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Does Daylight Savings Time Actually Save Energy?

Spring and Fall clock changes were originally implemented to help save resources by decreasing lighting demands, but over a century later, are they accomplishing those intentions?

The surefire signs that Spring is just around the corner have started to appear – trees are budding, flowers beginning to bloom and there’s more rain than snow. (Full disclosure – I live in the UK now, so if the snow is persisting in Canada, I apologize for the false hope.) Very soon it will be time to move our clocks forward one hour, pushing sunrise to post-7 am, but giving us light until nearly 8 pm.

Daylight saving time (DST) is a hallmark of industrialized societies and has been observed for over a century. But before anyone considered formally adopting clock changes, there were still efforts to capitalize on sunshine. Roman hours were made longer in the summer and shorter in the winter, and in 1784 Benjamin Franklin, then American envoy to France, suggested Parisians could save on candles by waking up earlier, with the sun. The 1810 Spanish Nation Assembly moved certain meeting times forward by one hour from May to September because of daylight, and many businesses simply changed hours to fit daylight patterns.

It wasn’t until 1895 when a New Zealand entomologist, George Hudson, who sought more daylight time after his shift work to look for insects, suggested it to the Wellington Philosophical Society and then wrote an 1898 paper, that formal clock changes were considered. An Englishman named William Willett also proposed similar in 1907, in part to allow him to play golf longer in the evenings.

Port Arthur, Ontario was actually the first place in the world to embrace DST, enacting the clock change in 1908, followed quickly by Orillia, Ontario in 1911. It didn’t gain a broader appeal until 1916 when the German Empire and Austria-Hungary put it into practice. And the ball really got rolling in 1918 with the United States, United Kingdom, its first World War allies and most neutral European nations taking it up. However, when the war ended, most countries abandoned the custom, save for the UK, US, France, Ireland, and Canada.

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WWII saw some return to DST, but it wasn’t until the 1970s energy crisis that most of Europe widely adopted the seasonal clock change. Today you can find DST in most of North America, Europe, New Zealand, some parts of Africa and South America, and, confusingly, part of Australia, including one island that only changes its clocks by 30 minutes. Also confusingly, not everyone changes their times on the same day, leading to a 3-week period where my usual 5-hour time difference to Montreal is just 4.

The timings of DST enactments, during periods of financial and resource tightness, point to its intended purpose: to save energy on lighting. By shifting the clocks so that the sun is up for longer when people are awake, resources – once upon a time, candles and now, electricity – could be saved. The real question is whether it’s effective.

Unfortunately, studies on the energy effects of DST have conflicting results. It’s far from a simple feat to evaluate the energy consumption of an entire country, and results will vary depending on what factors are considered. While Franklin’s idea was for fewer candles to be burnt, our modern lives have far more factors that influence energy consumption. From television to gaming consoles, air conditioning to appliances, we use energy for far more than just lighting now. Even if the electricity used for illumination decreases, many of our other uses of electricity are unlikely to change based on the timing of sunset and sunrise. Also, with more daylight we are more likely to spend time outside our homes, which for many people means driving somewhere, using gasoline in the process.

A 2008 literature review found that simple estimates find a roughly 0.5% decrease in energy because of residential lighting reductions. However, it concludes that if gasoline consumption is considered, the energy-saving effects of DST disappear. A 2018 meta-analysis of 44 studies in various countries found a 0.34% decrease in energy consumption during DST. However, they also mention how the data varied greatly based on the methodology of various studies.

There are many studies of specific regions that show DST saves energy, and just as many, if not more, that show that it doesn’t. A 2017 study of Ontario showed a 1.5% decrease in electricity consumption; a 2010 study of Great Britain found a 0.3% reduction in daily energy demands; and a 2008 study of the United States, a 2016 study of Chile and a 2020 study of Slovakia found comparably small reductions in energy demands.

On the other hand, studies published in 1997 on a house in Kansas and 2011 on Indiana found slight increases in energy consumption during DST.

Studies of places where DST has either been abolished provide natural case studies on its potential energy effects. Turkey abolished DST in 2016, essentially moving to permanent summer time. A study of energy consumption in the country between 2012 and 2020 found that there were no measurable energy savings seen when DST was observed. Argentina observed DST from 1988-2000 and 2007-2009. A study using the hourly energy consumption between 2005 and 2010 found that DST increased total consumption by 0.4-0.6% but decreased peak demand between 2.4 and 2.9%. Jordan began observing DST in 2000 and stopped in 2007. An analysis of energy consumption during this time found a 0.73% reduction in the electricity used for illumination but increases in electricity usage at the times of year DST started and ended.

It’s difficult to draw any conclusions from these studies, in part because it seems that whether DST will save energy depends greatly on the geography and inhabitants of a country. However, even studies showing energy savings show only small ones.

The arguments against DST don't solely rely on false promises of energy savings. Many people find the hour shifts disruptive to their schedules, particularly parents whose kids don't get enough sleep when an hour is lost and must put children to sleep when it’s still light out during the spring. There are also reports that animals find the time changes disruptive. Ironically, a common explanation for DST is that it helps farmers, but when DST was first implemented in the US, farmers largely opposed it, and were one force behind it being repealed in 1919. Modern farmers can be just as opposed, pointing out that light earlier in the day is better for getting work done before the temperature rises.

So, who benefits from DST, if not farmers, and (potentially) not energy producers? For one, businesses. More light in the evenings means more time to shop and spend money. The Association for Convenience and Fuel Retailing, a lobbyist for convenience stores, has pushed to start daylight saving time earlier in the year. Lobbyists from the American golf industry estimated in 1986 that an extra month of daylight saving would be worth between $200 and $400 million USD.

Personally, I like DST. Changing clocks is annoying, it’s true, but I am not an early riser, so I don’t mind a bit of morning darkness. And a mid-March sunset at 7 pm instead of 6 pm feels good for my mental health, especially after enduring a winter of pre-5 pm sunsets. For London, UK, a permanent shift to summer time would mean 2:50 pm sunsets in December while a permanent shift to winter time would mean 3:45 am sunrises. All things considered; I think I’d rather stick with the current system.


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