Method for temporary storing electrical energy in an energy storing system, the energy storing system comprising: - an electrolysis unit for producing hydrogen and oxygen, - a hydrocarbons reactor unit for producing hydrocarbons and water and - a secondary electrical energy generator for producing secondary electrical energy and carbon oxide, wherein - the electrolysis unit is connected to the hydrocarbons reactor unit to supply the hydrogen produced by the electrolysis unit to the hydrocarbons reactor unit, - the electrolysis unit is connected to the secondary electrical energy generator to supply the oxygen produced by the electrolysis unit to the secondary electrical energy generator, - the hydrocarbons reactor is connected to the secondary electrical energy generator to supply the hydrocarbons produced by the hydrocarbons reactor unit to the secondary electrical energy generator and - the secondary electrical energy generator is connected to the hydrocarbons reactor unit to supply the carbon oxide produced by the secondary electrical energy generator to the hydrocarbons reactor unit, the method comprising at least the following steps: - Providing primary electrical energy, - Operating the electrolysis unit to produce hydrogen and oxygen, - Operating the hydrocarbons reactor unit to produce hydrocarbons and water, - Operating the secondary electrical energy generator to produce secondary electrical energy and carbon oxide, - Supplying the hydrogen produced by the electrolysis unit to the hydrocarbons reactor unit, - Supplying the oxygen produced by the electrolysis unit to the secondary electrical energy generator, - Supplying the hydrocarbons produced by the hydrocarbons reactor unit to the secondary electrical energy generator, - Supplying the carbon oxide produced by the secondary electrical energy generator to the hydrocarbons reactor unit, - Using the primary electrical energy to operate the electrolysis unit, - Using the supplied hydrogen and the supplied carbon oxide to operate the hydrocarbons reactor unit and - Using the supplied hydrocarbons and the supplied oxygen to operate the secondary electrical energy generator, characterized in that the secondary electrical energy generator comprises a piston engine, wherein the oxygen produced by the electrolysis unit and the hydrocarbons produced by the hydrocarbons reactor unit 1 are combusted to operate the piston engine and in that the system is operated as closed loop to which only the primary energy is provided. - an electrolysis unit for producing hydrogen and oxygen, - a hydrocarbons reactor unit for producing hydrocarbons and water and - a secondary electrical energy generator for producing secondary electrical energy and carbon oxide, wherein - the electrolysis unit is connected to the hydrocarbons reactor unit to supply the hydrogen produced by the electrolysis unit to the hydrocarbons reactor unit, - the electrolysis unit is connected to the secondary electrical energy generator to supply the oxygen produced by the electrolysis unit to the secondary electrical energy generator, - the hydrocarbons reactor is connected to the secondary electrical energy generator to supply the hydrocarbons produced by the hydrocarbons reactor unit to the secondary electrical energy generator and - the secondary electrical energy generator is connected to the hydrocarbons reactor unit to supply the carbon oxide produced by the secondary electrical energy generator to the hydrocarbons reactor unit, - the electrolysis unit is connected to the hydrocarbons reactor unit to supply the hydrogen produced by the electrolysis unit to the hydrocarbons reactor unit, - the electrolysis unit is connected to the secondary electrical energy generator to supply the oxygen produced by the electrolysis unit to the secondary electrical energy generator, - the hydrocarbons reactor is connected to the secondary electrical energy generator to supply the hydrocarbons produced by the hydrocarbons reactor unit to the secondary electrical energy generator and - the secondary electrical energy generator is connected to the hydrocarbons reactor unit to supply the carbon oxide produced by the secondary electrical energy generator to the hydrocarbons reactor unit, - Providing primary electrical energy, - Operating the electrolysis unit to produce hydrogen and oxygen, - Operating the hydrocarbons reactor unit to produce hydrocarbons and water, - Operating the secondary electrical energy generator to produce secondary electrical energy and carbon oxide, - Supplying the hydrogen produced by the electrolysis unit to the hydrocarbons reactor unit, - Supplying the oxygen produced by the electrolysis unit to the secondary electrical energy generator, - Supplying the hydrocarbons produced by the hydrocarbons reactor unit to the secondary electrical energy generator, - Supplying the carbon oxide produced by the secondary electrical energy generator to the hydrocarbons reactor unit, - Using the primary electrical energy to operate the electrolysis unit, - Using the supplied hydrogen and the supplied carbon oxide to operate the hydrocarbons reactor unit and - Using the supplied hydrocarbons and the supplied oxygen to operate the secondary electrical energy generator, characterized in that