دیدگاه تعادل عمومی از اثرات ریباند جهانی

How do energy efficiency gains affect energy consumption? The effects are generally called “rebound effects” in the literature. Previous studies have extensively focused on only part of the global economy to study rebound effects, e.g. energy consumption by households, one industry, or one country. However, since the global economy is highly connected among countries, these studies may lead to misleading conclusions if the rebound effects in the rest of the economy are significant. Recently Saunders (2008) analyzes the demand side by taking the global economy as a whole. Wei (2007) also provides a general analysis by using Cobb–Douglas production functions for the global economy. The present article expands Wei (2007) general analysis to explore the rebound effects from an economist's viewpoint by taking the global economy as a whole and applying general forms of production functions. The analysis provides new insights related to rebound effects: we highlight the role of energy supply as a determinant of rebound. We show that the substitution between energy resources and other productive resources is more relevant to long term rebound. We predict that long term rebound may be lower than short term rebound. And we also discover that super-conservation can happen in both the short term and the long term.

How do energy efficiency gains affect energy consumption? As put forward very early by Jevons (1865), energy efficiency gains may not reduce energy consumption, but on the contrary, increase energy consumption. The effects are generally called “rebound effects” in the literature. Previous studies have extensively focused on only part of the global economy to study rebound effects, e.g. energy consumption by households, industries, or one country. However, since the global economy is highly connected among countries, these studies (e.g. Jalas, 2002, Gardner and Joutz, 1996, Glosmsrod and Wei, 2005 and Allan et al., 2007) may lead to misleading conclusions if the rebound effects are significant in the rest of the global economy, particularly in the long term. To provide insights of the rebound effects from a global perspective, this article develops a theoretical framework where the global economy is thought of as one entity. In the framework, we do not specify the forms of production and other functions, which allow us to explore any possible values of the rebound effects. In addition, energy input to the global economy is defined as energy resources in the nature. Typical examples are unextracted or underground fossil fuels. By doing so, we simplify the analysis and highlight the key role of energy resources. This is different from previous theoretical studies (e.g. Saunders, 2008 and Wei, 2007), where energy can come from a production process, e.g. extracted fossil fuels. The main insights offered in this article are as follows: • The supply side of the energy market is of equivalent importance to the demand side in quantitatively determining rebound. Most previous studies do not pay sufficient attention to the supply side. • The substitution between energy and other factors is more relevant to long term rebound, but less relevant for short term rebound since other inputs are not easy to adjust. • The theory claims super-conservation (i.e. the case that energy use is decreasing at a greater rate than an energy efficiency gain) can happen in both the short term and the long term. In the short term, super-conservation requires introducing externalities, while in the long term, it can happen without externalities, at least from the theoretical perspective. • The theory does not automatically predict higher long-run rebound than short-run rebound. This result can be used to explain the empirical findings by Allan et al., 2007 and Turner, 2009. The present article is organized as follows. The next section explains the basic concepts of rebound effects used in this article. This is followed by Section 3, which motivates the article. Section 4 introduces a general equilibrium model for the global economy. Section 5 contains the insights from the analysis deriving from the general model. Section 6 provides cautions and limitations related to the analysis. The last section concludes the article. Five appendices give a detailed description of the model and the in-depth analysis of short term and long term rebound effects.

By the application of a general equilibrium model to the global economy with a completely general form of the production function, this article has examined rebound effects in the global context and has drawn several insights. These insights may serve to assist the intuitive understanding of results generated from empirical studies. First insight highlights the importance of supply side of energy market. The majority of energy resources in the economy are unextracted fossil fuels. The finite stocks of fossil fuels may restrict the potential rebound effects displayed by studies focusing only on the demand side of the market. An extreme example would be that if the energy supply is fixed, the rebound effects must be zero no matter what the rebound is estimated from micro/macro-level. Second insight tells the relative importance of substitution between energy and other productive resources. We would expect more substitution could happen in long term than in short term. This implies that the substitution has relatively limited impacts on short term rebound. The third insight is probably the most interesting one. The theory claims that super-conservation, i.e. energy use is decreasing at a greater rate than an energy efficiency gain, can be one possible output of energy efficiency gains in both short term and long term. If this really happens, the policy to improve energy efficiency should be recommended. This has been discussed in several previous studies (e.g. Saunders, 2008 and Turner, 2009). The last insight tells long-run rebound can be less than short-run rebound. This theoretical result can be used to explain the empirical findings by Allan et al., 2007 and Turner, 2009. Further studies are expected. The model used for the analysis is highly simplified and far from the reality. It would produce more valuable results to guide energy policy making by relaxing some assumptions in the theory. For example, a capital efficiency gain can be included in the analysis. Empirical studies are also necessary to support the theory.