شواهد تاریخی برای بازگشت بهره وری انرژی در 30 بخش ایالات متحده و ابزاری برای بازگشت تحلیلگران

This article presents a detailed econometric analysis of historical energy efficiency rebound magnitudes in the US economy by sector and in aggregate. The results strongly suggest that energy consumption forecasts that ignore rebound effects will systematically and significantly understate energy consumption. Accompanying this article is a toolkit that allows any analyst to conduct a comparable analysis for any country, or sector, for which the data are available

Energy consumption forecasts, especially those used to inform climate change mitigation policy, must explicitly account for projected technology improvements in energy use efficiency. While nearly all do, such projections often fail to take account of rebound effects, whereby energy consumption may not be reduced on a one-for-one basis with energy efficiency gains. For example, The Intergovernmental Panel on Climate Change (IPCC) of the United Nations projects that by 2030 energy efficiency gains will provide a substantial part of the remedy for climate change by reducing global energy consumption approximately 30% below where it would otherwise be—nearly sufficient to offset projected economic growth-driven energy consumption increases.12 Like the IPCC report, the widely-cited [58] report is seen by many as reflective of current best thinking on the question of future energy consumption trends. The Stern report, relying on projections made by the International Energy Agency (IEA), offered that the “technical potential for efficiency improvements to reduce emissions and costs is substantial,” and cited the IEA finding that “energy efficiency has the potential to be the biggest single source of emissions savings in the energy sector.”3 This conclusion is supported by several analyses that project comparable energy reduction benefits arising from deploying visible “below cost” energy efficiency technologies.4 However, these studies fail to take account of rebound effects, either altogether or (generously) in any significant way. This article quantitatively examines the consequences of ignoring such effects by analyzing empirical evidence for rebound found in the historical record for the US economy. The results indicate that so-called direct rebound magnitudes in the productive part of the US economy (about two-thirds of the energy economy, annual energy consumption-wise) were substantial over the period examined. The productive part of the economy is that portion involved in the creation and movement of goods and services—agriculture, industry, wholesale and retail commerce, commercial transport, finance, and government enterprises. Especially when taken alongside the potential for energy efficiency rebound arising from other “indirect” sources not considered here, the results provide a strong argument in favor of explicitly accounting for rebound effects in energy consumption forecasts. A key implication is that, to the extent conventional forecasts that provide a basis for climate change mitigation policy ignore or improperly treat rebound, there is less time than is commonly assumed to devise climate change solutions.

This analysis appears to offer significant motivation for including consideration of rebound effects in energy consumption forecasts. But it also lays down some technical challenges to the energy economics community. Perhaps most urgently, this article can be in part interpreted as an appeal to energy economists to include measured, flexible cost/production functions in their analyses of energy consumption trends and rebound magnitudes; and also an appeal to use measured technology gains for all factors of production. But the challenge is offered as something larger than this. While the analysis of this article is possibly the most thorough, methodical, systematic, and carefully done analysis of historical evidence for energy efficiency rebound to date, given the cautions and limitations cited above and the enormous stakes involved, it is greatly to be hoped by any serious student of the subject that this analysis is very soon superseded by a much better one. In the meantime, the toolkit offered here may provide a convenient means for attacking the measurement of rebound in various economies for comparison to the US economy, and, one hopes, a relatively reliable one.