قیمت نفت، مصرف انرژی هسته ای، و رشد اقتصادی: شواهد جدید با استفاده از تحلیل ناهمگن پانل

This paper applies panel data analysis to examine the short-run dynamics and long-run equilibrium relationships among nuclear energy consumption, oil prices, oil consumption, and economic growth for developed countries covering the period 1971–2006. The panel cointegration results show that in the long run, oil prices have a positive impact on nuclear energy consumption, suggesting the existence of the substitution relationship between nuclear energy and oil. The long-run elasticity of nuclear energy with respect to real income is approximately 0.89, and real income has a greater impact on nuclear energy than do oil prices in the long run. Furthermore, the panel causality results find evidence of unidirectional causality running from oil prices and economic growth to nuclear energy consumption in the long run, while there is no causality between nuclear energy consumption and economic growth in the short run.

Recently, many imported-energy-dependent countries in the world have experienced energy crises since the 1970s, a consequence of which oil prices increase rapidly and oil supply declines sharply, and have confronted global warming resulting from greenhouse gas (GHG) emissions. To combat these energy and environmental configurations, one of the important priorities of energy and environmental policies is to diversify the sources of energy and to find a secure, cheap and non-GHG-emitting energy supply (Fiore, 2006 and Vaillancourt et al., 2008; Wolde-Rufael, 2010). As noted by the International Energy Agency (IEA, 2008), nuclear energy may answer these conditions. Nuclear energy provides a long-run and high-performance option, and may contribute to environmental policies for global climate control as well as to energy security (Apergis et al., 2010).1 Besides, the development of nuclear energy can lead to the spill-over effect of industry-wide technology, and can promote the productivity of labor, capital and other factors of production (Frewer and Altvater, 1977 and Yoo and Jung, 2005). Thus, in order to consider future economic development and energy demands, the development of nuclear energy is expected to be a valid option in the globally sustainable development strategy (Duffey, 2005, Omoto, 2005 and Vaillancourt et al., 2008). The importance of nuclear energy as providing a major solution to energy security and global warming directs us to investigate the determinants of nuclear energy consumption and the nuclear energy–economic growth nexus. Some researchers recently have examined the causal relationship between nuclear energy consumption and economic growth. However, except for Apergis and Payne (2010a) and Apergis et al. (2010), most of them adopt the time-series data of nuclear energy consumption for each individual country, which is insufficient, and thus their empirical results may suffer from small sample bias. For the power of the traditional cointegration test (Johansen, 1988), multivariate systems with small sample sizes can be severely distorted. To this end, we need to combine information from time-series and cross-section data once again, and thus we use panel unit-root tests and heterogeneous panel cointegration tests, including heterogeneity in both the long-run relationships and the short-run dynamic adjustments.2 The contributions and objectives of this paper are as follows. First, this paper considers a multivariate model of nuclear energy consumption, real oil prices, oil consumption, and real income, which allows an additional channel of causality to be examined. In addition, we attempt to jointly analyze the energy-growth hypothesis and the effect of nexus between oil and nuclear energy.3 To differ from the existing literature on the nuclear energy–income nexus that does not take oil consumption and real oil prices into account, we can estimate the cross-price elasticity of nuclear energy with respect to oil, and then analyze whether a substitute or complementary relationship between nuclear energy and oil exists. Second, in this paper we test the long-run relationship among these variables employing the heterogeneous panel cointegration test developed by Pedroni (2004), which allows for cross-sectional interdependency among different individual effects. The elasticities of oil prices and real income for nuclear energy are estimated using the dynamic OLS (hereafter DOLS; Kao and Chiang, 2000) technique for heterogeneous cointegrated panels. Third, since the causal relationship between nuclear energy consumption and economic growth and that between oil prices and nuclear energy consumption may run in either or both directions – whether or not being transitory or permanent – the estimations of the vector error-correction model (VECM) which we use to test the statistical causality hypothesis are more reliable than those from a single equation model. We also apply a panel VECM to distinguish between short-run and long-run causalities. Fourth and finally, it is well-known that erroneously omitted breaks can cause a deceptive inference in time-series testing and the effects of structural breaks do not disappear simply because one uses panel data. The current research makes a valuable contribution to this line of research stemming from the fact that the phenomenon of structural breaks is a common problem in macroeconomic series, given that they are usually affected by exogenous shocks in environmental or economic events (Altinay and Karagol, 2004 and Rao and Kumar, 2009). The direction, strength, and stability of the relationship among nuclear energy, oil market activities, and real income play a pivotal role in the implementation of energy or environmental policies. The remainder of this study is organized as follows. Section 2 provides the brief literature review. Section 3 introduces the panel unit-root tests, panel cointegration techniques and the causality tests. Section 4 illustrates the definitions for the variables, data sources and provides the empirical result. A conclusion is provided in Section 5.

This paper employs a recent advance in panel data analysis to estimate the panel cointegration and panel vector error-correction models for a group of six developed countries using annual data covering the period 1971–2006. We investigate the interrelationship between nuclear energy consumption and economic growth using the multivariate model, controlling for the activities of the oil markets, and by exploring the dynamic directions of the causality among variables. The empirical results show that: first, we obtain solid and convincing evidence of a fairly strong long-run equilibrium relationship among them, thus we refute the neutrality hypothesis of nuclear energy–income that has previously been advanced. Second, the panel results indicate that a 1% increase in real oil increase contributes to nuclear energy consumption by 0.12%, meaning that a substitute relationship exists between nuclear energy and oil. Oil consumption and real income have a positive impact on nuclear energy consumption. In addition, the estimated income elasticity of nuclear energy is 0.89, which is close to unit elasticity in the long run. Third and finally, the panel causality test shows that in the short run, there is no causal relationship between real oil prices and nuclear energy consumption, between oil and nuclear energy consumption as well as between real income and nuclear energy consumption while evidence of unidirectional causality from oil prices, oil consumption and real income to nuclear energy consumption is found in the long run. Our empirical findings have major policy implications as follows. First, the substitute relationship between nuclear energy and oil suggests that in order to reduce the degree of dependence on oil imports and demand, the imported-energy-dependent countries should develop nuclear energy to cope with their demands for energy under the fluctuation of oil prices, the instability of oil supply, and global warming. Second, the results of the short-run and long-run causality tests imply that a short-run energy policy may not be beneficial to the development of nuclear energy. Countries should set up long-run income and energy policies for stimulating their nuclear energy development. Third, we find that a unidirectional causality running from real income to nuclear energy consumption exists in the long run. In this case, nuclear energy consumption is fundamentally driven by real income, and as such, taking measures to conserve energy may be feasible without compromising economic growth. Fourth, since there is no causality between nuclear energy consumption and economic growth in the short run, the implication is that energy conservation will not hurt economic growth and development in the short run. Hence, it is safe to assume that energy conservation is a feasible policy tool for these (investigated) developed countries. Fifth, to compare the results for each country, we can find that the increases in real oil prices and real income have a larger effect on nuclear energy consumption in Japan and the U.S.A. It implies that in the current upsurge of international crude oil, Japan and the U.S. can effectively reach the purpose of substituting nuclear energy consumption for oil consumption more. A policy implication emerges that in order to reach the current American President's New Energy policy of reducing 10 million barrels of oil consumption per day (approximately one-eighth of global daily oil consumption) by 2030, the U.S. government can develop nuclear energy to reduce its oil demand. Japan has few natural resources of its own and depends on imports for 80% of its primary energy needs. Thus, while the Japanese government tends to reduce its degree of dependence on oil imports, it should be devoted to nuclear energy development. Finally, from our results of structural break tests for each country, we find that the estimated structural breaks occur after three rounds of energy crises, implying that these energy crises have a significant impact on the nuclear energy–income nexus. Thus, countries that are energy-dependent should actively practice some energy policies, i.e. the oil reservation mechanism, the improvement of energy consumption efficiency and the development of substitute energy for oil, in order to reduce the negative shock of these (and any such future) energy crises on their economic growth.