Improved technical efficiency and exogenous factors in transportation demand for energy: An application of structural time series analysis to South Korean data

This paper stresses the importance of incorporating the effects of improved technical efficiency and exogenous factors when estimating energy demand functions. Using annual time series data for the period 1973–2007 in the STSM (structural time series model) developed by Harvey et al. [26] the paper estimates price and income elasticities of demand for energy as well as the annual growth of the stochastic trend at the end of the estimation period. The results of the study reveal a long-run income elasticity of 1.37 and a price elasticity of −0.19. In addition, the underlying trend is generally stochastic and negatively sloping during the greater part of the estimation period. Finally, the estimated result from the structural time series is compared with the results from the Johansen Cointegration. These results suggest that income is the dominant factor in energy consumption. In addition, the coefficient of linear trend is negative, supporting the results from the STSM.