Unit commitment in a hybrid diesel/wind/pumped‐storage isolated power system considering the net demand intra‐hourly variability

This paper presents a novel two‐stage stochastic mixed‐integer linear programming model for the generation scheduling of a hybrid diesel/wind/pumped‐storage power system that considers the intra‐hourly net demand variability during the first stage. The model aims to minimise the scheduling cost, calculates the power system storage opportunity cost and considers that the start‐up cost of thermal units depends on the time passed since the previous shutdown in a detailed manner for the first stage (i.e. using integer variables) and in an approximate manner (relaxing the integrality constraints) for the second stage. To increase the model's computational efficiency, a solution approach based on the Benders decomposition technique is applied. The model is implemented in the real power system of El Hierro island, an isolated hybrid diesel/wind/pumped‐storage power system with a closed‐loop pumped‐storage plant and high wind power installed capacity. The schedules provided by the proposed model are compared to the ones provided by a similar model that does not consider the intra‐hourly net demand variability, resulting in generation schedules with a significantly lower wind energy curtailment. The results demonstrate the importance of considering the intra‐hourly net demand variability in order to integrate more wind energy at a moderate extra cost.