Power capacity: A key element in sustainability assessment

Starting from the characterization commonly used in energy systems engineering, this paper seeks to clarify the concept of power capacity when used in sustainability assessment. It provides explicit methods of assessment for the different types of power capacity used by human societies. Power capacity refers to the converters transforming energy flows at a given time rate. Dealing with societal transitions therefore requires being able to characterize properly those converters in addition to the study of energy flows. However, this requires extending the timescale typically considered in conventional energy analysis which entails several epistemological problems over sustainability assessment.