مصرف انرژی و انرژی R&D در OECD: دیدگاه های قیمت نفت و رشد اقتصادی

We estimate the short-run and long-run elasticities of various types of energy consumption and energy R&D to changes in oil prices and income of the 20 OECD countries over the period of 1980–2010 using the Nerlove partial adjustment model (NPAM). We find negative income elasticity for coal consumption but positive income elasticity for oil and gas consumption suggesting the importance of economic growth in encouraging the usage of cleaner energy from coal to oil and gas. By introducing time dummies into the regressions, we show that climatic mitigation policies are able to promote the usage of cleaner energies. Through the dynamic linkages between energy consumption and energy R&D, we find that fossil fuel consumption promotes fossil fuel R&D and fossil fuel R&D in turn drives its own consumption. Renewable energy R&D which is more responsive to economic growth reduces fossil fuel consumption and hence fossil fuel R&D.

As one of the most important sources of energy, crude oil continues to occupy a key position in the heart of many economies. To macroeconomists, oil price changes are significant source of economic fluctuations that affect many economies simultaneously. Oil price shocks have indeed occurred several times since World War II. For instance, the 1973–1974 oil price shock triggered by the Yom Kippur war and the 1979–1980 oil price shock as a result of Iranian revolution are the primary explanation of the stagflation of the 1970s. Interestingly, since the late 1990s, the global economy has experienced similar magnitude of oil shocks, but its impacts on output and inflation are relatively stable to many industrialized economies. To energy economists, oil price shocks should provide incentive to many economies, especially those without oil reserves, to use oil more efficiently either through more cautious oil consumption or the development of new technology that uses alternative sources of energy. While oil price shocks encourage more efficient use of oil and promote substitution away from oil to other alternative energy resources, economic growth during economic boom stimulates oil consumption. In light of this contradiction and its crucial policy relevance, this study is motivated to investigate how various types of energy consumption, including renewable energy, respond to oil price changes and income changes. As oil holds a prominent position as the principal of energy source, accounting for 36.3% of OECD primary energy consumption in 2010, much interest has been devoted to investigate the responses of oil consumption towards changes in oil prices and real output. Most recent studies include Ramanathan (1999), Cooper (2003), Ramanathan and Subramanian (2003), Narayan and Wong (2009) and Wadud et al. (2009). Cooper (2003) and Narayan and Wong (2009) find relatively inelastic oil consumption to changes in oil prices. Goodwin et al. (2004) show that elasticity of oil consumption to changes in oil prices ranges from 0.25 in the short-run to 0.64 in the long-run. As for the responsiveness of oil consumption to the changes in real output, Narayan and Wong (2009) document that oil consumption is more responsive, in terms of both magnitude and statistical significance in Australia. Narayan and Smyth (2007), however, document that the same coefficient is statistically insignificant in the Middle East. On the contrary, Wadud et al. (2009) show no meaningful relationship in the long-run between oil consumption, oil prices and real output before introducing the structural break during the oil shock. A new strand of recent literature has moved on to examine the elasticity of oil consumption using disaggregated data such as various gasoline products (see Huntington, 2010, Iwayemi et al., 2010 and Ramberg and Parsons, 2012). Own price elasticity of natural gas is also quite well-studied (see Cornillie and Fankhauser, 2004 and Erdogdu, 2010). As the existing studies tend to focus only on the own price elasticities of oil consumption and gas consumption, findings from these studies though useful could not be used to address the issue of how other forms of energy can be used as substitutes to oil. This study attempts to fill such a gap. This study is interested in finding out not only how countries change their energy consumption and energy R&D behavior during periods of soaring oil prices and income growth but also the dynamic linkage between energy consumption and energy R&D. While past studies did not seem to clearly distinguish the difference between energy consumption and energy R&D, they are indeed distinct and should be treated differently as energy consumption reflects the economy's demand for energy while energy R&D reflects the economy's supply of energy. Potential influence from one to the other could also arise. As a result, to differentiate the two, this study examines distinctly two different sets of relationships: (1) the impact of energy R&D, economic growth, oil and gas prices on energy consumption and (2) the impact of energy consumption, economic growth, oil and gas prices on energy R&D. Nerlove partial adjustment model (NPAM) is used to study the responses of various forms of energy consumption and energy R&D (including renewable energy consumption and R&D) to changes in oil prices and real output, using data from 20 OECD countries for the period 1980–2010. The purpose of this study is to assess the reliance of countries on oil and the potential to substitute away from oil to other energy sources. Similar studies which seek to determine the effects of oil consumption to the changes in oil prices or changes in income usually use either the NPAM method (e.g. Cooper, 2003) or the error-correction model (e.g. Wadud et al., 2009). Prior to the estimations of energy consumption or energy R&D to changes in oil prices and real output, this study conducts a two-stage-least-squares (2SLS) regression first to prevent the potential presence of endogeneity in the estimations. Time dummies are also included in the regressions to account for potential structural breaks. This study adds to the current literature in three dimensions. First, we examine not only the own price and income elasticities of oil consumption but also the responsiveness of other forms of energy consumption and energy R&D to the changes in oil prices and real output where energy consumption portrays energy demand, energy R&D portrays energy supply. Second, instead of examining solely the effects of oil price and income on energy, we include other variables such as the various energy consumption and accumulated energy R&D to reduce the problem of omitted variable bias. Third, we also clearly distinguish the responses of energy consumption and energy R&D to changes in oil prices and real output in two different groups of countries, with oil reserves and without oil reserves. Using group-country panel regressions, we analyze whether differences in oil endowments could potentially influence the willingness of countries to switch from one form of energy to another. Existing studies such as Wadud et al. (2009), Eltony and Al-Mutairi (1995), Cheung and Thomson (2004), and Narayan and Wong (2009) look at individual countries instead of groups of countries. The countries examined are the US, Kuwait, China, and Australia. There are several main findings in this study. First, growth in real output per labor plays a key role in promoting the usage of cleaner forms of energy. While negative income elasticity is found in coal consumption, positive income elasticities are found in oil, gas and renewable energy consumption. This finding suggests the importance of economic growth in promoting the usage of cleaner forms of energy from coal consumption to oil, gas, and renewable energy consumption. The regression results also show countries adopting more renewable energy technologies with economic growth. Second, economic growth has both direct and indirect effects on fossil fuel consumption. The direct effect suggests that higher economic growth leads to higher fossil fuel consumption. The indirect effect of higher economic growth on fossil fuel consumption works through renewable energy R&D. Higher economic growth promotes renewable energy R&D and renewable energy R&D in turn reduces fossil fuel consumption as renewable energy R&D has negative and significant effect on fossil fuel consumption The remaining of the paper is organized as follows. Section 2 outlines the empirical framework that is used in the estimation of elasticities of energy consumption and energy R&D to changes in oil prices and income in the 20 OECD countries. It explains the importance of oil price, gas price, and energy consumption or energy R&D in the regressions. Section 3 describes the data and methodology used in this paper. Tests for endogeneity and selection of structural breaks are also discussed. Section 4 discusses the empirical findings of the elasticities of energy consumption and energy R&D to changes in oil price and income. Section 5 concludes.

We have estimated both the short-run and the long-run elasticities of various energy consumption and energy R&D to changes in oil prices and income of the OECD countries over the period of 1980–2010 using the Nerlove partial adjustment model. As countries with different oil endowments may respond differently to changes in oil prices and income, three separate panel regressions are conducted for all the 20 OECD countries, OECD countries with and without oil reserves. A basic model, oil prices and income as the two key variables, is first estimated. An extended model is then used as a robustness check. Other variables including gas price to account for cross-price elasticity and fossil fuel R&D and renewable R&D to account for technological innovations are added into the extended model. Time dummies are also added to detect potential structural changes. There are a few interesting findings which are particularly worth noting. First, the results from this study show negative income elasticity of coal consumption but positive and significant income elasticities for oil and gas. This finding implies that economic growth is the key factor that drives countries to shift to the usage of a cleaner form of energy. Second, the time dummies also suggest that climatic mitigation policies, in general, are able to stimulate the use of cleaner energies. Third, in contrast to the finding of Narayan and Wong (2009) who find no significant statistical impact of changes in oil prices on oil consumption, our results show that when oil prices are higher, oil consumption is lower. This is not only true for all the three panel regressions (all OECD countries and OECD countries with and without oil reserves) but is also robust as the sign remains negative and significant as reported in the extended model. Fourth, significant and dynamic linkages are found between energy consumption, energy R&D and economic growth. Fossil fuel consumption promotes fossil fuel R&D and fossil fuel R&D in turn drives its own consumption. More importantly, economic growth is found to have both direct and indirect effects on fossil fuel consumption. While the direct effect suggests that higher economic growth leads to higher fossil fuel consumption, the indirect effect of higher economic growth on fossil fuel consumption works through renewable energy R&D. Higher economic growth promotes renewable energy R&D and renewable energy R&D in turn reduces fossil fuel consumption as renewable energy R&D has negative and significant effect on fossil fuel consumption. All these findings put together draw important policy implications. Policies that aim at increasing environmental awareness are less effective compared to policies that focus directly on reducing fossil fuel R&D and promoting renewable energy R&D. The dynamic linkages between energy consumption, energy R&D and economic growth established in this study suggest that fossil fuel consumption which usually leads to higher carbon emission can be reduced through lower fossil fuel R&D and higher renewable energy R&D. As a result, taxes on fossil fuel consumption and subsidies directed from fossil fuel R&D towards renewable energy R&D deem useful to facilitate the shift towards renewable energy-based economies.