Hmm, I have never heard about gas vs electric moisture... Water evaporates at the same temp no matter the source, does it not? Is it that added humidity is naturally in the gas? Just curious.
Yes.... combustion of hydrocarbons always yields CO2 + H2O + heat. The quantities of each depend on the specific fuel though. Lighter hydrocarbons such as methane, the main constituent gas of natural gas, produce less heat per unit of H2O.
Thus also the reason why propane is preferred for gas grills. Higher energy content and less moisture.