NOVELTY - The method comprises feeding a concentrated ionic solution through a first pathway in a reverse electrodialysis (RED) unit (202) comprising a membrane stack having electrodes and alternating cation and anion exchange membranes, feeding a dilute ionic solution through a second pathway in the RED unit, and regenerating the concentrated and dilute ionic solutions from solutions exiting from the RED unit and recycling the regenerated concentrated and dilute ionic solutions back through the RED unit.    USE - The method is useful for generating electricity (claimed).    ADVANTAGE - The method ensures generation of the electricity in an energy efficient, environmentally-friendly, reliable, economical and rapid manner.    DETAILED DESCRIPTION - The method comprises feeding a concentrated ionic solution through a first pathway in a reverse electrodialysis (RED) unit (202) comprising a membrane stack having electrodes and alternating cation and anion exchange membranes, feeding a dilute ionic solution through a second pathway in the RED unit, and regenerating the concentrated and dilute ionic solutions from solutions exiting from the RED unit and recycling the regenerated concentrated and dilute ionic solutions back through the RED unit. A solute from the concentrated ionic solution migrates through the membranes to the dilute ionic solution. The method further comprises alternating which of the first and second pathways carries the concentrated and dilute ionic solutions, bringing one of said solutions into contact with a biocide and/or irradiating the solutions with UV-C light. The concentrated ionic solution and the dilute ionic solution differ in temperature by greater than or equal to 5 degrees C as they enter the RED unit, and independently have a temperature of 30-150 degrees C as they enter the electrodialysis unit. The ionic solutions comprise a salt and water. The method is performed such that S1/S2 is less than Y, where S1 is the mol/l concentration of solute in the concentrated ionic solution as it enters the RED unit, S2 is the mol/l concentration of solute in the dilute ionic solution as it enters the RED unit and Y is 30. The concentration of the dilute ionic solution is 0.06-2.5 mol/l. The concentrated solution and/or dilute solution comprise more surfactant, dispersant, pH buffer, anti-foaming agent and/or anti-corrosive agent. A flow velocity of the ionic solutions through the pathways is less than 4 cm/s. The concentrated and/or dilute ionic solutions comprise water and 0.02 mol/l of the solute. Half of the membranes including the support have a thickness of less than 250 mu m. Half of the cation exchange membranes comprise an ionically-charged polymeric layer obtained from a curable composition An INDEPENDENT CLAIM is included for a device for generating electricity.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic view of a method for generating electricity.    RED unit (202)    Regeneration unit (203)    Inlet (204)    Outlet (208)    Pump. (230)