A sodium chlorate electrolysis cell (9) receives a portion of its electrical power (47, 48; 50, 51) from a phosphoric acid fuel cell (45) which receives fuel at its anode inlet (43) from a water cooled catalytic reactor (26) that converts oxygen in the byproduct output (21) of the sodium chlorate electrolysis cell to hydrogen and water. A utility grid (53) may provide through a converter (55) power to support the electrochemical process in the sodium chlorate electrolysis cell. Temperature of the water cooled catalytic reactor is determined by the vaporization of pressurized hot water, the pressure of which may be adjusted by a controller (36) and a valve (38) in response to temperature (40).