Objective Functions for Hydropower System Operation

Research was conducted to compare different objective functions and optimize complex hydropower operation systems. Six functions were considered covering a large number of possibilities: (FO1) minimize the loss of the stored potential energy, (FO2) minimize storage deviations from targets, (FO3) maximize total energy production, (FO4) minimize spilled energy, (FO5) minimize energy complementation, and (FO6) maximize the profit derived from secondary energy. The optimization was performed using the SISOPT model developed by a team of EPUSP and UCLA researchers and uses different methods to solve the operational problem. The optimization can be solved by Linear or Non-linear methods. The non-linear model was selected in order to get accurate results. The sub-system selected for case study was the Paranapanema System, located in the south of the State of São Paulo. The objective functions were analyzed considering different hydrological series. A set of data was obtained for comparative analysis. The results showed that generally the objective function used to minimize the complementation of energy demand in the entire system produces more suitable operation policies for the hydropower system.