Comparison of methods for battery capacity design in renewable energy systems for constant demand and uncertain supply

Renewable energy systems such as solar and wind are notorious for their varying energy production. Joint use of a battery system can mitigate this problem to meet constant demand. In this paper, we compare three methods, namely, (i) Monte Carlo simulation based optimization, (ii) Stochastic programming, and (iii) Optimization using Storage moment equations of Fletcher and Ponnambalam to determine the relation between the battery system capacity versus available energy for use. The first two methods require a large number of samples while the last method uses only the statistical information. Each of these methods can also produce required probabilities of failures as a function of capacity and demand.