A statistical analysis of the energy policy act of 2005, its changes to the daylight saving program, and impact on residential energy consumption

Government programs designed to decrease resource consumption, improve productivity and capitalize on extended daylight hours in the summer have been developed and implemented throughout the world for nearly three hundred years. In 2005, The United States government adopted an extended daylight savings program that increases the number of weeks where the country observes Daylight Saving Time (DST) from 31 to 35 weeks. The program took effect in March 2007. Arguments in support of DST programs highlight the portion of electricity consumption attributed to residential lighting in the evening hours. Adjusting clocks forward by one hour in summer months is believed to reduce electricity consumption due to lighting and therefore significantly reduce residential energy consumption during the period of DST. This paper evaluates the efficacy of the changes to DST resulting from the Energy Policy Act of 2005. The study focuses on changes to household electricity consumption during the extended four weeks of DST. Arizona, one of two states that continue to opt out of DST serves as the study's control for a comparison with neighboring states, Colorado, Nebraska, Nevada, New Mexico, Oklahoma, Texas and Utah. Results from the regression analysis of a Difference in Difference model indicate that contrary to evaluations by Congress and the Department of Energy, the four week period of Extended Daylight Saving Time does not produce a significant decrease in per capita electricity consumption in Southwestern states.