The essay introduces a comprehensive equation for the exergetic total efficiency of a gas/steam process. At the same time, it considers the thermal efficiency and the heat removal from the gas and steam process, the additional firing of the exhaust gases from the gas turbine, as well as the heat losses in the hot-gas heat exchanger, waste heat boiler and heating condenser. The results are presented graphically and are compared with the corresponding equation for the energetic total efficiency.