ارزش افزوده از طریق تجزیه و تحلیل تعادل عمومی از افزایش بهره وری در مصرف انرژی خانگی

This paper investigates the economic impact of a 5% improvement in the UK household energy efficiency, focussing specifically on total energy rebound effects. The impact is measured through simulations using models that have increasing degrees of endogeneity but are calibrated on a common data set, moving from a basic partial equilibrium approach to a fully specified general equilibrium treatment. The size of the rebound effect is shown to depend on changes in household income, aggregate economic activity and relative prices that can only be captured through a general equilibrium model.

There has been extensive investigation of the economy-wide rebound effects resulting from energy efficiency improvements in production. This analysis often uses a computable general equilibrium (CGE) modelling approach (see Dimitropoulos, 2007, Sorrell, 2007 and Turner, 2013 for a review). However, very few studies have attempted to measure the economy-wide impacts of energy efficiency improvements in the household sector. Following the work of Khazzoom, 1980 and Khazzoom, 1987 there have been a number of partial equilibrium studies (Dubin et al., 1986, Frondel et al., 2008, Greene et al., 1999, Klein, 1985, Klein, 1987, Nadel, 1993, Schwartz and Taylor, 1995 and West, 2004). Further, Greening et al. (2000) give a detailed and extensive summary of the extent of rebound on household consumption of different types of energy services. These studies assume that there are no changes in prices or nominal incomes following the efficiency improvement, and that the impacts are limited to the direct market for household energy use. This approach gives an extreme partial equilibrium figure, which is generally known as the direct rebound effect. To our knowledge, Dufournaud et al. (1994) is the only study that investigates full general equilibrium economy-wide rebound effects from increased energy efficiency in the household sector. It examines the impacts of increasing efficiency in domestic wood stoves in Sudan. Druckman et al. (2011), Freire-Gonzalez (2011) and Thomas and Azevedo, 2013a and Thomas and Azevedo, 2013b use a fixed price input–output model to consider indirect rebound effects resulting from household income freed up by energy efficiency improvements and spent on non-energy commodities. This work includes changes in energy use in production, as well as household consumption. However, we still treat this as a partial equilibrium approach as it fails to incorporate endogenous prices, incomes or factor supply effects. The aim of the present paper is to identify the added value from using general equilibrium techniques to consider the economy-wide impacts of increased efficiency in household energy use. We take as an illustrative case the effect of a 5% improvement in the UK household energy efficiency. The subsequent impact on energy use is measured through simulations employing models that have increasing degrees of endogeneity but are all calibrated on a common data set. That is to say, we calculate rebound effects for models that progress from the most basic partial equilibrium approach to a fully specified general equilibrium treatment.

The main contribution of this paper is to investigate the impact of efficiency improvement in the use of energy in household consumption and show the resulting partial and general equilibrium household and total energy rebound values. The results, summarised in Table 3 and Table 6, serve both a practical and conceptual purpose. They indicate the range of rebound values that can be derived from a given basic data set, depending on the precise way that the rebound measure is specified. However, these results also show how the rebound values can be deconstructed to reveal the relative size of the various effects. Let us begin with partial equilibrium. First, note that the value of the elasticity of substitution between energy and non-energy commodities in household consumption is important in determining the size of this effect. This finding reflects observations made in the case of increased efficiency in productive energy use by several authors (including Saunders, 1992, Sorrell, 2007 and Turner, 2009) but extends to the case of household energy efficiency. We find that the appropriate elasticity value depends not only on the time period under consideration but also whether the efficiency improvement is embedded in the design of household durable goods or not. Second, we strongly identify the negative impact on the rebound value when the focus shifts from household consumption to total energy consumption. This phenomenon reflects the relative energy intensity of energy production itself. This means that when direct household consumption of energy falls, indirect consumption of energy falls also, reducing the total rebound. Moreover, we demonstrate that this negative pressure on rebound is present in both partial and general equilibrium cases, though it may be partially offset through price effects in the latter. The substitution elasticity and intermediate input effects identified under partial equilibrium remain largely undiminished in the general equilibrium analysis. However, general equilibrium also incorporates the impact of changes in relative prices, incomes and economic activity. We observe that the main additional general equilibrium impacts occur in the short run where the fall in energy prices cushions the fall in energy use. This leads to the short-run general equilibrium rebound values being greater than both the corresponding partial equilibrium and long-run general equilibrium figures (for the same elasticity of substitution value). In the long run, capital adjustments severely reduce the relative price changes that occur in the short run, leaving the rebound values closer to their partial equilibrium counterparts. Finally, where further expansionary effects of the energy efficiency improvement are incorporated through a fall in the nominal wage, the positive additional rebound effect is relatively limited. Our findings have important implications for the consideration of policies aimed at increasing energy efficiency in the household sector. First, the nature of the general equilibrium response under these circumstances is quite different to that where efficiency improves in production. However, existing analyses by, for example, the IEA have focussed on the relationship between economy-wide rebound and productivity-led growth (Ryan and Campbell, 2012). We have shown here that the transmission mechanism that links energy efficiency improvements on the consumption side of the economy with energy use in the production side operates through changing derived demand and prices, with no change in productivity in production. Only where the efficiency improvement directly impacts wage demands does industry enjoy a reduction in factor input prices. The second key feature of interest to policy analysts is the need to understand the general equilibrium dynamics that put a range of upward and downward pressures on economy-wide rebound at different stages of the adjustment process. To date much of the policy (and academic) literature on the issue of rebound has focussed on the range of demand-side drivers of rebound with insufficient attention to the capacity and pricing decisions of energy suppliers when they are faced with changing demand for, and revenues from, their production.