A capacitive deionization (CDI) system for deionizing water is disclosed. The CDI system comprises at least a flow through capacitor (FTC) module, at least a first supercapacitor, at least a second supercapacitor, at least a third supercapacitor and a controller. The FTC module comprises a plurality electrodes for removing ions from water flowing between the electrodes under an electric field applied between the electrodes. The first supercapacitor is connected between the potential source and the FTC module for amplifying energy provided by the potential source. The second supercapacitor is connected to the FTC module for receiving energy from the FTC module for regenerating the electrodes of the FTC module. The third supercapacitor is adapted for exchanging energy with the FTC module for regenerating the electrodes of the FTC module. The controller is adapted for regulating deionization rate of the water and regeneration of the electrodes of the FTC module.