Effect of energy storage systems on optimal sizing of islanded micro-grid considering interruptible loads

In this paper a new methodology is proposed to evaluate the effect of energy storage systems on optimal size and total cost of an islanded micro-grid that consists of wind turbines, photovoltaic panels, fuel cells and the capacities of battery banks (as energy storage systems), interruptible and uninterruptible loads. When total of produced power in micro-grid can´t satisfy demand, first interruptible and then uninterruptible loads are interrupted. In this paper, the problem is formulated as a nonlinear integer minimization problem which minimizes the sum of the total capital, operational and maintenance and replacement costs of DERs (Distribution Energy Resources), penalty for interrupted loads. Effect of amount of maximum allowable depth of battery discharge (DOD) on optimal size and total cost of micro-grid are studied. This paper proposes Particle Swarm Optimization (PSO) for solving this minimization problem.