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Just as sunflowers turn their heads to catch every sunbeam, so too have we discovered a simple way to get more from our sun

 One of the biggest reasons we change our clocks to Daylight Saving Time (DST) is that it reportedly saves electricity. Newer studies are being done to see if that long-held reason is true.

In general, energy use and the demand for electricity for lighting our homes is directly connected to when we go to bed and when we get up. Bedtime for most of us is late evening through the year. When we go to bed, we turn off the lights and TV.

In the average home, 25 percent of all the electricity we use is for lighting and small appliances, such as TVs, VCRs and stereos. A good percentage of energy consumed by lighting and appliances occurs in the evening when families are home. By moving the clock ahead one hour, we can cut the amount of electricity we consume each day.

Studies done in the 1970s by the U.S. Department of Transportation show that we trim the entire country's electricity usage by about one percent EACH DAY with Daylight Saving Time.

Daylight Saving Time "makes" the sun "set" one hour later and therefore reduces the period between sunset and bedtime by one hour. This means that less electricity would be used for lighting and appliances late in the day. We may use a bit more electricity in the morning because it is darker when we rise, but that is usually offset by the energy savings in the evening.

We also use less electricity because we are home fewer hours during the "longer" days of spring and summer. Most people plan outdoor activities in the extra daylight hours. When we are not at home, we don't turn on the appliances and lights. A poll done by the U.S. Department of Transportation indicated that Americans liked Daylight Saving Time because "there is more light in the evenings / can do more in the evenings."

While the amounts of electricity saved per household are small...added up they can be very large.

In the winter, the afternoon Daylight Saving Time advantage is offset by the morning's need for more lighting. In spring and fall, the advantage is less than one hour. So, Daylight Saving Time saves energy for lighting in all seasons of the year except for the four darkest months of the year (November, December, January and February) when the afternoon advantage is offset by the need for lighting because of late sunrise.

A report was released in May 2001 by the California Energy Commission to see if creating an early DST or going to a year-round DST will help with the electricity problems the state faced in 2000-2002.

You can download an Acrobat PDF copy of the staff report, Effects of Daylight Saving Time on California Electricity Use, Publication # 400-01-13, (PDF file, pages, 5.2 megabytes).

The study concluded that both Winter Daylight Saving Time and Summer-season Double Daylight Saving Time (DDST) would probably save marginal amounts of electricity - around 3,400 megawatt-hours (MWh) a day in winter (one-half of one percent of winter electricity use - 0.5%) and around 1,500 MWh a day during the summer season (one-fifth of one percent of summer-season use - 0.20%). Winter DST would cut winter peak electricity use by around 1,100 megawatts on average, or 3.4 percent. Summer Double DST would cause a smaller (220 MW) and more uncertain drop in the peak, but it could still save hundreds of millions of dollars because it would shift electricity use to low demand (cheaper) morning hours and decrease electricity use during higher demand hours.

The Energy Commission has also published a new report titled The Effect of Early Daylight Saving Time on California Electricity Consumption: A Statistical Analysis. Publication # CEC-200-2007-004, May 27, 2007. (PDF file, 592 kilobytes)

In May 2001, the California state legislature sent a Senate Joint Resolution (SJRX2 1) to the White House and Congress asking that states be allowed to extend Daylight Saving Time year round. Congress and the White House did not act on the request because of the world-changing events of September 11, 2001. No new legislation has been passed in California since then.

A more recent study - in draft form as of February 2008 - by Matthew Kotchen and Laura Grant of the University of Santa Barbara concludes that Daylight Saving Time in Indiana actually increases residential electricity demand. That study titled "Does Daylight Saving Time Save Energy? Evidence From a Natural Experiment in Indiana". (PDF file) looked at the electricity use when portions of the state finally started to observe DST. Before the new extended DST, portions of Indiana did not observe DST.

Some have wondered whether this study would be true for the entire United States. Initial analysis by staff of the California Energy Commission says a similar study may not yield the same results for California because:

• The use of residential air conditioning is relatively low in Indiana, and the saturations are low. Where as California has high usage of air conditioning in the summer.
• Heating use is relatively high in Indiana, while it is relatively low in California.
• The diurnal variation in temperature is low while California is very high.
• Indiana is located in western edge of the same time zone as Maine and Florida, but the sun actually comes up at an earlier time than those other two states.
• Indiana's north-south location will affect how long the days are in the summer and might very well lead to different results in different areas.

So, while the analysis is of interest to Indiana, it's conclusions may not be totally correct for California or the rest of the country. Additional studies on electricity savings, the first national study since the 1970s, are being done by the U.S. Department of Energy, and more definitive results on DST on electricity use will be coming in the next year or two.

But why do we have Daylight Saving Time to begin with? Who created the laws and regulations that we follow?

History of Daylight Saving Time

 Daylight Saving Time is a change in the standard time of each time zone. Time zones were first used by the railroads in 1883 to standardize their schedules. According to the The Canadian Encyclopedia Plus by McClelland & Stewart Inc., Canada's "[Sir Sandford] Fleming also played a key role in the development of a worldwide system of keeping time. Trains had made obsolete the old system where major cities and regions set clocks according to local astronomical conditions. Fleming advocated the adoption of a standard or mean time and hourly variations from that according to established time zones. He was instrumental in convening an International Prime Meridian Conference in Washington in 1884 at which the system of international standard time -- still in use today -- was adopted."

In 1918, the U.S. Congress made the U.S. rail zones official under federal law and gave the responsibility to make any changes to the Interstate Commerce Commission, the only federal transportation regulatory agency at the time. When Congress created the Department of Transportation in 1966, it transferred the responsibility for the time laws to the new department.

The American law by which we turn our clock forward in the spring and back in the fall is known as the Uniform Time Act of 1966. The law does not require that anyone observe Daylight Saving Time; all the law says is that if we are going to observe Daylight Saving Time, it must be done uniformly.

Daylight Saving Time has been around for most of this century and even earlier.

Benjamin Franklin, while a minister to France, first suggested the idea in an essay titled "An Economical Project for Diminishing the Cost of Light." The essay was first published in the Journal de Paris in April 1784. But it wasn't for more than a century later that an Englishman, William Willett, suggested it again in 1907.

Willett was reportedly passing by homes where the shades were down, even though the sun was up. He wrote a pamphlet called "The Waste of Daylight" because of his observations.

Willett wanted to move the clock ahead by 80 minutes in four moves of 20 minutes each during the spring and summer months. In 1908, the British House of Commons rejected advancing the clock by one hour in the spring and back again in the autumn.

Willett's idea didn't die, and it culminated in the introduction of British Summer Time by an Act of Parliament in 1916. Clocks were put one hour ahead of Greenwich Mean Time (GMT) during the summer months.

England recognized that the nation could save energy and changed their clocks during the first World War.

In 1918, in order to conserve resources for the war effort, the U.S. Congress placed the country on Daylight Saving Time for the remainder of WW I. It was observed for seven months in 1918 and 1919. The law, however, proved so unpopular that it was later repealed.

When America went to war again, Congress reinstated Daylight Saving Time on February 9, 1942. Time in the U.S. was advanced one hour to save energy. It remained advanced one hour forward year-round until September 30, 1945.

In England, the energy saving aspects of Daylight Saving were recognized again during WWII. Clocks were changed two hours ahead of GMT during the summer, which became known as Double Summer Time. But it didn't stop with the summer. During the war, clocks remained one hour ahead of GMT though the winter.

From 1945 to 1966, there was no U.S. law about Daylight Saving Time. So, states and localities were free to observe Daylight Saving Time or not.

This, however, caused confusion -- especially for the broadcasting industry, and for trains and buses. Because of the different local customs and laws, radio and TV stations and the transportation companies had to publish new schedules every time a state or town began or ended Daylight Saving Time.

By 1966, some 100 million Americans were observing Daylight Saving Time through their own local laws and customs. Congress decided to step in end the confusion and establish one pattern across the country. The Uniform Time Act of 1966 (15 U.S. Code Section 260a) created Daylight Saving Time to begin on the last Sunday of April and to end on the last Sunday of October. Any area that wanted to be exempt from Daylight Saving Time could do so by passing a local ordinance. The law was amended in 1986 to begin Daylight Saving Time on the first Sunday in April.

ave we discovered a simple way to get more from our sun.