Daylight effect on the electricity demand in Spain and assessment of Daylight Saving Time policies

Abstract

Daylight Saving Time (DST) policies have been in use since early in the 20th century. However, their energy saving effect is under review. The generalization of LED lighting has reduced the impact of lighting energy on the total energy consumption and, therefore, the effect of DST has been reduced. Nevertheless, in order to design an effective new policy in this aspect, it is necessary to understand how total electricity consumption would be affected by it but also how the load daily profile would change. This paper proposes an hourly load model that quantifies the effect of daylight on electricity consumption and simulates the effect of different DST policies. The model is applied to the inland Spanish electricity system and the three scenarios more likely to be implemented if current DST policy is changed: year round winter time (UTCþ1), year round summer time (UTCþ2) and keep DST but change clock 1 h back (GMT). The results show how changes in sunrise and sunset times affect daily load profiles. They provide overall, monthly and hourly energy savings for each scenario that are necessary for a wellinformed DST policy design and implementation.