Balancing Power Markets in Germany: Timing Matters

This paper analyzes timing issues on the German balancing power market. We focus the analysis on the length of the bidding period, i.e. the length of the time period a supplier has to provide balancing power capacities, and the question of how far before the beginning of a bidding period the auction should be carried out. We show that different load levels require different plants for the optimal provision of balancing power. In a longer bidding period, the power plants that have the lowest average cost in the bidding period are unlikely to be efficient in all hours of the bidding period. Hence, shortening bidding periods can increase efficiency. Furthermore, we show that an early commitment on a power plant’s mode of operation (when uncertainty about resulting spot prices is still relatively high) also reduces efficiency. This suggests that the auction should be held relatively close to the beginning of the bidding period. Furthermore, we discuss some advantages of a liquid real time market.