Optimal operation of reservoirs for electric generation

Several tests have been performed with a simple test system under special conditions in order to highlight the influence of several factors including water head, discount rate, inflow seasonality, and system design. According to the results, reservoirs should operate at the highest possible storage level in order to maximize the generation efficiency of their associated power plants. This conservative behavior is shown to be the most economic for generation purposes. On the other hand, in a cascade system, the water head factor has the effect of specializing the behavior of the reservoirs. Reservoirs in the upper part of the cascade should play a regulation role while in the lower part of the cascade they should operate as run-of-river plants. These results have been verified on an actual large-scale hydroelectric system, the Brazilian South-Southeast Interconnected Electric System, composed of 51 hydro plants and 31 reservoirs