Estimating Hourly Electric Load with Generalized Least Square Procedures

Although electricity demand receives much attention in the empirical literature (see Taylor (1975) and EPRI (1982b) for excellent surveys on the topic), hourly load demand analysis has only recently begun. Notable contributions are a series of studies sponsored by the Electric Power Research Institute (EPRI (1977. 1979a, 1979b, 1981a, 19816. 1982a) and Platt (1983)). These studies estimate load curve models for regions of the United States. Unfortunately, from a utility perspective, the empirical results presented in these studies are not directly applicable. Further, because the data used in these studies are not generally available at the geographic level of a utility service area, applying their methodology is problematic. This paper presents a practical method for an electric utility to produce an hourly load curve model similar in overall framework to these studies. Our procedure is innovative in that it produces statistically efficient estimates, which the above papers do not. We also demonstrate a method that uses supplementary forecasts to enhance the forecasting performance of the hourly load model.