Estimating Marginal Costs and Market Power in the Italian Electricity Auctions

In this paper we examine the bidding behaviour of firm competing in the Italian wholesale electricity market where generators submit hourly supply schedule to sell power. We describe the institutional characteristics of the Italian market and derive generators' equilibrium bidding functions. We also discuss the main empirical strategies followed by the recent econometrical literature to obtain estimates of (unobservable) optimal bids. Then, we use individual bid data, quantity volumes and other control variables to compare actual bidding behaviour to theoretical benchmarks of profit maximization. We obtain estimates of generators' costs to be used in conjunction with hourly market equilibrium prices to derive some measures of the extent of market power in the Italian electricity sector and of its exploitation by firms.Bidding behaviour in Electricity markets, Estimates of optimal bid functions, Measures of market power

Price capping in partially monopolistic electricity markets

In this paper we consider an oligopolistic market in which one firm can be monopolist on her residual demand function and derive implications on the shape of her profit function, which we show may not be concave in price. We propose a simple price-capping rule that induce the pivotal operator to compete for quantity instead of taking advantage of her monopoly. Then, we analyze the bidding behaviour of the dominant electricity producer oper- ating in the Italian wholesale power market (IPEX). This firm is vertically integrated and in many instances she acts as a monopolist on the residual demand. We find that, contrary to expectations, this pivotal firm refrains to exploit totally her unilateral market power and, therefore, bids at levels well below the cap. We discuss such a behaviour and derive implications for the setting of the price cap.Electricity auctions, capacity constraints, price cap, optimal bidding

Deregulated Wholesale Electricity Prices in Italy.

In this paper we analyze the time series of daily average prices generated in the Italian electricity market, which started to operate as a Pool in April 2004. The objective is to characterize the high degree of autocorrelation and multiple seasonalities in the electricity prices. We use periodic time series models with GARCH disturbances and leptokurtic distributions and compare their performance with more classical ARMA-GARCH processes. The within-year seasonal variation is modelled using the low frequencies components of physical quantities, which are very regular throughout the sample. Results reveal that much of the variability of the price series is explained by deterministic multiple seasonalities which interact with each other. Periodic AR-GARCH models seem to perform quite well in mimicking the features of the stochastic part of the price process.Electricity auctions, Periodic Time Series, Conditional Heteroskedasticity, Multiple Seasonalities

A robust multivariate long run analysis of European electricity prices

This paper analyses the interdependencies existing in wholesale electricity prices in six major European countries. The results of our robust multivariate long run dynamic analysis reveal the presence of four highly integrated central European markets (France, Germany, the Netherlands and Austria). The trend shared by these four electricity markets appears to be common also to gas prices, but not to oil prices. The existence of long term dynamics among electricity prices and between electricity prices and gas prices may prove to be important for long term hedging operations to be conducted even in countries where well established and liquid electricity derivatives markets are not present. Since standard unit root and cointegration tests are not robust to the peculiar characteristics of electricity prices time series, we adapt and further develop a battery of robust inference procedures that should assure the reliability of our results.European electricity prices, Cointegration, Interdependencies, Equilibrium Correction model, Oil prices, Robustness

Deregulated Wholesale Electricity Prices in Europe

This paper analyses the interdependencies existing in the European electricity prices. The results of a multivariate dynamic analysis of weekly median prices reveal the presence of strong integration (but not perfect integration) among the markets considered in the sample and the existence of a common trend among electricity prices and oil prices. This implies that there are no long-run arbitrage opportunities. The latter result appears to be relevant also in the context of the discussion of efficient hedging instruments to be used by medium-long term investors.European electricity prices, Cointegration, Interdependencies, Equilibrium Correction model, Oil prices

A Robust Multivariate Long Run Analysis of European Electricity Prices

This paper analyses the interdependencies existing in wholesale European electricity prices. The results of a multivariate long run dynamic analysis of weekly median prices reveal the presence of a strong although not perfect integration among some neighboring markets considered in the sample and the existence of common long-term dynamics of electricity prices and gas prices but not oil prices. The existence of long-term dynamics among gas prices and electricity prices may prove to be important for long-term hedging operations to be conducted even in markets where there are no electricity derivatives.European Electricity Prices, Cointegration, Interdependencies, Equilibrium Correction Model, Oil Prices

Electricity prices and cross-border trade: volume and strategy effects

In this paper we derive equilibrium bid functions in isolated domestic electricity markets and then analyse their modifications when cross-border trade among them is managed using the implicit auction method. We show that cross-border trade can induce price convergence across countries and thereby reallocate gains and losses as a result of two concomitant effects: a “volume” effect due to the mere increase/decrease of demand and supply in each market and a “bid effect” due to the modifications of bid functions brought about by interconnection. The latter effect can either contrast or reinforce the former. We derive conditions affecting the net result.Electricity markets; implicit auctions; cross-border trade

Risk of temporomandibular joint effusion related to magnetic resonance imaging signs of disc displacement

Background: It has been suggested that TMJ effusion may represent an inflammatory response to a dysfunctional disc-condyle relationship. The purpose of the present study was to evaluate whether the status of the disc in the temporomandibular joint, as depicted in magnetic resonance (MR) images, is predictive of the presence of temporomandibular joint (TMJ) effusion. Methods: The relationship between disc displacement and TMJ effusion was analyzed in MR images of 154 TMJs in 77 patients complaining for pain and/or dysfunction in the TMJ area and referred from medical practitioners to specialist consultation. Logistic regression analysis was used to identify the significant correlation between presence/absence of joint effusion and disc displacement. Results: Significant correlation (P<0.01) between disc displacement and joint effusion was found. OR for all type of disc displacement was 3.1, and the odds that a joint had magnetic resonance imaging findings of effusion was greater for anterior disc displacement without reduction. Conclusions: The status of the disc could represent a factor involved in the development of temporomandibular joint oedema. However, these findings suggest that disc displacement may not be regarded as the dominant factor in defining the occurrence of TMJ effusion. Certain local or systemic conditions other than the disc-condyle relationship must be considered

Electricity prices and cross-border trade: volume and strategy effects

In this paper we derive equilibrium bid functions in isolated domestic electricity markets and then analyse their modifications when cross-border trade among them is managed using the implicit auction method. We show that cross-border trade can induce price convergence across countries and thereby reallocate gains and losses as a result of two concomitant effects: a “volume” effect due to the mere increase/decrease of demand and supply in each market and a “bid effect” due to the modifications of bid functions brought about by interconnection. The latter effect can either contrast or reinforce the former. We derive conditions affecting the net result