and indicate a limited positive correlation between participation in zonal changes and power plant capacities. Both aspects confirm the purpose of the developed model’s flexible and data-based properties.