Does daylight-saving time really save energy?

When I was a paper boy back in the 1980s, I always hated daylight-saving time. Just when the mornings were finally starting to lighten after a long, dark winter, daylight-saving time came along and ruined everything: when clocks "spring" forward, the sunrise arrives one hour later. It would be several weeks before I'd be able to deliver my papers in the light. This weekend, daylight-saving time arrived even earlier than usual, thanks to a new law supposedly designed to save energy.

Since many people are still asleep while it's light outside in the morning, the reasoning goes, all that light is wasted, and in the evenings when more people are awake, they use more energy because they must turn on lights. Daylight-savings time allows people to use natural light when they are actually awake. On the other hand, if it's light later at night, then more people might be encouraged to go out -- for shopping, exercise, and so on -- and any energy saving might be lost. ABC news reports on a study suggesting another reason extending daylight saving time may not work:

Ryan Kellogg and Hendrik Wolff compared electric demand in the state of Victoria, which extended DST, with its next-door neighbor, South Australia, which did not.

"Our results show that the extension failed to conserve electricity," they wrote.

"If it's dark enough in the morning that pretty much everyone has to turn on the lights," said co-author Kellogg, "what that means is that that increase in morning electricity consumption is going to be so big that it offsets any benefits we get from the extra light in the evening."

In fact, the two said, shifting Australians' clocks led to a tiny increase in power use.

A Scientific American article also casts doubt on the notion that daylight-saving time helps conserve much energy:

Some studies dispute the energy savings would be as great. A recent analysis by the California Energy Commission, for instance, concluded that the change would shift&rather than reduce--electricity use to off peak hour. The report said that electricity use could dip by 0.5 percent--or less. A shift to off peak electricity use still has the advantage of lowering the capacity requirements for utilities, but it's questionable whether the savings would be as much as the ACEEE estimates.

I don't deliver papers any more, but it's still a little depressing to wake up every morning in darkness. The department of Energy is charged with monitoring this new change in policy to see whether the energy savings are real (the law will be repealed if there are no savings). For the sake of groggy paper boys across the country, I hope they aren't.


More like this

I rebel against DST.

I do everything an hour early, and I switch my clocks from Pacific Standard Time to Mountain Standard Time. Ha -- they never catch on!

And my electric bill shows no difference. Zero.

Obviously more people are awake in early evenings than in early mornings. However, the problem is that if you have to turn on the light in the morning, you sometimes forget to turn it off, because it is harder to notice that the light is still on when it gradually becomes brighter outside, and you aren't likely to notice it until you are back home or it becomes dark again. If every day just 10% lights are accidentally left on for 11 hours instead of 1 hour, the total consumption will double.

Personally I love daylight saving time even if it doesn't conserve energy, just for the outdoor activities in late afternoons.

I'm originally from Connecticut and Philadelphia, but I currently live in Michigan. All of these places are in the eastern time zone. But Michigan is obviously far west of the places I lived for 23 years. So, while I like eating my dinner while it's still light out in the summer (beyond 9PM, even!) I really don't like waking up and leaving for school when it's still dark out during the rest of the year. In the winter, the sun rises around 8am here. In the past few weeks the sun was beginning to rise early enough such that it would be partially or mostly light by the time I woke up, but this morning it was pitch black when the alarm went off. As Dave mentioned, this means we have to turn all of our lights on while we get ready in the morning. And as someone else suggested, perhaps we'll forget to turn them off when we leave!

I like daylight savings time in the summer, because it's true that I don't want the sun to be rising at 5am and of course I love sun in the evening. But for my lifestyle/location within the time zone, moving daylight savings to March will be more likely to cause me to waste energy than save it, and it will cause me to be grumpy because I prefer to wake up to the sun rising.

By Katherine (not verified) on 12 Mar 2007 #permalink

Daylight saving time is one of my obsessions. I live in the Arctic and the early DST serves only to plunge us back into darkness when getting up in the morning. After having to contend with the long, dark winter nights this chronometric tinkering serves only to depress. I too refuse to change my clocks and have adjusted my schedule instead.

Let's hope there is an actual audit of this folly and that wiser and less greedy minds will prevail in 2008.

As a definite non-morning person (I don't get up before 9am and usually leave work around 7pm) I have to say I love daylight savings time. I've always found it annoying that the world is run by early-morning people. :)

I don't know about whether or not daylight savings time at all affects energy use, but, like you, my primary association with the whole phenomenon is still the somewhat depressing return to in-the-dark paper delivery from my childhood.

My solution:

Refuse to get up before noon. If it feels like 11 am when it's time to get up, I can live with that.

Now if I could just get my boss to agree...

who's consuming energy these days?

back when the arguments in favor of "energy conservation" were made, many offices still had incandescent bulbs, not florescents, and most places had private lighting for individual workspaces.

today, the modern cube office is sometimes lit up 24/7. often even if not that, then at least the entire floor is lit even if only one person is in the hall. and they're lit up all day. the modern office simply doesn't really turn their lights off in reflection of the hours of the sun - if someone's in, they're on.

similarly, factory floors have all moved to 24/7 lighting as part of union safety rules.

at home? 1) i'm rarely home before the sun goes down, even on a good day, and 2) even if i am, half the rooms i'm in i still have lights on 'cause the sun can't get everything.

and, of course, DST has no effect at all on gas consumption.

so where's the change? our lifestyle has changed so much in the last 40 years that the very things they assert would change simply don't. our lights are on, in full, all the time (e.g., i'm in a grocery store on a cloudless day, but not a single light is off in the whole building). what hour the sun actually rises doesn't change that at all.

By Joe Shelby (not verified) on 12 Mar 2007 #permalink

The only argument I have in favor of getting rid of it, is that most of the population calls it Daylight SAVINGS Time. It is Daylight Saving Time. Once we can get past that cognitive error, I will be all for DST.

As my wife just noted in the morning, how this is supposed to safe any energy if before she was not turning the light on during the morning routine and now she has to?
And in the reply to the #3. You forget to turn off the light not because you don't see it. But because:
1. waking up in the dark makes you groggy and you lack proper attention.
2. you try to stay as long as you can in bed because it is dark and also cold (since there is no heat from the sun yet) outside and than you rush things because you have to be at work at a certain time and obviously you can forget small things when you are under self-indict "pressure".

No one has mentioned the worst part about Daylight Saving Time (there you go, Anthony) - having small children who don't change their internal clock nearly as quickly as adults do and now that eight o'clock bedtime is nine o'clock and I have NO time to get any projects done! Messes up schedules for at least a week, if not more - I wish they would just cancel it!

If you hate all this messing around with the clock as I do, then learn to live in metric time. The rest of the city, country, state - whatever - can do what it likes. Your clock always stays the same. Insist that everyone convert their time to yours before making an appointment or whatever. It's amusing to ask someone to meet you after work at 7:75.

Plus you only work for 3.5 metric hours if you work a regular day.

As an amateur astronomer DST means I have to stay up an hour later at night to view a dark sky.

And to build on Anthony's point. There is no daylight savings. The Sun comes up; the Sun goes down; on schedule, no mater what we do with our clocks. There is no additional daylight. In a 24 hour working world I suspect there is little energy savings.

Everyone i know is jetlagged. Feh.

Back in the day, i lived in Indiana, which, way back then, did not observe DST. I thought of it as Eastern time for half the year, and Chicago time the other half. Most of the cable TV stations were based in Chicago - which worked for me. Indiana is at the west end of the Eastern time zone, so this made perfect sense to me.

Now i live in Michigan. It should be noted that the upper pennisula isn't just in the western end of the eastern time zone. It's a good ways into the central zone.

So, i lost an hour of sleep. I've looked all over for it. It's not under the sofa or anything.

i'd rather have sunlight when i'm fully awake in the afternoon than when i'm half-asleep in the morning. it's terribly depressing to leave school to encounter darkness at the end of a long day -- all daylight hours are spent inside a cinderblock building! i like having this little tail of light at the end.

Not quite "raging against the machine" but my wife likes to kid me when I refer to "real time". I refuse to acknowledge the legitimacy of DST and spend the 1st few weeks after the switch referring to what the non-DST time would be...

Getting up in the morning is unpleasant regardless. I always thought daylight saving time was all about giving us an extra hour of sunlight in the latter part of the day. For those of us who aren't morning people, daylight savings is a huge blessing. Everyone I know (generalisation! yay!) is depressed when we lose it and celebrates it when it arrives.


By Dana Izard (not verified) on 25 Mar 2007 #permalink

I think that Daylight Saving Time is no good and waste energy. It does not make sense at all. Why? Because it is morning darkness, it do waste electricity and energy!!

I think that it stinks.

By Michael J Hutchinson (not verified) on 07 Apr 2007 #permalink

Well here we are a yeal later and questions need to be answered by our Congress. Last year three weeks after the change 3 weeks earlier after a month of the GREAT experiment Lundberg Reports issued a report saying that gasoline prices rose quicker than usual because the people driving later at night earlier than usuals caused the gasoline prices to rise quicker - duh - Congress what you to go out and drive and spend money the result we wasted more gas! Duh these politicians are rocket scientists. Despite reports on the net showing when Australia tried the same type of experiment for the Olympics in Sydney they actually used more energy - duh! Then last fall the children in the Northeast walked to school the last week of October and first of Novemeber in the dark - really smart considering all the kids that kidnapped, molested or worse just disapperar - duh!

Now this year we are again changing clocks early and with the record high oil rpices worse than last year and the three week changing the clocks early will result in a quicket draw down of gas inventory resulting in the gas price marching to 4.00 a gallon quicker. These elected officials are screwing us - and we must be enjoying it because we al letting them do it!