NOVELTY - The procedure and device for storing electrical energy in large scale, comprise a water-electrolyzer and a hydrogen-oxygen fuel cell (7) and/or a storage container (2, 3) for hydrogen and oxygen. The water-electrolysis is carried out to hydrogen and oxygen in alkaline pressure electrolyzer and the recombination of hydrogen and oxygen to electric energy and water in the alkaline fuel cell. The total system is sealed out of alkaline electrolyte, reaction water and/or hydrogen and oxygen hermetically against the external air.    USE - Procedure and device for storing electrical energy on large scale.    ADVANTAGE - The procedure and device increase peak capacity of the relevant part network and improve the economy through profitable sale of peak current and power quality by regulation of load peaks and stabilization of network voltage and network frequency and/or through reduction of harmonics.    DETAILED DESCRIPTION - The procedure and device for storing electrical energy in large scale, comprise a water-electrolyzer and a hydrogen-oxygen fuel cell (7) and/or a storage container (2, 3) for hydrogen and oxygen. The water-electrolysis is carried out to hydrogen and oxygen in alkaline pressure electrolyzer and the recombination of hydrogen and oxygen to electric energy and water in the alkaline fuel cell. The total system is sealed out of alkaline electrolyte, reaction water and/or hydrogen and oxygen hermetically against the external air. The storage container for hydrogen and/or oxygen is used with the reaction water for the storage. The storage container is arranged above the electrolyzer so that the water flows under natural dip in the electrolyzer. The storage container is arranged above the electrolyzer so that the water flows under natural descent in the electrolyzer. The reaction water is separated from the electrolyzer to obtain a constant concentration of the electrolytes. The reaction water is not separated from the electrolytes and the electrolyte storage is measured so that the variations in the concentration of the electrolyte remain through different water contents in different process condition in an area acceptable for the electrolyzer and the fuel cell. The storage container is held for the electrolyte in complete filling condition and small variations are intercepted over a hermetically tight membrane-compensator reservoir. The fuel cell flows throughable by electrolyte in circulation to dissipate the reaction warm and the reaction water. The fuel cell is arranged within the electrolyte storage container so that the electrolyte flows under natural descent in the electrolyte storage container. A heat exchanger (8) is arranged for the removal of reaction warm in the electrolyte circulation and/or in the electrolyte storage container. The fuel cell is implemented as falling-film fuel cell and the electrolyzer is implemented as falling film electrolyzer. The fuel cell and the electrolyzer are connected over a joint electronic power system with current supply system. The electronic power system in discharging mode works as controlled inverter and in charging mode as controlled rectifier. The power adjustment of the fuel cell is caused only by variation of the obtained direct current. The electrolyzer and the fuel cell are summarized to a regenerative electrochemical transformer. An INDEPENDENT CLAIM is included for procedure for safety checking of fuel cell.    DESCRIPTION OF DRAWING(S) - The figure shows a device for storing electrical energy in large scale (Drawing includes non-English language text).    High pressure electrolyzer (1)    Storage container (2, 3)    Pressure regulator (6)    Fuel cell (7)    Heat exchanger. (8)