As integrated fossil fuel power plant and a method of operating the power plant is provided. The integrated fossil fuel power plant includes a gas turbine arrangement and a carbonate fuel cell having an anode side and a cathode side. The operating method for the integrated fossil fuel power plant includes partially expanding combustion gases in the gas turbine arrangement so that the temperature of the partially expanded combustion gases is optimized for reaction in the cathode side of the carbonate fuel cell, and feeding the partially expanded combustion gases at the optimized temperature to the cathode side of the carbonate fuel cell for reaction in the cathode side of the carbonate fuel cell.