Decomposition of manufacturing energy-use in IEA countries: How do recent developments compare with historical long-term trends?

This paper examines manufacturing energy use due in 10 IEA countries between 1973 and 1998. Changes in energy use are described through using Laspeyres indexes to enable the decomposition of energy use into changes in the overall output of manufacturing (i.e. value added), the structure of output (industrial mix), and the energy intensity of each sub-sector, and to consistently compare the results across countries. The results show that structural changes have reduced manufacturing energy-use in most countries, particularly the US and Japan. In a few countries, however, the manufacturing structure became more energy-intensive and thus drove up energy use over the study period. For the group of 10 IEA nations, the net effect of structural changes accounted for more than a third of the reduction in total manufacturing energy use per unit of output between 1973 and 1998. The rest of the reductions in this period can be explained by falling energy-intensities in individual manufacturing branches. Contrasting post-1986 with earlier years shows that the rate of energy-intensity decline in manufacturing has slowed in most countries. Between 1994 and 1998 most countries experienced a strong growth in manufacturing output and a reduction in aggregated manufacturing energy use per unit output. However, the results of the decomposition analysis presented in this paper point to this reduction being mostly due to a structural shift towards less energy-intensive branches, such as electronics and electronic equipment, and that the impact from reduced energy-intensities was close to nil for the group of 10 IEA countries studied here.