A review of the use of exergy to evaluate the sustainability of fossil fuels and non-fuel mineral depletion

This paper reviews methods that measure mineral resource depletion based on cumulative exergy consumption approaches. It focuses on the exergy replacement cost (ERC), which measures the amount of exergy society would have to consume in order to re-concentrate an extracted and processed mineral to the point that it can be once more exploited by future generations. The ERC, which was originally only suitable for non-fuel minerals, was adapted and extended in 2016, by changing the focus of the ERC from the chemical composition of the resource to its function, to include fossil fuel depletion. This paper discusses the impact of these new developments and identifies conceptual and methodological weaknesses that need to be addressed for the ERC to find widespread use in exergy analysis and in order to assess the sustainability of mineral policy from the grave to the cradle.