NOVELTY - Energy storage and generation system comprises vessels for holding electrolyte and gas; stacks of regenerative fuel cells having housing with solid electrolyte membrane to partition it into anode and cathode side, where anode having support and dispersed with catalyst; and cathode is optionally dispersed with catalyst; where catalyst is capable of catalyzing, in presence of electrolyte or mixture of electrolytes, charging reaction and discharging reaction in regenerative fuel cells; which are connected with vessels to form electrolyte circulation loop and gas circulation loop.    USE - For generating and storing energy e.g. combination of flow battery and hydrogen fuel cell, useful for wide application with regenerative energy sources e.g. in matching a varying energy supply to varying energy demand.    ADVANTAGE - The system is capable of conducting both hydrogen evolution reactions and hydrogen oxidation reactions in the same system, thus providing low cost, fast response time, and acceptable life and performance system. The system comprises gas purifier containing catalyst which reduces or eliminate corrosive elements from the gas. The system exhibits operational stability in harsh environments e.g. both charging and discharging reactions in regenerative fuel cell in presence of halogen ion or mixture of halogen ions. Maintaining higher pressure on the hydrogen than on the electrolyte can have several advantages such as thermodynamic, kinetic, durability and safety. The carbon powder itself is an effective catalyst for the processes of reduction and oxidation.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following:    (1) maintaining different electrolyte and gas pressure within fuel cell stack involving sensing the pressure of electrolyte and gas within fuel cell stack; and controlling pressure of electrolyte entering fuel cell stack sufficient to maintain electrolyte pressure different from gas pressure within fuel cell stack; and    (2) storing and generating energy involving providing energy storage and generation system; storing energy by flowing electrolyte from vessel containing electrolyte to stacks of regenerative fuel cells; oxidizing electrolyte and producing hydrogen in stacks of regenerative fuel cells, and flowing hydrogen to vessel containing gas; and generating energy by flowing electrolyte from vessel containing electrolyte to stacks of regenerative fuel cells, flowing hydrogen from vessel containing gas to stacks of regenerative fuel cells, reducing electrolyte and oxidizing hydrogen in stacks of regenerative fuel cells.    DESCRIPTION OF DRAWING(S) - The figure shows block diagram of energy storage and generation system.