Ion exchange membrane fuel cell power plant with water management pressure differentials

A method for operating a solid polymer electrolyte membrane fuel cell power plant, said method comprising the steps of:

• a) providing oxidant and fuel reactant gas streams on opposite cathode and anode sides of the solid polymer electrolyte membrane;
• b) providing a circulating water coolant stream in communication with said cathode side and anode side of the electrolyte membrane;
• c) providing fine pore plates between said oxidant gas stream and said circulating water coolant stream and between said fuel gas stream and said circulating water coolant stream
• d) setting said oxidant reactant gas stream at a first predetermined pressure;
• e) setting said water coolant stream at a second predetermined pressure which is less than said first predetermined pressure so as to create a positive target pressure differential (.DELTA.P) between said oxidant reactant gas stream and said water coolant stream, which .DELTA.P is operative to pump water appearing on the cathode side of the electrolyte membrane through one of said fine pore plates and into said circulating water coolant stream;
• and
• f) setting said fuel gas stream at a predetermined pressure relative to the coolant stream pressure which will allow coolant water to be delivered to or removed from the anode side of the membrane.