The effect of age on heat rate in central station power plants

It has been well established that as power plants age their performance, in terms of efficiency or heat rate, declines. For a number of reasons, power plants have been kept in operation for longer and longer periods, such that many operating plants are now beyond their original design retirement age. In addition, recent changes in the electric power industry as it moves toward a competitive environment via deregulation have made a study of the effect of age on equipment performance even more critical. This study analyzes a typical power plant cycle and determines which components have the most significant impact on overall performance from both a First and Second Law of Thermodynamics viewpoint. Historical data from operating plants is used to estimate performance curves of key equipment as a function of time. Finally, a method is suggested that incorporates these results and allows a determination of the "do nothing" alternative, which should allow better economic decisions concerning equipment repair or replacement. This should result in improved operating performance.