The Importance of Time Zone Assignment: Evidence from Residential Electricity Consumption

This paper presents the first nationwide empirical assessment of residential electricity use in response to the timing of daylight. Employing Geographical Information Systems (GIS) solar times of sunrise and sunset are calculated for all geographical locations in mainland USA. This is used to uncover the non-standard variation in sunrise times in standard local time over space, depending on time zone, daylight saving time, and geographical position within time zone. This variation is subsequently used to uncover county-level responses in residential electricity consumption to changes in sunlight. I find no robust overall effect of sunrise times, but early sunrise is associated with lower residential electricity use in the North, but higher consumption in the South. These results would suggest that additionally splitting the USA into time-zones horizontally could reduce the total annual residential electricity bill, but further research is needed to examine the behavioral channels that could give rise to these effects.