Rehabilitation of thermal power plants

Fossil-fired power plants currently account for 65% of the world's electricity needs [B 1 250] . Most of these plants are more than 15 years old, and operate with much lower efficiencies than modern units designed for combined gas-steam cycles or conventional steam cycles with supercritical parameters. Improving the performance of these older plants is a must in the years to come.

In this context, the use of gas turbines for the rehabilitation of thermal power plants represents one of the best solutions. There are various ways of coupling a gas turbine with an existing steam cycle. Particular emphasis is placed on the technical aspects of the combined cycles that result from retrofitting. Each retrofit solution is illustrated with typical examples encountered in real-life applications. A case study of a 100 MW steam unit is used to compare the various retrofit solutions.