NOVELTY - A metal-water reaction is used to generate hydrogen in situ, and the reaction products are collected and transported to a regenerator where the oxidized metal is reduced to a metallic material for returning to the hydrogen producing system.    USE - For supplying electricity to a remote area without access to a power grid, or for providing a back-up power supply (claimed).    ADVANTAGE - Hydrogen can be produced on demand using a cost-effective, environmentally-friendly system operating at temperatures below 100 degreesC, enabling electricity to be generated by a cost-effective and environmentally-friendly method in areas without access to a power grid or where a back-up electricity supply is needed.    DETAILED DESCRIPTION - A method for generating electricity using at least one hydrogen-powered electricity generating device, comprises transporting a metallic material to a hydrogen producing system in which a metal-water reaction is used to generate hydrogen in situ, collecting the reaction products and transporting them to a regenerator where the oxidized metal is reduced to a metallic material, and returning the metallic material to the system. INDEPENDENT CLAIMS are also included for (a) a hydrogen generating system including a metal-water reactor comprising an electrochemical cell housed in a reaction vessel (20) whose anode (21) comprises a removable module containing a metallic material and a small amount of solid acid, this module being adapted to be transported to a regenerator once it is depleted, (b) a regenerator for regenerating fuel, comprising an electrolytic cell with two electrodes held apart from each other and in contact with an aqueous electrolyte capable of producing a porous metallic material by electrolytic deposition, and (c) a method of producing hydrogen using the above system, in which a module comprising a metallic material and a solid acid is placed inside the reaction vessel, an aqueous electrolyte (23) is allowed into the vessel, the reaction products are separated from the water and collected in a portable container, and the container is transferred to a regenerator for converting oxidized metal into a metallic material.    DESCRIPTION OF DRAWING(S) - Figure 2 shows a metal-water reactor.    Reaction vessel (20)    Anode (21)    Cathode (22)    Electrolyte (23)    Separator (24)    Space above electrodes (25)    Gas valve (26)    Electrolyte reservoir (27)    Cables (28)    Variable resistor (29)