Benefits of distributed energy storage working in parallel to distributed energy resources

In the context of new policies promoting the use of distributed energy resources (DER) the number of distributed generation (DG) units connected to the medium voltage (MV) and low voltage (LV) distribution grids has largely increased. Distribution companies offer different prices to DG owners depending on the signal quality and time-slot, because the price of sale of generated energy is influenced by the curve of the demand. The use of energy storage systems can help for a larger integration of DG controlling the power flow in the point of common coupling (PCC). From the economical point of view, the possibility to store the electricity when the price is low to sell when it is high makes energy storage an interesting investment for DG owners. In this article is discussed the use of distributed energy storage (DES), paying attention on the control requirements for a larger DG penetration and the economical benefits. The aim of the article is to develop a control strategy to increase economical profits assuring supply quality, for energy storage systems working in parallel to DG units.