Daylight Savings Time: Energy Dud?

March 9, 2007 — Now there's one more reason for early risers to groan about Daylight Savings Time: It saves no energy, suggests a new study.

Energy efficiency has long been the argument in favor of "springing ahead" an hour every spring and pushing more daylight into the evening.

But a study measuring actual energy use in Australia with and without Daylight Savings Time (DST) shows that any energy saved in the evenings was more than made up for by more energy needed in the darker early morning hours.

"We think it's a bad idea to use it for energy policy," said Hendrik Wolff of the University of California at Berkeley's Department of Agricultural and Resource Economics. He and Ryan Kellogg published their results in a University of California Energy Institute working paper.

The news comes just as the U.S. federal government institutes DST three weeks earlier — on March 11 — as part of the 2005 Energy Policy Act.

The adjustment was based on simulations that, says Wolff, don't reflect real energy use very well. As a result, DST does not deliver the promised 0.6 to 3.5 percent or so of energy savings. Instead, it may actually raise energy use slightly.

"Our study is the first in a series of studies that contradicts previous studies," Wolff told Discovery News.

In their study, Wolff and Kellogg looked closely at what happened in one of the two states in Australia that stretched out DST by two months to accommodate the 2000 Olympic Games in Sydney.

The researchers broke down energy consumption in the state of Victoria into 30-minute increments and incorporated weather and energy prices. They left out the Olympics themselves and New South Wales, where the Olympics were held.

What they found, in the end, was no energy savings at all.

"We should pull it out of the energy bill," said Wolff. There are better reasons for DST, he said, like lowering crime rates or getting people to exercise more after work.

The Australian results mirror those of an energy use simulation study recently reported by researchers with the California Energy Commission (CEC).

"The simulations examined how electricity use would respond to newly darker and cooler mornings, using cool dark winter mornings as a reference point, and how electricity use would respond to lighter and warmer evenings by looking at those in the summer," reported Adrienne Kandel, of CEC's Electricity & Demand Analysis Division.

In that study, the researchers found that if people maintain their daily schedules, earlier spring and later fall DST extensions would probably cause a two to five percent drop in the evening peak load. Meanwhile, morning electricity use would grow.

"The net effect is small and uncertain. A best guess of total net energy savings is on the order of 1/2 of one percent, but savings could just as well be zero," Kandel reported. "Moreover, our statistical analysis leaves us with one chance in four there could be a very small increase in electricity use."

According to some sources, DST was invented in Germany in World War I. It was first adopted by the U.S. Congress in 1918.