Comparison of the ex-ante and ex-post methods for short-term reliability management

In this paper we compare the performance of two proposed methods for managing short-term reliability. First, we review the short-term reliability related risks associated with the possibility of transmission failures, which are measured through the probability of several scenarios and the respective consequences on some market participants. The load curtailment is used to evaluate the impact of failures on the customers. Second, we discuss two proposed methods for market-based reserve allocation, an ex-ante and an ex-post considering explicitly reliability requirements specified by the demand. Finally, we compare both methods in a test system where we show that they allocate reserve fulfilling pre-specified reliability requirements. The difference is in the amount of reserve allocated but not in the reliability level obtained. Moreover, the two methods differ with regard to stability of the electricity prices in presence of contingencies and the cost associated with different amounts of reserve.