NOVELTY - Reverse electrodialysis device comprises electrolyte compartments formed between cation exchange membranes (c) and anion exchange membranes (a). Low-osmotic electrolyte solutions with low electrolyte concentrations and high-osmotic electrolyte solutions with electrolyte concentrations higher than the low-osmotic electrolyte solutions are placed alternately in the electrolyte compartments. The device includes a device for limiting transport of multivalent ions from the low-osmotic electrolyte solutions to the high-osmotic electrolyte solutions.    USE - Device for reverse electrodialysis process for generating electric energy.    ADVANTAGE - The device prevents reverse transport of multivalent ions.    DETAILED DESCRIPTION - A reverse electrodialysis device comprises anode compartments having an anode (1) which is placed in an anode fluid comprising reagents for an oxidation reaction; cathode compartments having a cathode (2) which is placed in a cathode fluid comprising reagents for a reduction reaction; cation exchange membranes (c) and anion exchange membranes (a) placed alternately between the cathode and anode. Electrolyte compartments are formed between cation exchange membranes and anion exchange membranes. Low-osmotic electrolyte solutions with low electrolyte concentrations and high-osmotic electrolyte solutions with electrolyte concentrations higher than the low-osmotic electrolyte solutions are placed alternately in the electrolyte compartments. The device includes a device for limiting transport of multivalent ions from the low-osmotic electrolyte solutions to the high-osmotic electrolyte solutions. An INDEPENDENT CLAIM is included for a method for generating electric energy, comprising allowing the low-osmotic and high-osmotic electrolyte solutions to flow through the electrolyte compartments; and electrically connecting the anode and the cathode.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic overview of the device for performing reverse electrodialysis process.    Anode (1)    Cathode (2)    Electric circuit (3)    Anion exchange membranes (a)    Cation exchange membranes (c)