Аннотация:The review deals with the modern systems of energy accumulation, including all basic systems of the kind and perspective systems as well. The importance of the development of modern systems of energy accumulation and, first of all, large-scale systems of electric power accumulation is attributed to the wide introduction of renewable energy sources (RES) worldwide over the past few decades as well as serious problems in the western countries due to the provision of high-quality, continuous and break-even generation of electric power from the sources above. A desirable transition to environmentally clean electric transport in the future also provides for the compact, capacious and powerful systems of electricity accumulation (about 100 kW.h and above) of lower costs, high reliability and ecological compatibility. All basic systems of energy storage are examined in the review - from the giant hydro-accumulating power stations requiring heavy capital investments which in principle are the most suitable for cooperation with RES -to the compact electrochemical systems of all basic types, including in-use and perspective modifications of lithium accumulators, fuel cells, redox-cells, and modern super capacitors. A detailed analysis of self-discharge is also carried out in all basic types of the reviewed systems of energy accumulators with a special emphasis on self-discharge of electrochemical systems of electric power accumulation with the selection of the most perspective ones. An emphasis has also been laid on the modern systems of electric power accumulation based on reversible fuel cells and, first of all, the systems of the so-called hydrogen cycle, including combined systems "fuel cell-electrolyzer" to generate charging/ discharging processes in a single unit.