Thermal and Economic Measures of Energy Use: Differences and Implications

Statistical agencies often report aggregate energy use by expressing different energy types on a common basis with thermal conversion factors. Before the energy crisis of the 1970s Turvey and Nobay (1965) indicated some pitfalls associated with thermal conversion factors in the analysis of aggregate energy use. This point has been emphasized again by Berndt (1978). More recently Hong (1983) compared two Divisia indexes of energy useone of the expenditure shares and the other with thermal shares-and he found the two indexes behaved differently in the United States from 1950 to 1978. The relationship between the relative prices of energy types, which change over time, and their relative thermal contents, which are usually taken to be constant, explains why these two measures of energy use follow different paths.