Fallacies of energy efficiency indicators: Recognizing the complexity of the metabolic pattern of the economy

The strategy of energy efficiency to save energy is deceptively simple: the idea is to use less input for the highest amount of useful output. However, on a practical and conceptual level, efficiency is an ambiguous and problematic concept to implement. Of particular concern is the lack of contextual and qualitative information provided in energy efficiency measurements based on simple ratios. Oversimplification of efficiency measurements can have a detrimental effect on the choice of energy policies. Efficiency measurements are particularly problematic on a macroeconomic scale where a significant amount of meaningful information is lost through the aggregation of data into a simple ratio (economic energy intensity). First, practical examples are presented flagging conceptual problems with energy efficiency indicators, then an alternative accounting method—the end-use matrix—based on the concept of the metabolic pattern of social-ecological systems is illustrated to show the possibility of enriching efficiency indicators by adding qualitative and contextual information across multiple scales and dimensions. This method unpacks and structures salient energy input and output information in a meaningful and transparent way by generating a rich multi-level and multi-dimensional information space.The authors gratefully acknowledge funding from the European Union's Horizon 2020 research and innovation programme under grant agreements No. 649342 (EUFORIE) (MG and RVF) and No. 689669 (MAGIC) (MG, RVF and TD). RVF also acknowledges funding received from the Ministerio de Educación, Cultura y Deporte (MECD) of Spain (FPU12/05711). The Institute of Environmental Science and Technology (ICTA) has received financial support from the Spanish Ministry of Science, Innovation and Universities through the "María de Maeztu" program for Units of Excellence (MDM-2015-0552). This work reflects only the authors' view; the funding agencies are not responsible for any use that may be made of the information it contains