Exergy and Electrical Rates for Distributed Power Systems

Abstract

Integrated resource planning provides a means for planning from both the demand and the supply sides. Exergetic analysis is derived from the Second Principle of Thermodynamics and accounts for not only the quantity of energy but for the quality of the energy involved. It is important that energy systems be designed so that the quality of energy of a given end-use is matched, as possible, with the natural resource, avoiding situations where high quality energy is used by an end-use that requires low quality energy. In the development of electric energy rate structures, different parameters are considered, such as social, political, strategic and engineering factors. Among the engineering factors, system efficiency is one of the most important. However, rational utilization of energy for lighting, heating and mechanical systems, for example, may or may not be encouraged by rate structures containing an efficiency component. System efficiency can be determined by both energetic and exergetic analysis. In energetic analysis, efficiency is just based on the energy flow through a system; where quality of energy is considered in exergetic analysis. So far, exergetic efficiency has not been considered in the development of electric energy rates. However, if exergetic considerations were used, this policy would have an important effect on the energy system. This article deals with the evaluation of the consequences of exergetic electric rate structures on society, agricultural customers and electric utilities. In particular, a case study of a distributed generation system will be used to demonstrate the application of exergetic analysis.