  We analyze the potential benefits that energy storage systems (ESS) can bring
to distribution networks in terms of cost, stability and flexibility. We
propose an optimization model for the optimal sizing, siting, and operation of
storage systems in distribution grids. A DistFlow formulation is used for
modeling the AC power flow. The ESS model is based on a generic formulation
that captures the charging and discharging modes' complementarity. The
resulting optimization model is stated as a mixed-integer quadratically
constrained program (MIQCP) problem. The optimization model is assessed on the
modified 33-bus IEEE network, which includes renewable energy resources and
ESS. The obtained results show that ESS can offer various important benefits
such as overall cost reduction, energy arbitrage, voltage regulation, and
congestion management in distribution grids. These findings highlight the
significance of utilizing ESS technologies to provide aggregated value through
various grid services, extending beyond energy arbitrage alone.
