Load Duration Characteristics and Cogeneration Analysis

Abstract

This paper describes the importance of accurate calculation of thermal and electrical energy production by cogeneration plants on the overall validity of cogeneration projects. A new simple graphical method which improves the accuracy of calculation of annual thermal and electrical energy consumption and production by various energy sources is proposed. A practical example of developing annual load duration characteristic using the proposed method is provided. Several illustrative graphs are included. Evaluating the feasibility of an energy conservation project normally involves comparing of the saved operating cost with the additional capital costs required to implement the project. Operating costs, which can also be called running costs, include energy costs and equipment operating and maintenance costs. Normally, energy costs represent a major part of the running costs and, therefore, are the major factors affecting the overall profitability of the project. It almost goes without saying that an economic analysis of an energy conservation project is much more sensitive to the variations in the cost of energy than to changes in the capital costs. It is quite common that a 10 percent change in the energy cost can produce dramatic economic changes, while the same or a much larger change in the capital cost often has only a marginal effect on the economics.