Trends in energy load demand for Athens, Greece: weather and non-weather related factors

This study examines the characteristics of energy demand for the Greater Athens area in Greece, and explores its relationship with variations in temperature. Energy demand in Athens varies both seasonally and from year to year. The latter shows an increasing trend, which is associated mainly with economic, social and demographic factors. The former is controlled by prevailing weather fluctuations and also by factors unrelated to weather effects (weekend and holiday effects). Weekends and public holidays always appear to have much lower values of energy demand than weekdays. Analysis of our data series has indicated that the relation between energy demand and temperature is non-linear and that the optimum ambient temperature for low levels of energy demand is 22 degrees C. This temperature was also used as the base temperature for the calculation of heating and cooling degree-days. The sensitivity of energy load to air temperature is greater during the cold period of the year. Under a changing climate, regional models predict a warming for Athens by the 21st century that will be associated with a decrease in demand during the milder and shorter winter period and with an increase in demand during the hotter and longer summer period.