Properties of small-scalle flow battery for prosumer-owned microgrid

Rising penetration of intermittent renewable energy sources (RES) having variable nature became the challenge for distribution grids operators to maintain voltage quality inside permissible range. It requires involving of new distributed resources like energy storage devices for smoothing power fluctuations of RES and to avoid of long-term voltage rising. To achieve best results they should be located as close to micro source as possible - behind the meter. Small, distributed energy storage devices help increasing self-consumption of energy generated inside microgrids causing also flattening of daily load curve of electrical power system (EPS). This paper discusses the properties of selected energy storage technologies suitable for small-scale microgrids containing renewable energy sources. Especially, the properties of small Zinc Bromine (ZnBr) flow battery obtained in experimental research have been presented and compared to the properties of other energy storage devices classified to similar classes but being on different maturity and development level. The simple equivalent model of ZnBr battery has been developed and described as well.