A Method of Evaluating Life Cycle Costs of Industrial Gas Turbines
When aero-derivative gas turbines were first introduced into industrial service, the prime criterion for assessing the “relative value” of equipment was derived hy dividing the initial (or capital) cost of the equipment by the number of kilowatts produced. The use of “dollars per kilowatt” as an assessment parameter emanated from the utility sector and is still valid providing that the turbo-machinery units under consideration possess similar performance features with regard to thermal efficiency. Second generation gas turbines being produced today possess thermal efficiencies approximately forty-five percent greater than those previously available. Thus, a new criterion is required to provide the purchaser with a better “value” perspective to differentiate the various types of turbo-machinery under consideration. This paper presents a technique of combining the initial cost of equipment with the costs of fuel consumed, applied labor and parts to arrive at an assessment parameter capable of comparing the relative merits of varying types of turbo-machinery. For simplicity, this paper limits the life cycle cost derivation and discussion to turbo-generator units; however, the principles of this type of life cycle analysis can also be applied to gas turbines in mechanical drive applications and/or combined cycles.