A fuel cell generator contains a plurality of fuel cells (11) in a generator chamber (20), where oxidant (13) and fuel (1) are fed to the generator chamber (20), where both fuel and oxidant react to form depleted fuel and depleted oxidant, which are separated by steam (2) at a pressure higher than that of both the depleted oxidant stream and the depleted fuel stream, and where all oxidant and fuel passages do not communicate with each other, so that fuel and oxidant (in whatever form) do not mix, and where depleted fuel (26), consisting essentially of carbon dioxide and water, exits for further treatment, so that the remaining carbon dioxide can be separated from the remaining water and is not vented to the atmosphere.