A power generator and method include passing ambient air via an ambient air path past a cathode side of the fuel cell to a water exchanger, picking up water from the cathode side of the fuel cell and exhausting air and nitrogen to ambient, passing hydrogen via a recirculating hydrogen path past an anode side the fuel cell to the water exchanger, where the water exchanger transfers water from the ambient air path comprising a cathode stream to the recirculating hydrogen path comprising an anode stream, and passing the water to a hydrogen generator to add hydrogen to the recirculating hydrogen path and passing the hydrogen via the recirculating hydrogen path past the anode side of the fuel cell.