Optimal Participation of RES Aggregators in Electricity Markets Under Main Imbalance Pricing Mechanisms

This paper presents a wholistic approach to derive the optimal offering strategy of a price-taker RES aggregator in the day-ahead market. The day-ahead and the balancing market functions are analytically modeled, and fundamental imbalance settlement mechanisms are examined, namely Single Pricing, Two Price settlement and Dual Pricing. Several sources of uncertainty are considered affecting the day-ahead market prices, the imbalance prices and the actual production of the RES aggregator. To cope with these uncertainties, a stochastic risk-constrained optimization model is formulated for the aggregator's optimal bidding. A realistic application in the Greek power system allows for elaboration on the motivations for strategic bidding and accurate forecasting provided by each imbalance pricing scheme to the RES aggregator.