Contribuições para a operação energética e econômica de microrredes isoladas com fontes renováveis

Abstract

The development of microgrids was driven by the need to supply consumers with more stable and reliable electricity. The intermittent nature of renewable sources differs from the requirements of consumers - especially in isolated areas - who expect an uninterrupted and quality energy supply. Isolated microstrips may have available one or more renewable sources to be explored, configuring hybrid systems. Although such renewable sources are inexhaustible, energy conversion systems are capacity limited and need to be explored efficiently. Hybrid systems typically include solar photovoltaic and wind, already well studied. In this thesis are introduced the oceanic energies in their gradient and tidal currents forms. This thesis contributes to the efficient exploration of the oceanic sources, both as a single source as well as in a hybrid configuration. In relation to the isolated operation, the storage system is of fundamental importance. Considering the high costs of a battery bank over the total cost of the system, operating strategies that preserve its useful life while maintaining uninterrupted power supply are mandatory. Considering these aspects, in this work is proposed a dual energy storage system composed of two subsystems with diversified functions and submitted to different chage/discharge conditions. The purpose of this new strategy is a more efficient use of the storage system, since this operating regime becomes closer to the recommended by the battery manufacturers. The benefits of this strategy are reflected in the overall cost reduction of the microgrid. In order to achieve optimum operating strategies, a more accurate mathematical model of the batteries is used to reproduce the behavior of the batteries in a more realistic way. In addition, it is investigated the performance of operating strategies that allow maximum benefits to be obtained through the diversification of the microgrid energy matrix, by including hydrokinetic tidal sources. The motivation for including this source lies in its high potential, especially on the northern coast of Brazil. These benefits should be evaluated mainly through the more efficient use of the storage system as well as the reduction of the participation of fossil fuel units in the operation of isolated microgrids.