In post cycle power generation steam turbine units using coal, oil, and other fuels, a small gas turbine is used as the auxiliary circulation system of the power plant to preheat and blast the boiler, improve combustion, improve efficiency, and directly use power to drive the feedwater pump. In 1947, the first industrial gas turbine in the United States was involved in the operation of the power generation cycle system using this method.

The circulating system composed of a gas turbine and a flue gas turbine further drives the flue gas turbine to generate electricity by utilizing the remaining pressure and enthalpy in the flue gas emitted by the gas turbine. Compared with the gas steam combined cycle system, this system does not require water at all, but the cost of the flue gas turbine is relatively high and has not yet been widely used.