Longer daylight time may save energy -- but stats are stale

Saturday, November 03, 2007

From a story by Carl Bialik in the Wall Street Journal:

Americans are turning their clocks back this Sunday -- one week later than last year. With the earlier start this past March, that translates into four extra weeks of daylight-saving time.

The extra hour of primetime daylight is supposed to save energy, but the decision to make the extension was based on some questionable numbers. And any subsequent statistical support is a long way off. "The jury is still out on the potential national energy savings," says U.S. energy department spokeswoman Megan Barnett.

Congressional sponsors of the bill in 2005 argued that starting daylight time the second Sunday in March and ending it the first Sunday in November would cut electricity usage. Natural light would substitute for electric lights and people would participate in electricity-free outdoor activities instead of heading home to use appliances and watch television.

When Edward Markey, a Massachusetts Democrat, and Fred Upton, a Michigan Republican, introduced the bill, they said the extension could save Americans the equivalent of 100,000 barrels of oil a day -- an estimate repeated frequently in the media. But that statistic relied on figures from 1974, when President Nixon sprung clocks forward early, in January, during an energy crisis.