The annual gas demand for Italy is processed for the various sectors of use (according to the classification used by the National Energy Balance) through econometric models that take into account the development over time of the economic and energy indexes of the various sectors and the development of the competitiveness between energy sources.
Particular attention is paid to the thermoelectric power generation sector, where the forecast for gas demand is obtained through a computational model that takes into account the expectations of electricity demand, fuel competitiveness, among fuels and among generation technologies and the competition among plants. The projections for power stations development is obtained through commercial information, the development plans of the main sector operators and any other source deemed reliable. Typically, the time forecast covers a period of ten years.
The expectation of demand at the national level is subdivided over the territory by taking into account the localisation of the re-delivery points, in order to provide a geographical distribution of consumptions on the natural gas transmission network. The evolution of consumption at each re-delivery point is processed using linear regression models that consider historical withdrawals, assigned capacity, recorded load factors and any other available technical and commercial information, which might be available and can be used to establish a gas demand forecast.
In addition to the geographical transmission of the demand forecast, the time transmission profile of withdrawals over the year is modeled. In fact, the daily scenarios of Daily gas demand have a significant variability over the course of the year since they are influenced both by the seasonal climate and by the cyclical nature of the industrial production. Daily scenarios are obtained by simulating the annual scenario through daily coefficients specific to each re-delivery point, processed from the daily usage history. To assess specific and critical situations on the gas transmission network, daily scenarios of "extreme" demand are also simulated at daily resolution, such as gas demand in conditions of extreme cold, scenarios of summer minimum usage of the transmission network, or scenarios of gas demand that take into account exogenous factors including, for example, the unavailability of electricity production from renewable sources or a momentary lack of electricity import from abroad.
As an indication, the ratio between the winter daily average demand and the summer one is about 2 to 1 in standard conditions, while it reaches to 3 to 1 in conditions of extreme cold.