The value of energy carriers

Abstract

The value of energy carriers can be described thermodynamically by the amount of heat (enthalpy method) or work (exergy or availability method) that can be obtained from the carriers. Prices for energy carriers are used in economics to express their values. The prices for energy carriers are often related to their enthalpies when other properties and conditions are equivalent. However, it has been suggested that the exergy of the energy carriers is the proper quantity to establish their values, i.e. prices should be based on these exergies.

In this paper, the structure of the energy demand is included in the analysis of the value concepts. The aggregated energy demands of the industries in The Netherlands and West Germany (F.R.G.) are used as examples. Optimization of the total system is the proper way to establish the performance of energy carriers. In this optimization, several assumptions must be made about availability and applicability of technical options, such as heat cascading, cogeneration and heat pumps. The structure of the demand influences the importance of energy carriers and thus their value in a given system. Neither the enthalpy nor the exergy of the energy carriers is an adequate base for price setting.