Resource Accounting and Waste Impact: Limitations of Exergy as a Sustainability Tool

Exergy is a thermodynamic concept that has been widely promoted for assessing and improving sustainability, notably in the characterization of resources and wastes. Despite having notable benefits, exergy is often misused by authors who tend to apply it as an intrinsic characteristic of an object (i.e., as a static thermodynamic property). Using both theoretical and empirical evidence the authors introduce the challenges involved with applying exergy as an intrinsic characteristic matter with particular focus on resource value and waste impact. These challenges lead to an in-depth discussion of current major reference environment formulations and reveals that the properties of exergy reference environments are not reconcilable with the properties of the natural environment. The authors conclude by arguing that exergy practitioners should abandon attempts to formulate standard comprehensive reference environments and return to process dependent reference environments that exergy was originally based upon. In this regard, the authors are proposing that exergy be seen as a context- or environment-dependent decision-making tool and not as an intrinsic characteristic of matter.