Minimization of energy storage in a solar farm by controlling the state of charge of a battery bank

This paper presents a methodology for reducing energy storage requirements by using batteries to smooth out power variations of a solar farm. This reduction is achieved by combining the operation of an energy management system (EMS) with an optimally sized battery energy storage system (BESS). The capacity calculation of the BESS is determined by using an evolutionary algorithm. The EMS deploys a state-of-charge feedback (SOC-FB) control system to reduce the power variations of a solar farm, while the optimization algorithm determines the minimum required capacity of the BESS to keep the SOC in an acceptable range. This approach is tested by using real data from a small solar farm. Simulation results show a significant reduction of the power variation of the solar farm output, while the SOC of the BESS keeps within the operating range.