Quantifying global exergy resources

Exergy is used as a common currency to assess and compare the reservoirs of theoretically extractable work we call energy resources. Resources consist of matter or energy with properties different from the predominant conditions in the environment. These differences can be classified as physical, chemical, or nuclear exergy. This paper identifies the primary exergy reservoirs that supply exergy to the biosphere and quantifies the intensive and extensive exergy of their derivative secondary reservoirs, or resources. The interconnecting accumulations and flows among these reservoirs are illustrated to show the path of exergy through the terrestrial system from input to its eventual natural or anthropogenic destruction. The results are intended to assist in evaluation of current resource utilization, help guide fundamental research to enable promising new energy technologies, and provide a basis for comparing the resource potential of future energy options that is independent of technology and cost.