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Daylight savings time increases energy usage
There is a natural experiment from the recent switch away from DST in Indiana. Matthew Kotchen and Laura Grant report:
Our main finding is that—contrary to the policy’s intent—DST increases residential electricity demand. Estimates of the overall increase range from 1 to 4 percent, but we find that the effect is not constant throughout the DST period. There is some evidence of electricity savings during the spring, but the effect lessens, changes sign, and appears to cause the greatest increase in consumption near the end of the DST period in the fall. These findings are consistent with simulation results that point to a tradeoff between reducing demand for lighting and increasing demand for heating and cooling. Based on the dates of DST practice before the 2007 extensions, we estimate a cost of increased electricity bills to Indiana households of $8.6 million per year. We also estimate social costs of increased pollution emissions that range from $1.6 to $5.3 million per year.
In other words, with DST less is spent on light but more is spent on air conditioning. Here is a summary article on the work, from today's WSJ. Do note this:
There may also be social benefits to daylight-saving time that weren't covered in the research. When the extension of daylight-saving time was proposed by Mr. Markey, he cited studies that noted "less crime, fewer traffic fatalities, more recreation time and increased economic activity" with the extra sunlight in the evening.
Posted by Tyler Cowen on February 27, 2008 at 10:37 AM in Economics | Permalink
Comments
I've heard just the opposite about traffic fatalities, mainly because people lose an hour of sleep in the spring.
Posted by: Akshay Kapur at Feb 27, 2008 10:49:14 AM
A big complaint in northern states was by parents who are now sending their kids to the school bus stop in the dark in the morning (or opting instead to drive them to school -- so much for reducing energy use).
Posted by: KipEsquire at Feb 27, 2008 10:51:39 AM
First as a genuine engineer, I think we should all just operate on GMT and be done with it. The naming of time is arbitrary.
But beyond that, I've heard skeptical environmentalists argue in the past that DST would not reduce energy use, but would encourage shopping. Not sure how that works, but there's some fodder for data miners.
Posted by: odograph at Feb 27, 2008 10:55:28 AM
I'm not convinced by this. Mainly, I'm not sure that a handful of counties in the northwest (near Chicago) and a handful of counties in the sothwest and southest are a good enough control group for weather effects across the whole state. My guess is different weather resulted in different heating/cooling expenses. Do people really crank up the AC more when they get home from work? When it's hot enough to need it, I just set mine and leave it, so that it will already be cool when I get home.
Posted by: Brett at Feb 27, 2008 11:01:35 AM
Brett, you obviously did not read the paper. ALL of the counties were in the southern part of the state. Take a look at Figure 1. The counties labeled NW just happened to be in the northwest corner of the group of counties at the southern end of the state. They are nowhere near Chicago.
The article also provides a nice survey or previous work on estimating the savings from DST, most of which seems inconclusive. This paper seems consistent with previous work.
Posted by: John S. at Feb 27, 2008 11:14:48 AM
I hadn't read the paper, just part of the WSJ article. Just looking at the southern counties does make the control better. So no I may believe the results, but still don't understand them. Am I abnormal in that I just set my thermostat at one temperature and don't adjust it unless I'm going to be exclusively at home/away from home for a long period of time? My gut reaction to the DST thing is that it doesn't make much of a difference in energy consumption, one way or the other. Given that, I prefer for it not to already be dark when I leave work.
Posted by: Brett at Feb 27, 2008 11:21:36 AM
Does the paper account for the huge negative of giving everyone jet lag twice a year? Or the semiannual confusion and lost productivity from getting up too late or too early?
Posted by: happyjuggler0 at Feb 27, 2008 11:48:28 AM
Many people turn down the heat/AC when they go to work then turn it back up when they're home, if needed. The theory here seems to be that because of DST, people get home an hour early and are more likely to turn up the AC since it's hotter. And once it's on it probably stays on for more than an hour, since the alternative to the AC is opening windows and it doesn't make sense to do that once you've had the AC on.
Posted by: Hei Lun Chan at Feb 27, 2008 11:56:33 AM
given that in the summer there will be extra demand for cooling and in the fall for heating, how much of this is attributable to daylight saving time?
did they compare regions with similar climates and economies but with and without dst's? this would make it more believable to me
Posted by: DIS at Feb 27, 2008 11:57:53 AM
it's possible indiana is not a good test case because the hoosier state is geographically in the central time zone, not eastern.
Posted by: dav at Feb 27, 2008 12:06:32 PM
Kip-
By and large, the school year is conducted in the time when DST is NOT in effect, thus the whole "kids waiting for the bus in the dark" argument is a moot point. As a native Hoosier, I remember waiting for the bus in the dark or pre-dawn for 75% of the school year.
Posted by: Matt at Feb 27, 2008 12:06:50 PM
Day-
How is Indiana geographically in Central time? The line comes down from Canada through western Lake Superior, putting most of the U.P. of Michigan in Eastern, then down along the west coast of Lake Michigan. Indiana's western border makes a logical partition for the time zones.
Posted by: Matt at Feb 27, 2008 12:11:13 PM
They can take my extra hour of sunlight in the evening during the summer when they pry it from my cold, dead hands.
Indiana is a terrible example, because it is so far on the western side of the Eastern Time Zone, that they get plenty of light as it is during the evenings. For states on the eastern edge of the time zone, getting rid of daylight savings time just makes it light intolerably early in the summer, and prevents me from getting in a full 18 after work.
Posted by: vaildog at Feb 27, 2008 12:26:37 PM
I don't think GMT does anything for us in this case, though I have no problem with it being implemented here.
If our schedule was dawn oriented, we might be able to optimize these things a little better. Say 00:00 is dawn, you might be due at work at 02:00. For shift workers, it would be weird, with third shift at least working a little extra from winter solstice to summer solstice, then a little less from summer solstice to winter solstice.. I am sure there are practical problems beside "why the heck would we want to do that" and "the transition would be murder", but I think it is an interesting idea.
Posted by: anomdebus at Feb 27, 2008 12:48:49 PM
Another example of social engineering gone wrong. The government should get out of the "time travel" business and let people decide when and where they will go to work, etc. That may put a little less food on the tables of researchers, but it would relieve so much wasteful spillovers (just from switching...) as to be worth it. Nature went for millennia without clocks, and it's bad enough that we use them, but let's not abuse them!
Posted by: David Zetland at Feb 27, 2008 12:58:31 PM
The government should get out of the "time travel" business and let people decide when and where they will go to work, etc.
Isn't the government the country's biggest employer? So don't they have a hand in this already? Also, it would be more difficult for businesses to shift their hours on a seasonal basis. What's wrong with the government doing it if there are tangible benefits? Seems like an eminently reasonable thing for a democracy to decide on.
Posted by: mpowell at Feb 27, 2008 1:43:40 PM
What's wrong with the government doing it if there are tangible benefits?
If there are tangible benefits. That's the question here -- it seems that there is no good evidence of tangible benefits. It's an example of "faith based" policy-making--which unfortunately seems to be the norm for all types of government policies, ranging from drug prohibition to nation-building: somebody speculates that a policy should have a particular outcome, and the politicians treat it as revealed truth.
On the big picture, I agree that elected officials could play a role in coordinating seasonal changes to our schedules, but might it be more reasonable for them to simply declare "if you want to switch to a summer schedule (starting the day earlier), we suggest that everyone do it on March 4" -- and leave the clocks alone.
Posted by: Adam Ricketson at Feb 27, 2008 2:17:50 PM
What's wrong with the government doing it if there are tangible benefits?
If there are tangible benefits. That's the question here -- it seems that there is no good evidence of tangible benefits. It's an example of "faith based" policy-making--which unfortunately seems to be the norm for all types of government policies, ranging from drug prohibition to nation-building: somebody speculates that a policy should have a particular outcome, and the politicians treat it as revealed truth.
On the big picture, I agree that elected officials could play a role in coordinating seasonal changes to our schedules. But might it be more reasonable for them to simply declare "if you want to switch to a summer schedule (starting the day earlier), we suggest that everyone do it on March 4" -- and leave the clocks alone?
Posted by: Adam Ricketson at Feb 27, 2008 2:23:31 PM
Not having read the paper, I wonder whether these results are replicable in places where air conditioning is uncommon (i.e., the vast majority of the world, including Western Europe). Probably not.
Posted by: LemmusLemmus at Feb 27, 2008 2:46:28 PM
I am a born a bred Arizonan. We think the whole DST is bunk. As soon as you add air-conditioning to the energy consumption side of the equation day light savings become a myth. Daylight savings was thought up in an era when the only energy consumption in the typical home was lights or a radio. Today we have lights, computers, TVs, stereo systems, cooking, heating, cooling. Even if you do not turn a light on in your house for an additional hour, you still come home and turn on the TV, the computer, the stereo system, cook dinner. These remain constant throughout the year. Lighting is the smallest part of the mix. The only way you "save" electricity is if you are not home. Day light savings will become an even bigger myth as we all switch over to fluorescent light bulbs, which use significantly less energy than incandescent.
Air-conditioning. Don't most people just set it and forget it? Not so much anymore. Here in Arizona, you can realize significant energy savings by cycling your air conditioning. During the day, you let the house heat to about 85-90. This reduces the temperature delta to the outdoors from 30-40 degrees to 20-30 degrees. It takes significantly less energy to maintain a house at 90 than at 75 in the middle of the day. When you come home, you drop the temperature back to 75-80. It takes about 30 minutes to cool the house down. In addition, the temperature outside (since we peak at 4:00pm in the summer) is starting to come down aiding the cooling. In contrast, to maintain 75-80 throughout the day, the air-conditioner will run about 10 minutes every hour or about 80 minutes total. Programmable thermostats are a wonder of the computer age.
My favorite myth of daylight savings time is that it allows a farmer to get up later in the morning. Logically this makes no sense. A farmer works as long as there is light regardless of arbitrary time signals. Without DST, he would just get up earlier and go to bed earlier. Probably boosts TV ratings though.
Another myth of DST is that people will spend more time away from home after work if there is more daylight. That may have been true in an earlier era when all you could do if you went home was read a book, listen to the radio, play a board game or chat. However today there are just as may entertainment options inside the home as outside.
Posted by: NASCAR Wife at Feb 27, 2008 2:52:55 PM
Farmers. How quaint. Didn't we outsource all of those, too?
Posted by: meter at Feb 27, 2008 3:26:27 PM
Matt, the EXPANSION of DST occurs ENTIRELY during the school year.
Thanks for trying though.
Posted by: KipEsquire at Feb 27, 2008 3:34:15 PM
The engineer, the happy juggler, the NASCAR wife all just hint at the madness of DST. It is not that early light costs us more or that evening light costs us more, the changing clocks cost us either way.
For all of the people who claim to benefit from DST, for all of the studies that claim the "extra" time is better used in the morning, there seem to be just as many people who claim DST is bad, studies that claim that light time is better used in the evening.
It is ridiculous. Have been saying it for years.
Posted by: R N B at Feb 27, 2008 4:10:56 PM
Are there really people who struggle physically with the change from standard time to daylight time? It occurs on the weekend, and takes maybe two days to get used to. Why not just be on DST permanently? I prefer the light in the evenings, and suspect most normal people do as well.
Posted by: minturn at Feb 27, 2008 4:15:21 PM
I'm probably more libertarian than anyone here, but I don't see a problem with daylight savings time. After all, the government doesn't force anyone to set back their clocks. There is no law against ignoring daylight savings time, or changing your schedule around it that I know of (and if there is, would it ever really be enforced?).
Businesses will obviously do whatever they think is in their best interest, proclamations of "daylight" notwithstanding. Its easy to alter work hours twice during the year with or without government reminding us (easier, I would argue, than setting every damn clock back and building DST functionality into modern clocks).
Posted by: Grant at Feb 27, 2008 5:12:03 PM
