a method and apparatus for improving the water balance in the power unit by providing the exhaust gas from the cathode side of the pem fuel cell as a feed gas to the combustion system of the steam reforming system , condensing at least a portion of water present in the effluent from the combustion system in a condenser , and then transferring water vapor from the uncondensed portion of the effluent from the condenser to the gas fed to the cathode side of the pem fuel cell . water from the exhaust gas from the cathode side of the pem fuel cell is either captured in the condenser , or is reused in the feed gas of the cathode side of the pem fuel cell . by humidifying the air fed into system with the water vapor present in the exhaust gas , water is not lost from the system . instead , the air is being fed into the system is humidified with this water , which in turn allows the humidifier to operated at higher temperatures and / or use smaller radiators and fans and / or draw less parasitic power , thereby increasing overall system efficiency .