The Potential for Additional Energy Efficiency Savings Including How the Rebound Effect Could Affect This Potential

Abstract

Since the 1970s, efforts to improve energy efficiency and save energy have been undertaken by many countries, businesses, and individuals. Since 1980, energy efficiency has reduced US energy use by about 1.2 % per year, with savings even higher in some countries and a bit lower in other countries. Given this past history, this paper reviews a variety of studies that estimate how much energy efficiency potential remains, looking at studies that estimate efficiency potential out to at least 2030 and, in multiple cases, out to 2050. Based on these studies as well as past accomplishments, we find that compound energy efficiency savings of 1.0–1.4 % per year appear to be feasible, and savings of 2.0–2.6 % per year might be possible but have been infrequently demonstrated in practice. These estimates of potential future savings by and large do not include rebound effects, although estimates of past efficiency improvements do generally include rebound effects. We summarize studies that look at direct and indirect rebound effects. We find that direct and indirect rebound effects are generally each in the range of 10–20 % and therefore total rebound typically is in the 20–30 % range. We then reduce the estimates of future energy efficiency potential to account for this rebound and find that at a minimum it appears that recent rates of energy efficiency improvement can be sustained for many years. Some studies estimate that even higher rates of energy efficiency improvement can be achieved, but to do so would be entering largely uncharted territory.