ONS evaluates return of daylight saving time to avoid blackouts

Brazil may return to daylight saving time this year. The National Electric System Operator (ONS) raised the possibility if projections indicate that power supplies will remain tight during peak hours, between 6 and 8 p.m., when the system faces greater difficulty balancing generation and consumption. Daylight saving time was suspended in 2019 by the Jair Bolsonaro (PL) administration.

The final decision on whether or not to adopt daylight saving time lies with the President of the Republic, based on technical information from the ONS and the Electricity Sector Monitoring Committee (CMSE).

The Energy Operation Plan (PEN) for the period between 2025 and 2029, released Tuesday (8), revealed that the power deficit, a problem already identified in previous years, is intensifying, requiring urgent measures to avoid blackouts and maintain supply stability.

One of the factors contributing to this situation is the rapid increase in solar generation, both centralized and through micro and mini distributed generation (MMGD). Although this expansion increases the country's installed capacity, it fails to meet peak-hour demand, precisely because this period begins after 6 p.m., when solar production ceases and most of the population is at home. This mismatch between supply and demand makes it essential to contract energy sources that can be activated quickly, such as hydroelectric and thermoelectric plants.

The ONS document indicates that, in the second half of 2025, especially during the dry season, the increased use of thermal power plants will be inevitable, which increases operating costs and, consequently, the end consumer's electricity bill and pushes inflation up.

This was the scenario that put the ONS on alert and forced it to consider the possibility of suggesting the return of daylight saving time, as an emergency strategy to redistribute consumption and alleviate pressure on the system during the most critical times.

ONS: even with daylight saving time, other actions are necessary

The ONS reinforces the importance of holding annual auctions to contract power, prioritizing flexible sources that can respond quickly to fluctuations in demand and intermittent renewable generation. Other strategies include bringing forward the start-up of contracted thermal plants and importing energy from neighboring countries to cover potential deficits.

ONS Director-General Márcio Rea emphasizes that operational flexibility is essential to ensure the security of the electrical system in the face of changes in the energy matrix. "The balance between supply and demand, especially during so-called load ramps—periods of rapid variation in consumption—increasingly depends on the agile response capacity of controllable sources," he explains.