Day-ahead market price volatility analysis in deregulated electricity markets

The electricity market experiences pronounced short term volatility due to its peculiarities, first of all continuous load variations associated to the impossibility to profitably store electric energy. Electricity price forecasting is extremely important for all market players and in particular for generating companies, that must manage their units, and the associated economic risk, in the short, medium and long term. In general, price volatility depends on a large number of parameters such as: fuel prices (often related to currency exchange rates), availability of generating units, hydro generation production, demand elasticity and variations, network congestion and management rules of any specific electricity market. This study provides an analysis of day-ahead spot market price volatility in Spain, California, UK and PJM markets. Electricity prices for the years 1999 and 2000 have been used for the study. The analysis has been carried out on the basis of an original definition of price volatility.