In various aspects, systems and methods are provided for operating a molten carbonate fuel cell with an excess of reformable fuel relative to the amount of oxidation performed in the anode of the fuel cell. Instead of selecting the operating conditions of a fuel cell to improve or maximize the electrical efficiency of the fuel cell, an excess of reformable fuel can be passed into the anode of the fuel cell to increase the chemical energy output of the fuel cell. This can lead to an increase in the total efficiency of the fuel cell based on the combined electrical efficiency and chemical efficiency of the fuel cell.