Measuring and testing natural gas and electricity markets volatility : evidence from Alberta's deregulated markets

A number of innovative methods for modelling spot wholesale electricity prices have recently been developed. However, these models have primarily used a univariate time series approach to the analysis of electricity prices. This paper specified and estimated a multivariate GARCH-M model of natural gas and electricity price changes and their volatilities, using data over the deregulated period between January 1996 to November 2004 from Alberta's spot power and natural gas markets. The primary objective of the model was to investigate the relationship between electricity and natural gas prices. It was noted that the model allows for the possibilities of spillovers and asymmetries in the variance-covariance structure for natural gas and electricity price changes, and also for the separate examination of the effects of the volatility of anticipated and unanticipated changes in natural gas and electricity prices. Section 2 of the paper provided a description of the model used to test for causality between natural gas and electricity price changes, while section 3 discussed the data and presented the empirical results. It was concluded that there is a bidirectional causality between natural gas and electricity price changes. However, neither anticipated nor unanticipated natural gas price volatility causes electricity price changes. Anticipated electricity price volatility has a causal effect on natural gas. 10 refs., 2 tabs., 3 figs