An Empirical Examination of Deregulated Electricity Prices

In this paper, we present an empirical analysis of deregulated electricity prices. We begin by examining the distributional and temporal properties of the price process in a non-parametric framework. This analysis is followed by comparing the forecasting ability of several different statistical models. The findings reveal several characteristics unique to electricity prices, including deterministic components of the series at different frequencies and a high degree of persistence in the price level. An “inverse leverage effect” is also found, where positive shocks to the price series result in larger increases in volatility than negative shocks. Results consistent with other asset prices, such as time-varying volatility are also uncovered. We find that existing financial models of asset prices fail to forecast the extremely erratic nature of electricity prices. Non-Markovian specifications, in conjunction with exogenous information (e.g. weather), are a necessary starting point for practical applications, such as security pricing. ∗This paper has benefited from conversations with Ravi Bansal, John Graham, Pete Kyle and Tom Rothenberg, and comments from Mike Lemmon. Knittel is from the School of Management at Boston University. Roberts is from the Fuqua School of Business at Duke University. Correspondence may be sent to Christopher Knittel at [email protected].