Energy Efficiency : What Has it Delivered in the Last 40 Years?

This article presents a critical assessment of research over the last 40 years that may be brought under the umbrella of “energy efficiency,” spanning different aggregations and domains – from individual producing and consuming agents to economy-wide effects, the role of innovation, and the influence of policy. After 40 years of research, energy efficiency initiatives are generally perceived as being highly effective. Innovation has contributed to lowering energy technology costs and increasing energy productivity. Energy efficiency programs in many cases have reduced energy use per economic output and have been associated with net improvements in either welfare or emission reductions or both. Rebound effects at the macro level still warrant careful policy attention as they may be non-trivial. Complexity of energy efficiency dynamics calls for further methodological and empirical advances, multidisciplinary approaches, and granular data at the service level for research in this field to be of greatest societal benefit