مصرف انرژی و رشد اقتصادی در نیوزیلند: نتایج مدل های سه متغیره و چند متغیره

This study examines the energy consumption–growth nexus in New Zealand. Causal linkages between energy and macroeconomic variables are investigated using trivariate demand-side and multivariate production models. Long run and short run relationships are estimated for the period 1960–2004. The estimated results of demand model reveal a long run relationship between energy consumption, real GDP and energy prices. The short run results indicate that real GDP Granger-causes energy consumption without feedback, consistent with the proposition that energy demand is a derived demand. Energy prices are found to be significant for energy consumption outcomes. Production model results indicate a long run relationship between real GDP, energy consumption and employment. The Granger-causality is found from real GDP to energy consumption, providing additional evidence to support the neoclassical proposition that energy consumption in New Zealand is fundamentally driven by economic activities. Inclusion of capital in the multivariate production model shows short run causality from capital to energy consumption. Also, changes in real GDP and employment have significant predictive power for changes in real capital.

The relationship between energy consumption and economic growth has received much attention in the recent economics literature. Economic theory is ambiguous regarding the direction of causality between these variables, as contrasting theoretical considerations suggest that energy consumption precedes economic growth and vice versa. Ecological economic theory asserts that energy resources are critical factors of production, such that energy consumption drives economic growth. Studies by Georgescu-Roegen (1975), Stern (1993), and Cleveland et al. (2000) raise questions about the theoretical feasibility of sustained economic growth given physical resource constraints, and the efficiency and equity implications of such growth. On the other hand, the growth models of the neoclassical school of thought imply that energy demand is a derived demand, so that energy consumption is a result of macroeconomic conditions (Lermit and Jollands, 2001). Central arguments of the proponents of neoclassical theory emphasise the role for substitution possibilities and technological progress to ameliorate resource scarcity and facilitate sustained growth in the presence of diminishing energy resources (see Stiglitz, 1974; Solow 1974; Dasgupta and Heal, 1974). The causal relationship between energy consumption and economic growth has remained empirically elusive and controversial (Masih and Masih, 1996). Country-specific studies on the relationship between energy consumption and economic growth outcomes can provide valuable policy insights, as energy conservation policies may be more difficult to enact. This is particularly so where energy consumption causes economic growth rather than in a situation where economic growth causes energy consumption, or no causal relationship exists between these variables. Furthermore, the nature of the underlying relationship may differ according to countries' economic structures. This study examines the energy consumption–economic growth nexus for the case of New Zealand, utilising cointegration and causality methodologies to estimate specific relationships between these variables. Several models are used to test the competing hypotheses based on distinct demand-side and production-side relationships between energy and output. The energy-growth literature is highly relevant for New Zealand given the current development of policy that seeks to balance national and international environmental imperatives with economic transformation objectives (Minister for Economic Development, 2006). Fatai et al. (2004) considered a bivariate relationship between energy resources and economic growth in New Zealand; however this study extends the analysis based on demand- and production trivariate and multivariate considerations. Trivariate and multivariate models incorporate other variables to ensure robust results that may alter the statistical relationship established in a bivariate framework. It also reflects on the policy implications suggested in the previous study to the findings of this paper. The remainder of the paper is structured as follows: Section 2 reviews economic theory and empirical evidence on the energy consumption–economic growth relationship for various countries. Data, methodology and models are discussed in Section 3 followed by the estimated results in Section 4. These include unit root tests, bounds test of cointegration, and Wald F-tests of short run Granger-causality. Identifying the nature of key relationships between the variables in the alternative model specifications provide some implications that are relevant to the current policy context of emissions trading and sustainability on the one hand, and economic transformation on the other. The final section presents the conclusions.

This paper presents the empirical findings of cointegration and causality between energy consumption and real GDP in the case of New Zealand. Trivariate demand and multivariate supply models address the potential bias of omitting key variables by including measures for energy prices, labour and capital. Results of the trivariate demand model indicate a single long run relationship between the three variables, revealing long run causality when energy consumption is the dependent variable. There is evidence of short run Granger-causality from real GDP to total energy consumption, providing support that economic growth causes demand for energy. The results of the trivariate production model identify a single long run relationship and short run Granger-causality from real GDP Granger to total energy consumption. This finding provides additional evidence in support of the proposition that energy consumption is a result of economic activity, rather than being an essential input to production per se. Granger-causality from employment to total energy consumption is also established, suggesting that a relationship exists between labour and energy factors of production. Further examination of the estimated long run relationship implies substitutability between these variables. The estimated multivariate production results for the bounds tests indicate the existence of one cointegrating relationship when real capital is the dependent variable. The Granger-causality test statistics indicate short run causality from real GDP to TCE but not vice versa, as well as significant short run causality from real capital and total energy consumption. The second major finding that capital and labour variables are important elements of cointegration and causality implies that the breadth of policy options may not be limited to energy and macroeconomic instruments. The key result, that real GDP Granger-causes energy consumption without feedback, is robust to the choice of modelling framework, which implies that economic and environmental policy objectives may be simultaneously achievable, and that the breadth of policy options may not be limited to energy instruments. Also, policy makers can be aware of improvements in economic growth forecasts when energy variable is in their models.