Hybrid renewable energy systems (RESs), which usually combine photovoltaic, wind, biomass, and hydro power, are naturally variable. Since each source varies with time, it is unrealistic to assume reliability without storage. Storage balances intermittence, stabilizes voltage and frequency, and reduces generator stress by absorbing excess generation and releasing it when primary resources decline. Higher grid autonomy (or fully islanded operation), better power quality and continuity, and increased energy security against weather, price shocks, or interruptions are the specific benefits [1–5].