Eight methods for decomposing the aggregate energy-intensity of industry

Since the early 1980s, the decomposition technique has been widely used in industrial energy analysis and for energy-policy evaluation. We describe eight different methods for decomposing the aggregate energy intensity of industry into the impacts associated with changes in industrial production structure and sectoral energy intensity. These eight methods, derived from economic index numbers, include two methods that are often used by researchers and three methods that are proposed for the first time. We show the linkages between index numbers and decomposition methods, which would assist analysts in method selection when undertaking decomposition studies. A simple example is presented to illustrate the characteristics of the eight methods.