General
Today we know that the switch to daylight saving time does not result in any noticeable energy savings. According to the Federal Association of Energy and Water Management (BDEW), although we consume less electricity for lighting on sunny summer evenings, we consequently use more electricity for our evening leisure activities or for longer running air conditioning systems. Additionally, more and more energy-saving lamps are being used in German households nowadays, leading to a continuous decline in electricity consumption for lighting.
Historical Development
The introduction of daylight saving time has always been associated with the hope of reducing energy consumption.
Benjamin Franklin already formulated the idea of reducing the energy consumption caused by the use of artificial light in the evenings and at night by shifting the daily rhythm forward.
Daylight saving time was introduced in Germany and other countries during the time of the First World War with the aim of saving energy, which was intended to benefit the war economy. Shortly after the war, it was mostly abolished. In the following period, there were only limited attempts with daylight saving time in individual countries until the outbreak of the Second World War when Germany reintroduced daylight saving time, again hoping to save energy. After this war, daylight saving time was abolished in most countries.
The next major impulse for the use of daylight saving time was the oil crisis of the 70s. France reintroduced daylight saving time in 1976. Subsequently, most central European countries followed with some delay - Germany in 1980. The decisive factor here was not so much considerations regarding energy consumption but rather the desire to achieve a harmonized regulation between the individual European countries in order to avoid obstacles to the growing internal market. Finally, in 1996, the regulations for daylight saving time within the EU were fully harmonized with each other.
Actual Effects on Energy Consumption
The postulated reduction in energy consumption through a time change has always been controversial and could never be proven.
Since energy consumption depends on a variety of factors, only a very small effect would have been expected. In fact, daylight saving time seems to even favor increased energy consumption.
While a time change can actually lead to less use of artificial lighting, this is usually offset by an increased consumption of heating energy caused by the advancement of the main heating time. Additionally, the use of energy by increased use of air conditioning in the summer, resulting from the longer days, as well as increased consumption due to leisure activities, nullifies the effect of the lower use of artificial lighting. This effect is amplified in recent times due to the dramatically decreased energy consumption of modern light sources such as LEDs.