The influence of climatological variables on the regional electricity demand


International Seminar of Regional Impacts of Climate Change, Agenzia Regionale per la Protezione dell’Ambiente della Lombardia, Milan, November 25-26, 2004

The main purpose of this report is to introduce some preliminary results concerning the study of the relationships between meteorological and climatological variables and the electrical energy demand. This research activity is part of the EXTRA project, a research project supported by MAP (Italian Ministry for Productive Activities), in the frame of the Public Interest Energy Research Project named “Ricerca di Sistema” (MAP Decree of 28 February 2003).

The research activities are constituted by three distinct phases:

  • evaluation of the reliability of Atmospheric and Oceanic General Circulation Models (AOGCM);

  • evaluation of the connections between electric variables (such as the electrical energy demand) and meteorological variables affecting the energy market, by means of climatological indices (such as the North Atlantic Oscillation Index – NAOI and El Niño Southern Oscillation Index – SOI);

  • evaluation of the influence of meteorological and climatological variables on the electrical energy demand.

The preliminary results concerning the first and second phase are (Apadula et al., 2004):

  • models agree on a temperature increase over the whole Italian peninsula during the 21st century;

  • such temperature increase is expected to be more pronounced at the higher than the lower latitudes;

  • the temperature increase will be more marked during summertime;

  • the temperature increase will be more evident in the maximum temperature values;

  • no trend is expected concerning the precipitation;

  • a persistence of the present NAO regime (a negative NAOI during autumn and a positive NAOI in the winter) is probable.

Finally, about the third phase, some comparisons between meteorological and climatological variables and the regional electrical energy demand are presented (Apadula, 2004). The analysed events consist in the “heat waves”. Heat wave is a period of abnormally and uncomfortably hot and usually humid weather. It is often associated with stationary domes of high pressure and can be classified (Capizzi, 2003) as follows: short-lasting (3 to 4 days) and long-lasting (5 to 15 days).

Some model results (Meehl et al., 2004) considered two severe heat wave events in Europe and North America, (Chicago 1995 and Paris 2003), and showed that heat waves in such areas are likely to become more intense, more frequent and longer lasting in the second half of the 21st century.

Heat waves are associated with considerable effects in terms of human health. In 2003, for instance, various estimates showed that the Paris heat wave took between 7,000 and 15,000 lives (an estimated 2,000 died in Italy).

They also have economical and ecological impacts: in particular, for electrical energy demand, the impact during summertime is not negligible.

The analysed “heat waves” events (in particular the case study of June 2002) have been proved to be particularly meaningful in order to study the relationships between meteorological and climatological variables and the regional electrical energy demand (in particular for Lombardy region).

The main result of this approach shows an evident and certainly not negligible connection between some meteorological variables, such as temperature and relative humidity, and the regional electrical demand.

To evaluate the joint effect of these two variables the Heat Index has been used (Bacci et al., 2002) . The results show (considering the daily mean regional electrical demand) a leap of about 800 MW for Sundays involved in a long-lasting heat wave (figure 1 and 2). The increased electrical demand is substantially due to the intensified use of the air conditioning systems. The heat waves effect on the electrical demand is also distinguishable on the monthly mean values.

In spite of all the difficulties related to climate modelling, our preliminary results are extremely interesting both at a short term and seasonal term scales. It is undoubtedly interesting to keep on doing research on the field, because the evident relationships between climate variability and change and electric demand have very significant impacts also from an economical point of view, in terms of electric market.


[Apadula et al., 2004] Apadula F., G. Lentini, M. Maugeri, 2004. Previsioni a medio e lungo termine delle variabili meteoclimatiche che influenzano il mercato elettrico: i modelli climatici, Rapporto RdS A4511660.

[Apadula F., 2004] Apadula F., 2004. Previsioni a medio e lungo termine delle variabili meteoclimatiche che influenzano il mercato elettrico: indici biometeorologici e radiazione solare globale, Rapporto RdS A4524029

[Bacci et al., 2002] Bacci L., M. Morabito, 2002. Gli indici biometeorologici nella valutazione dello stato di benessere dell’uomo, collana scientifica IBIMET – CNR, Firenze.

[Capizzi P., 2003] Capizzi P., 2003. Onde di calore: evento di giugno 2002 ed effetti sulla salute, Rivista di Meteorologia Aeronautica, N. 2/2003.

[Meehl et al., 2004] G. A. Meehl and C. Tebaldi, 2004. More intense, more frequent and longer lasting heat waves in the 21st Century, Science, Vol. 305, No. 5686, pp. 994-997.