For almost five decades, the French have gotten into the habit of moving their clocks forward and back twice a year. But does this still make sense?
In 2024, the Easter weekend is marked by two events: the egg hunt and the time change. If the first is clearly the most important, the second will have an impact on our night’s sleep and on the debates that will take place at aperitif time.
Fortunately, the Clubic editorial team is here to enlighten you on the subject and help you shine in society.
Yes, moving your watch forward one hour saves energy.
In France, the change in summer time was relaunched in 1976, following the first oil shock of 1973. Electricity being largely produced by heavy fuel oil power plants, all clocks are moved forward by one hour on the last Sunday in March. saved a substantial amount of oil.
According to estimates at the time, the energy savings would have been 450 GWh per year. Two decades later, in 1995, a new study was carried out, and this figure was estimated at 1,200 GWh, with the French consuming more electricity. However, in the meantime, technologies and uses have evolved, data that the report had not taken into account, which made its results out of step with the reality of the 90s.
The last study on the subject dates back to 2010 and was commissioned by ADEME. At the time, the agency concluded that the time change saved 440 GWh per year, taking into account only the electricity consumed by lighting. At the same time, it estimated that this generated 44,000 tonnes less CO2, the energy produced at night being more carbon-intensive than that produced during the day.
A habit that could well disappear
ADEME also ventured to predict the benefits of time change over the next two decades. With the adoption of more energy-efficient lighting technologies, the French could consume up to 340 GWh less each year by 2030 thanks to summer time. In terms of air conditioning and heating, the latter would “save” 130 GWh of electricity. An estimate that will not age very well, with climate change having more and more impact on our daily lives.
So, is the economy really important? To give you an idea, in 2023, France consumed on average 1,220 GWh of electricity per day. We therefore let you judge the merits of the approach. However, for ADEME, any saving is a good thing, especially since the cost of implementing the time change is, according to the agency, almost zero.
Numerous studies have attempted to uncover the impacts of this practice on stock markets or even on human health. Their results tend to contradict each other and there is ultimately no scientific consensus on these questions. Finally, the only point on which everyone agrees remains the evaluation of the savings generated: they are minimal. According to a 2017 meta-analysis of 44 studies, electricity consumption is reduced, on average, by only 0.3% per day in territories where daylight saving time applies.
An observation corroborated by the European Parliament in a report published the same year, which then mentioned a “ marginal effect in terms of energy saving », notes Capital. It is this conclusion which motivated the end of the time change in the EU from 2021. Three years later, this new policy has still not come into force, and for good reason: the major events of The 2020s, like the Covid-19 pandemic, have somewhat relegated this type of project to the background.
Before sharing this new knowledge with those around you, there is one last thing you need to know to become an expert in the field. This Sunday, you will indeed have to set your clocks forward by one hour. Or, in language that everyone understands: you will sleep an hour less.
Source : ADEME, Capital, Sage Journals, Vie-publique.fr
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