Sunday, April 03, 2005

The government stole my hour!

If there's one government mandate we can all hate together, surely it is Daylight Saving Time. Reading this, we are reminded that DST was not intended to help farmers; urban businesses were supporters. Some further cursory googling of my own reveals that most of Indiana does not have DST because of farming interests in that state. Then there's the energy-saving justification for DST: the article I linked to above gives a few anecdotal counter-arguments to this justification, but no data. In looking for numbers, all I could find are references to "studies from the 1970s" and, less vaguely, to a 1975 DOT study. Then I found this 2001 testimony from a DOT official to the Energy Subcommitee of the House Science Committee:
Our 1975 study concluded that daylight saving time might result in electricity savings of 1 percent in March and April, equivalent to roughly 100,000 barrels of oil daily over the two months. These savings were calculated from Federal Power Commission data for only four daylight saving time transitions -- in the winter, spring and fall of the 1974 - 1975 experiment. Due to the limited data sample, the findings were judged "probable", rather than conclusive. Theoretical studies of home heating fuel consumption identified small savings due to daylight saving time. No potential increases in travel demand and gasoline use due to daylight savings time were identified at that time. The lack of actual data precluded an estimation of net daylight saving time energy savings. (emphasis added)
The poor quality of this study doesn't seem be generally known. For example, this California Energy Commission webpage doesn't seem to know about that "lack of actual data":
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.
Moreover, it's not "each day" of DST. DST doesn't start until March is over, and the only other month the DOT found energy savings was April. That leaves May through October with a big question mark.

Is there any better data out there? The California Energy Commission also did some regression analyses that predicted that making DST year-round instead of just April-October would cut California winter electricity use by half a percent. They also predicted "summer double DST" would cut California summer electricity use by a fifth of a percent and "could save hundreds of millions of dollars" by shifting electricity use to low demand morning hours. I'd like to see a national version of this study. I'd also like to see a study that estimates the net energy savings of ending DST, rather than just the net energy savings of intensifying it.

As best I can tell, DST very very slightly more likely than not saves America energy. Does this make the inconvenience worth it? Not to me: I want my hour back, or in lieu of that, some conclusive energy savings evidence.

Update: I should point out that the DOT study only looked at energy savings in March and April because it was trying to determine the merits of having DST start earlier, not the merits of DST itself. This reinforces my point about the lack of data on the merits of DST.

3 Comments:

Anonymous Anonymous said...

Instead of forcing the government to get involved in changing the calendar, why shouldn't American society just start their day an hour earlier in California? Start schools an hour earlier, have jobs start at 8 instead of 9, and move Primetime TV programming back an hour.

4/05/2005 3:39 PM  
Blogger Dave Milovich said...

There are strong network effects that discourage changing one's schedule unless everyone you interact with also changes. These same network effects, along with simple inertia, also make it hard for me to realize my dream of ending DST. Moreover, I suspect starting another hour earlier is a very unpopular idea.

4/05/2005 7:03 PM  
Anonymous t_rex said...

Just wait 'til next year when DST starts the 2nd Sunday in March and lasts to the 1st Sunday in November. I'll campaign to continue the trend to expand DST until it lasts all year long, then you'll never get that hour back! But we'll need to ban you from living in a timezone west of your birthplace.

4/02/2006 4:22 AM  

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