Optimal sizing of distributed energy storage in distribution systems

In future smart grids, energy storage systems (EESs) are expected to play an indispensable role in balancing continuous load changes arising from customers’ life-style as well as varying output of intermittent energy resources. This, however, needs significant investment that should be justified prior to their implementation. This paper presents a model to find the optimal capacity for ESSs in distribution systems. The model aims at maximizing system owner profit by reducing total electricity procurement costs. The model is formulated as a mixed integer non-linear programming problem. Due to the complexity and large size of the problem, a decouplebased method is proposed wherein optimal charge/discharge pattern of ESSs is obtained via a quadratic programming (QP) model. The method is applied to the IEEE 33-bus network and simulation results are thoroughly discussed.