Saturday midnight (16) to Sunday (17) daylight savings time ends in Brazil. Since November 4th, 2018, residents of 10 States (see list at the end of note) and the Federal District had their clocks forward 1 hour in relation to the rest of the country. This Sunday, these people turn their clocks back 1 hour. 

What is daylight savings time for? 

In Brazil, daylight savings time was adopted for the first time in October 1931, per a decree signed by then-president Getúlio Vargas, which became effective in March 1932, and was revoked the following year. In the Federal Constitution of 1942, an article stated that “the Federal Government is the sole responsible to govern on water, energy, information technology, (and) broadcasting”, giving an opportunity to “measures related to consumption reduction.” Since then, daylight savings time has been on and off Brazil’s calendar. However, this measure has been kept uninterruptedly since 1985.

Currently, daylight savings time starts at midnight on the first Sunday of November, lasting until midnight of the third Sunday of February of the following year – if daylight savings time last Sunday and carnival Sunday coincide, it ends the following Sunday. During this period, clocks are set forward one hour. 

Daylight savings time runs in the states of Espírito Santo, Goiás, Mato Grosso, Mato Grosso do Sul, Minas Gerais, Paraná, Rio de Janeiro, Rio Grande do Sul, Santa Catarina, São Paulo, and the Federal District.

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Where else does DST run?

According to the Ministry of Mines and Energy (MME), some studies show that the first daylight savings time experience came to life in the USA, adopted by then North American president Benjamin Franklin, in 1784 – the reason, at the time, was to give residents more leisure time under daylight. This measure was consolidated in North American territory in 1918.

Today, most countries with daylight savings time are located beyond a circle of latitude 30°, northward or southward – Brazil is one of the few countries in tropical regions that adopts this measure. Countries like Canada, Australia, Greenland, Mexico, New Zealand, Chile, Paraguay and Uruguay run daylight savings time.

Why was daylight savings time created?

The main purpose of daylight savings time is to take advantage of daylight more efficiently, since it doesn’t consume electric power. Thus, to lower the concentration of electricity consumption between 06:00 pm and 09:00 pm, clocks are set forward one hour. The Ministry of Mines and Energy explains that the rationale behind this measure is to drive “flattening of the consumption curve,” reducing electricity peak levels during this period. Hence, between 06:00 pm and 09:00 pm, consumption would remain at low levels, with less load in overhead power lines, in substations and grid supply. 

The main reason for this load peak is the coincidence between street lighting, at sunset, and turning on showers at households – The average behavior of Brazilians shows that they shower at these hours.

The duration of daylight savings time was established by technical criteria that shows the optimal way to leverage light differences between summer and other seasons. Studies show that, historically, daylight savings time is more efficient in regions away from the equator, where the difference of light between summer and other seasons is less significant. That is why Brazil’s Northern regions do not change their clocks.

Why may DST come to an end?

In the second half of 2016, the Energy Secretariat of MME and the Operator of the National Electricity System (ONS) started to investigate the results of daylight savings time deeply, from an electric system perspective. The conclusion, presented in August 2017, was that “the application of this public policy currently brings results close to neutrality for the average Brazilian electric power consumer.”

Justification lies in the change of habits and possessions of the Brazilian consumer. In the past few years, the increase in the profile of the electrical load curve has been strongly associated with a higher amount of climatization equipment (especially, air conditioning devices). In this sense, the applied methodology must necessarily consider temperature as an explanatory variable – and not just the incidence of daylight.

Hence, there was a transfer of maximum daily electricity demand to daytime, resulting in neutrality for a decrease in consumption – some methodologies even show a marginal increase in electrical load due to daylight savings time. Today, electric power peak happens between 02:00 pm and 04:00 pm, a result of temperature rise and, consequently, more intense use of air conditioners.

Some methodologies even show a marginal increase in electrical load due to daylight savings time.

What will happen to daylight savings time?

Also in 2017, Technical Note No. 4/2017/CGDE/DMSE/SEE, elaborated by MME jointly with ONS and sent to the Staff of the Presidency of the Republic, states that DST “is no longer justifiable by the electrical sector.” MME further claims that, for the electrical sector, “regulation instruments for economic signaling differentiated by time, like the white tariff and per hour rate, may yield more relevant results.”

Evaluation of DST results takes place annually. With the end of the 2019/2020 cycle, there will be a new study of electrical efficiency on the measure, which will again be submitted to the Civil House. 

It’s up to the Presidency of the Republic to decide whether to maintain or terminate daylight savings time. Given that this decision doesn’t impact only the electrical sector, but also economic results and public health indexes, it needs extensive analysis.

For the Brazilian Association of Electricity Distributors (Abradee), from an energy perspective, in fact, daylight savings time doesn’t have significant results anymore. Technical reports show us that the effect is increasingly attenuated due to the transfer of load time. “Today, it’s possible to attenuate this load point by expanding power generation with sources such as solar and wind or power efficiency measures,” says Nelson Leite, president of the body.

Bluevision reached out to the Civil House press office, which has not commented on DST’s maintenance or termination up to date.

Content published in February 19, 2019