A method of studying power costs with reference to the load curve and overload economies

A great many curves have been presented before the Institute showing the relation between load factor and the cost of power. Some of them were based on very simple relationships between the elements entering into the total cost, and others have been of a purely empirical nature based on actual results. The interrelation of the various items of power cost is necessarily very complicated and dependent to a large measure on the skill and judgment of the engineer in charge. Few plants have been operated at any considerable range of load factor under the same operating engineer. It has been the privilege of the author to work up many of the curves presented to this Institute and he has been led to the belief that a more extended study of the subject is necessary in order to find the means of properly comparing the costs of power in different plants operating under different management, load conditions, coal costs, labor costs, and other circumstances.