Performance Analysis of Dual-Storage System for Isolated Microgrids based on Tidal Stream Source

Due to the intermittent characteristic of renewable sources, battery energy storage systems (BESS) play an important role in instantaneous power balance. In isolated microgrids, leadacid batteries are still widely used as storage and their useful life is directly related to the way they operate. The pattern of renewable sources contributes to the loss of battery life. One way to mitigate this problem is to use a dual battery energy storage system (DBESS), which enables better integration between renewable generation source and storage devices. However, this strategy depends on the characteristic of the renewable source and in the case of tidal stream plants, its benefits have not been evaluated yet. In this paper, we use a DBESS composed of two storage subsystems with different functions and subjected to different charging/discharging conditions, according to the pattern of the tidal current source. A comparison is made between tidal and photovoltaic sources, evaluating the benefits of a DBESS microgrid. The Schiffer model is used to estimate the battery life as a way to evaluate the benefits of the applied strategy.