The Impact of Equalization Cycle on the Storage System Lifetime in PV-based Isolated Microgrids

Abstract

Lead-acid batteries are used predominantly for energy storage in isolated microgrids. In this application, they are subjected to frequent partial charge/discharge cycles, accelerating their loss of useful life. To mitigate this problem, it is necessary to apply periodic equalization charges using a dispatchable source (typically diesel generators). The use of this type of fuel is undesirable and should be minimized, requiring a commitment decision with the need to preserve the battery bank. This article investigates the frequency of these equalization charges to reduce the use of fossil fuel, while the battery bank's useful life is preserved. The result obtained is close to the empirical policies practiced in the operation of isolated microgrids in the equatorial region of Brazil.