Simple Cycle Configuration

The simple cycle power plant configuration is essentially the first stage of the combined cycle plant, without the heat recovery feature. In this configuration, it consists of a gas compressor, a fuel combustor, and a gas turbine.

The operating principle of the simple cycle plant is illustrated as follows:

1. Ambient air intake to be compressed in the gas compressor.
2. Energy is added to the compressed air by combusting the liquid or gaseous fuel in the combustion chamber.
3. Within the combustor, fuel is added and oxidized by the compressed air and oxygen to produce large amounts of energized products. This hot and compressed air is then expanded through a gas turbine, which drives both the compressor and an electric power generator. Energy that is released during the expansion in the gas turbine will then drive the gas turbine through the shaft.
4. The resulting flue or exhaust gas coming out from the gas turbine is usually discharged into the atmosphere.
5. This gas turbine is connected to a generator and by driving this generator; electricity is then produced.

Simple cycle power plants are usually used primarily to provide either "peaking" or standby service. The main advantage of the gas-fired simple cycle plant is its ability to start up quickly and to bring electricity on-line as needed. However, due to the absence of the heat recovery ability, this configuration is not commonly practiced in the industry as compared to the combined cycle configuraton.