Question:

How does daylight savings time save energy, and how much?  Please enlighten me!

Answer:

Daylight savings time refers to the practice of adjusting the official time, usually by one hour, in the spring or summer and early fall. The goal is to save energy by making our hours of activity coincide with natural sunlight to limit the use of artificial lighting. Many countries take this approach, particularly in temperate regions where seasonal variations in daylight make it useful. In France, daylight savings time was established in 1975 after the first oil shock of 1974. Estimates produced in 1996 and 2006 indicate that the annual energy savings vary from 0.7 to 1.2 billion KWh. The latter figure represents 4% of all electricity used for lighting in France, or the entire electricity consumption of a city of 200,000 inhabitants for an entire year.