An generator that uses on the heat of condensation of water vapor as an energy source to produce electrical power. A hygroscopic, membrane electrode assembly is configured having an ion conductive hygroscopic electrolyte sandwiched between a pair of electrodes. One electrode is in contact with the water and the other electrode being in contact with a water vapor source whereby an electrochemical potential differential is produced across an electrical load by the reaction potential of the hygroscopic electrolyte with water vapor relative to the electrolyte's reaction potential with the liquid water. Power is supplied to an external load connected between the electrodes with water vapor being electrolyzed at the electrode that is in contact with water vapor and liquid water being reduced at the electrode that is in contact with liquid water.