Twice a year, a familiar change is carried out — the clocks are advanced by one hour in the spring to mark the beginning of Daylight Saving Time (DST) and then back by one hour in the autumn to bring it to an end.
Among other aims, DST is designed to meet energy savings goals. Under Law 34/2023, DST is applied in Egypt on an annual basis, commencing on the last Friday of April and continuing until the last Thursday of October.
According to engineer Mamdouh Abdel-Karim, “electricity companies manage the grid according to what is known as the ‘load curve’ that illustrates patterns of energy consumption over a 24-hour period. Peak consumption times, particularly during the summer months, occur immediately after sunset, resulting in extra hours of artificial light and the waste of natural daylight.”
DST is designed to reduce energy consumption by making use of that otherwise wasted natural daylight.
“Some people may assume that a single hour makes little difference. However, the concept is grounded in what may be described as a ‘law of scale’ that does not concern a single individual, but rather millions of households, lighting units, and electrical appliances across public institutions and commercial centres. When the clock is advanced, what occurs is referred to as ‘load shifting’. By moving the time forward, people complete their work and return home during daylight hours,” Abdel-Karim said.
During the 1980s and 1990s, the consumption patterns of Egyptian households were relatively simple and predictable.
“Traditional lamps consumed most of their energy as heat, and a single television set gathered the family around it. However, today the situation has completely changed. With the population exceeding 110 million, consumption is no longer linked to the household as a whole, but rather each individual has become an independent point of consumption through the use of mobile phones, computers, and smart watches, in addition to devices that operate continuously, such as routers,” Abdel-Karim said.
“These devices have significantly increased the base load on the electricity network, even during the late-night hours that were once considered as a period of rest for the grid. Thus, the application of DST is essential” to saving energy at scale.
DST was first suggested by the American writer Benjamin Franklin in 1784. In a satirical essay titled “An Economical Project for Diminishing the Cost of Light”, he proposed economising on the use of candles by rising earlier to make use of the morning sunlight.
However, the system did not take its current form until 1907, when the English businessman William Willett campaigned for legislation to be enacted. The idea was later applied during World War I, when Germany advanced its clocks to save energy, and many other countries followed until the end of the War. It was reintroduced again during World War II, only to be abolished shortly afterwards. Later, its use became widespread due to the belief that it helped conserve energy.
Mohamed Hafez, an economist, said that “the implementation of DST and early shop closing hours are not merely administrative measures. They are designed to send a message aimed at reshaping behaviour.”
“The American-Israeli war on Iran and its impact on the Strait of Hormuz, alongside the disruption of nearly 20 per cent of global oil transit, represents a kind of blockage in the aortic artery of the global energy that supplies factories, households, and transport. Egypt is not isolated from this shock,” he added.
Prime Minister Mustafa Madbouli has announced that Egypt’s monthly natural gas import bill has surged from approximately $560 million before the outbreak of the war to $1.65 billion today.
The price of Brent crude oil has escalated from $69 per barrel before the conflict to a range of $93 to $103 recently. It then declined $87 before rising again to $108.5 per barrel. Diesel prices have also increased from $665 to $1,604 per ton. Liquefied natural gas (LNG) prices have risen from $510 to between $720 and $730 per ton, representing an increase of about 33 to 34 per cent.
“The situation places a heavy burden on the state, and the adoption of DST, along with the system of closing shops and commercial establishments at 11 pm, is aimed at bringing some temporary relief to the crisis,” Hafez said.
Despite their potential impact on such outlets, the measures are becoming a necessity, he added, saying that “even if just one watt of electricity is saved, this still represents a real contribution to reducing the demand for the foreign currency required to import LNG.”
“The longer daily hours increase outdoor activities and increase productivity, leading to economic growth. Globally, 75 countries currently apply DST, including 49 countries in Europe,” Hafez said.
HISTORY: In Egypt, DST was first adopted during the government of then prime minister Mahmoud Fahmi Al-Nokrashi in 1945 owing to the pressures of World War II and the rise in fuel prices.
The system was stopped under Law 87/1975 but brought back in 1982 during the rule of former president Hosni Mubarak. It was cancelled again in 1985 before being re-introduced by Law 141/1988, with an exception for the month of Ramadan.
Following the 25 January Revolution in 2011, the Supreme Council of the Armed Forces (SCAF) suspended the use of DST in response to public demands. In 2014, it was temporarily brought back under interim president Adli Mansour due to the energy crisis. It was definitively reinstated under the current 2023 law.
Lawyer Gamal Al-Sayagh said that “parliament, throughout all these phases, has adopted what is suitable for each period. The application of DST is seen as a reflection of the current economic phase, and though most people remember to adjust their clocks, it can still cause confusion.”
Differences in DST schedules between trading partners can potentially influence exchange rates and international trade, causing disruption in international contracts, flight schedules, and trade movements. If a vessel arrives at a time that has shifted due to DST, legal disputes may arise over whether the delays are due to force majeure or carrier error.
In aviation, the issue is more precise, as flight schedules are governed by strict global timing systems. Airlines are expected to be fully prepared for such adjustments. Any timing error can create operational confusion, and in cases of delay, changes in clock time are not usually accepted as valid excuses, Al-Sayagh said.
“I advise everyone in business to exercise caution and ensure careful coordination in order to avoid unnecessary disruption,” he said. “With proper planning and anticipation, such risks can be better managed and controlled.”
Different parts of the world are differently directly affected by climatic conditions and behavioural patterns. While Franklin’s original argument on lighting still has some relevance, the more significant impact of DST today is linked to air-conditioning systems.
Ehab Al-Morshedi, a sustainable development consultant, explained that “many historical discussions surrounding DST focused on reducing electricity consumption through a decreased reliance on artificial lighting. But this argument no longer accounts for present-day realities, and in some cases it may even result in an increase in electricity consumption rather than a reduction.”
The major source of carbon emissions in buildings comes from their energy usage, which makes it necessary to decrease building heating and cooling requirements to contribute to climate-change mitigation. The energy requirements for heating and cooling systems are determined by various elements that include a building’s design and the materials used in its construction and environmental conditions and patterns of use.
Climate change will bring about new weather patterns that will likely result in increased temperatures and more frequent heat waves. Office buildings demonstrate this effect more clearly than residential buildings because they require additional cooling capacity due to their larger windows and higher occupancy levels and their equipment systems that create extra heat.
Al-Morshedi said that “priority should be given to the type of energy demand that is harder to meet through sustainable sources”.
Cooling can often be met more easily using renewable energy such as solar power, for example. In contrast, heating is more difficult to cover, especially in colder periods, using solar energy alone. Location also plays an important role. Access to renewable sources such as wind energy can support more sustainable heating.
Heat pumps can also support this process. However, if reducing heating demand is the more sustainable option, then removing DST may in some cases lead to a greater overall reduction in carbon dioxide emissions than keeping it, Al-Morshedi commented
DST also does not only relate to the organisation of time or the saving of energy. It also has a clear impact on human health. Three time systems regulate our daily lives, including solar time, social time, and our internal biological clock that follows a cycle of around 24 hours and is mainly affected by the amount of light that reaches the eye.
Psychologist Naglaa Shawki said that “light plays a central role in regulating melatonin, the hormone responsible for sleep and waking patterns and that also helps maintain the body’s natural rhythm. Natural light remains the most effective source of this light, as it provides the required quality and quantity. Any sudden shift in time can lead to disturbing this system, as the body needs a period to adjust.”
The effect is not limited to physical health but also extends to mental well-being and daily performance. Some individuals, mostly young adults, may experience reduced concentration and productivity when DST is introduced or removed.
The body must reset its biological clock, and the return to standard time, with shorter daylight hours, may lead in some cases to seasonal depression caused by reduced exposure to sunlight and resulting in low energy and fatigue.
At the same time, DST may have certain positive effects as longer daylight hours can contribute to improvements in mood. Shawki said that “those who are highly affected by changes in the clock should prepare themselves to welcome DST with a positive mindset.”
“Dinner and bedtime should be brought forward, even by as little as half an hour, and such people should also try to wake up slightly earlier than usual. Most importantly, meals should be light, as heavy meals may place strain on the body during sleep.”
“Watching films or using screens in the evening before sleep should be avoided,” he said, “as this may delay the release of melatonin. Instead, it is preferable to engage in calming activities, such as reading a book.”
* A version of this article appears in print in the 23 April, 2026 edition of Al-Ahram Weekly.
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