This paper describes the model as well as the parameters of the battery for electrical energy. Areas of use, the most well-known types and degradation of the battery are described. In the practical part, an appropriate application was developed which shows the use of Battery Energy Storage in combination with renewable energy sources. The application has a dashboard with a display of production, consumption, price and amount of energy in Battery Energy Storage during 24 hours. Each storage can operate in three modes: peak shaving, price arbitrage and default mode. The most competitive Battery Energy Storage is considered to be the lithium-ion battery against which the degradation in the application is calculated.