Combined Cycle Configuration

In the combined cycle configuration, as its name depicts, describes the combination of gas turbine generators and steam turbine generators. Hence, the combined cycle configuration can be seen as the coupling of a gas turbine and a steam turbine through a HRSG, where the overall efficiency can be greatly improved by linking these two different thermal cycles together.

These CCPs generate electricity in two separate cycles:

1. In the initial cycle, natural gas and compressed air from a combustion turbine are blended and burned in a combustion chamber. The energy released during this combustion is used to turn a turbine, which in turn drives a generator to produce electricity. Exhaust gases are captured from the combustion turbines and are routed through a HRSG. This recovered heat, which would otherwise be wasted, is then used to convert water into steam.
2. In the second cycle, the steam generated from the HRSG is used in a steam turbine. The HRSG generates steam at several pressures as required by the steam turbine in order to make the most advantageous use of the energy available. Electricity is then made from an electric generator, which is driven by this steam turbine.

Thus, electricity is generated in both cycles, making this technology very efficient when compared to most conventional alternatives. In addition, with these two cycles of operations, the CCPs were designed to operate in two different arrangements, namely the Single-shaft Arrangement and the Multi-shaft Arrangement.