This paper deals with primary types and classifications of energy storage systems. Even though there are various advanced solutions to this question this paper will firstly examine the most frequently used ones. In addition to descriptions of present-day systems the visual representation of them i salso shown. Since every system of storage has its own benefits and flaws it is necessary to elaborately analyze the systems in order to propose the appropriate one. Furthermore, this paper deals with the influence of the energy storage systems on the power grid in ways of its voltage and frequency stability in order to find out how to have more favorable conditions of the grid in relation to such systems. Ultimately the analysis of profitability and costs of energy storage system infrastructure is shown.