Tim Haab of Environmental Economics on daylight savings time:
Are Daylight Savings Time Energy Savings a Myth?, by Tim Haab: This year, The U.S. has decided to extend daylight savings time with the intent of saving energy--an anticipated 1% decrease in electricity consumption. A recent study out of Berkeley claims such claims are wrong. Here's the abstract:
Rising energy prices and environmental concerns are driving countries to consider extending Daylight Saving Time (DST) in order to conserve energy. ... In this paper we question the findings of prior DST studies, which often rely on simulation models and extrapolation rather than empirical evidence. By contrast, our research exploits a quasi-experiment, in which parts of Australia extended DST by two months to facilitate the Sydney Olympic Games in 2000. Using detailed panel data on half-hourly electricity consumption, prices, and weather conditions, we show that the extension failed to reduce electricity demand. We further examine prior DST studies and find that the most sophisticated simulation model available in the literature significantly overstates electricity savings when it is applied to the Australian data. These results suggest that current plans and proposals to extend DST will fail to conserve energy.
To be clear, I should note that this study is about whether the incremental change in DST saves energy (e.g. moving it back three weeks), not whether it saves energy overall. This letter to the editor explains the issue:
Besides affecting the mood of many people, of which I am one, how does daylight saving time (and using electricity for an extra hour in the morning) cut usage? Consuming less at night but more in the morning does not save electric power. Dark is dark no matter when it comes. -- Robert D. Hartzfeld, Van Nuys
In mid-summer, when it's lighter and warmer when most people get up, the equation is different.