Energy productivity improvements and the rebound effect: An overview of the state of knowledge

The 'rebound effect' from more efficient use of energy has been well investigated, with plenty of evidence suggesting that the 'direct' rebound effect is relatively small for most energy services-typically less than 30%. However, the same conclusion may not apply to 'indirect' and 'economy-wide' rebound effects. Here, several authors suggest that improved energy efficiency may increase energy consumption in the medium to long term, a view that undermines the rationale for energy efficiency as an instrument of climate-related energy policy and has been ardently debated. One of the main reasons behind the debate is the lack of a rigorous theoretical framework that can describe the mechanisms and consequences of the rebound effect at the macro-economic level. Proponents of the rebound effect point to 'suggestive' evidence from a variety of areas including economic history, econometric measurements of productivity and macroeconomic modelling. This evidence base is relatively small, highly technical, lacks transparency, rests upon contested theoretical assumptions and is inconclusive. This paper provides an accessible summary of the state of knowledge on this issue and shows how separate areas of research can provide relevant insights: namely neoclassical models of economic growth, computable general equilibrium (CGE) modelling and alternative models for policy evaluation. The paper provides a synopsis of how each approach may be used to explain, model and estimate the macro-economic rebound effect, criticisms that have been suggested against each, and explanations for diversity in quantitative estimates. Conclusions suggest that the importance of the macro-economic rebound effect should not be underestimated. (C) 2007 Elsevier Ltd. All rights reserved.