Dimensions of energy efficiency in a political context

Energy efficiency is widely accepted as a simple and cost-effective way to reduce energy consumption and greenhouse gas emissions. It is accordingly a corner stone of European energy and climate policies. However, in formulation of explicit political energy efficiency goals as well as in monitoring these targets, discussions arise both concerning the concrete definition and the measurement. Accordingly, there is a lack of clarification and in-depth discussions of several fundamental aspects or dimensions of measuring energy efficiency, in particular in a political context. Here, we discuss and analyse two aspects of energy efficiency and ways to measure it, namely the formulation of a baseline and the accounting methods, in order to clarify ongoing discussions. We find that both top-down and bottom-up methods contain a series of "adjustment settings" which can strongly influence the degree of energy efficiency target achievement. Additionally, several baselines can be meaningfully defined and used in a political context. We find a factor of 10 or more between different meaningful definitions of energy efficiency easily achievable. Our results indicate that rigorous definitions should be used for formulating and monitoring energy efficiency targets in a political context if exactly the same understanding of target is to be achieved.