The aim of the thesis was to describe and compare currently available energy storage technologies for the power system. The introduction describes the requirements of the obligation to encourage the use of energy from renewable sources to the Republic of Croatia as a signatory to the European climate and energy package. In the second part of the paper, the division of energy storage systems is made in accordance with the used technologies and energy storage time. Mechanical, thermal, electrical and chemical energy storage systems are studied in more detail through four chapters. Pump storage power plants, present for decades, are the most common technology in the world's power systems. Other technologies that use energy storage in mechanical are not overrepresented, although they are significantly more prevalent compared to thermal systems. Electrochemical systems, in the largest battery volume, with the development of technology find their application in all aspects of energy storage. In addition to lithium-ion, which have primacy in all segments, NaS batteries are important for the power system. If the system requires energy storage with a large number of cycles, electrical energy storage systems, a capacitor and a coil stand out as the best solution. Energy storage in the form of hydrogen and methane are quite similar processes, but due to more conversions, the efficiency of the methane production process is significantly lower. A great advantage of methane is the possibility of returning the gas as such to the gas network. Integrating renewable energy sources into the electricity system would not be possible without electricity storage technologies. Selecting the most appropriate technology for use in a particular location is a complex and demanding task in which it is necessary to consider a multitude of criteria that distinguish one technology over another.