Modular Repowering of Power Plants With Nominal Ratings Lower Than 180 MW: A Rational Design Approach and Its Application to the Italian Utility System

Abstract

The paper describes the rationale, the technical/economical details and the results of a study which is part of a large-scale energy conservation program enacted by the Italian Public Utility (ENEL), within a broader framework of structural interventions on the national electricity production/transportation/utilization network. The objective of the larger, long-term plan is to increase by a significant percentage (>5 percent) the net conversion efficiency of the national system. The purpose of the present study is to “recover” a large number of nearly obsolete steam power plants by converting them to a combined cycle configuration. The expression “generalized repowering” has been used to synthetically describe this plant reconfiguration plan, and will be employed in this paper. After giving a brief description of the existing Italian electricity generation situation, we list some possible criteria for repowering and describe in detail the configurations which were considered to be feasible. Finally, the proposed options are comparatively analyzed, and the major parameters which can be of importance in the actual decision-making process on the part of the Public Utility are computed and presented in tabular form. In the conclusions we try to put the present work in the broader perspective of a largescale (supernational), economically sound and ecologically acceptable energy conservation program.