Combined Cycle Plant

Applications

Large scale power production

Overview

The Combined Cycle power plant is a combination of a fuel-fired turbine with a Heat Recovery Steam Generator (HRSG) and a steam powered turbine. These plants are very large, typically rated in the hundreds of mega-watts.

Depending on the power requirements at the time, the combined cycle plant may operate only the fired turbine and divert the exhaust. However, this is a substantial loss of efficiency. Large fired turbines are in the low 30% eff. range, while combined cycle plants can exceed 60% efficiency.

Single Shaft Combined Cycle Plant

Multi-Shaft Combined Cycle Plant, steam turbine and generator are on the left side of the diagram.

Source: Siemens web site 8/01; TechPro DTE Energy Bob Fegan 2002