A novel electrochemical conversion scheme for the spontaneous and simultaneous production of carbon-free hydrogen and electric power is proposed and modeled. The design combines a carbon fuel cell and a steam-carbon fuel cell into a steam-carbon-air fuel cell that shares a single solid carbonaceous fuel bed in the anode chamber. A model of the combined cell is developed and a new definition for overall cell efficiency, which accounts for the hydrogen product generated, is produced. Results indicate that the proposed cell can reach efficiencies above 78%, and can also realize a six-fold increase in hydrogen production rate compared to a steam-carbon fuel cell with only a doubling of the cell active area. (C) 2012 The Electrochemical Society. [DOI: 10.1149/2.032212jes] All rights reserved.