Modeling the stylized facts of wholesale system marginal price (SMP) and the impacts of regulatory reforms on the Greek Electricity Market

This work presents the results of an empirical research with the target of modeling the stylized facts of the daily expost System Marginal Price (SMP) of the Greek wholesale electricity market, using data from January 2004 to December of 2011. SMP is considered here as the footprint of an underline stochastic and nonlinear process that bears all the information reflecting not only the effects of changes in endogenous or fundamental factors of the market but also the impacts of a series of regulatory reforms that have continuously changed the market's microstructure. To capture the dynamics of the conditional mean and volatility of SMP that generate the stylized facts(mean reversion, price spikes, fat tails price distribution etc), a number of ARMAX GARCH models have been estimated using as regressors an extensive set of fundamental factors in the Greek electricity market as well as dummy variables that mimic the history of Regulator's interventions. The findings show that changes in the microstructure of the market caused by the reforms have strongly affected the dynamic evolution of SMP and that the best found model captures adequately the stylized facts of the series that other electricity and financial markets share. The dynamics of the conditional volatility generated by the model can be extremely useful in the efforts that are under way towards market restructuring so the Greek market to be more compatible with the requirements of the European Target Model.