Brazil has recorded its third consecutive record for renewable energy cuts, according to data from the ONS (National System Operator) analyzed by Volt Robotics.
In October, a total of 5,9 thousand GWh of wind and solar energy was not generated, resulting in a combined loss of R$ 1,1 billion for the generators. In the case of solar energy, the cut was 1,3 thousand GWh, with losses of R$ 192 million.
The total accumulated loss from generation cuts from January to October 2025 – considering the effective value of contracts in the regulated environment – reaches R$5,4 billion.
Since the data became available in 2021, the cost of curtailment totals R$ 8,1 billion. This situation is seen as a crisis that jeopardizes Brazil's energy transition.
"This level of waste is unsustainable, both physically and economically," said Donato Filho, CEO of Volt Robotics, during a press conference held on Wednesday morning.
The all-time curtailment record in October totaled 7.997 MWmed. Looking ahead, between January and October 2025, 20,4% of all possible wind and solar power generation was discarded.
This index is 283% higher (more than triple) than that recorded for the entire year of 2024 and is equivalent to 10,1% of Brazil's total consumption in the month in question.
Impact on solar power generation
Solar power plants were severely affected by the problem. Although the cuts were mainly concentrated in wind power, solar accounted for a significant portion of the total.
Of the 7.997 MWmed cut in October, 1.710 MWmed corresponded to solar power plants, which is equivalent to 21,4% of the total curtailment volume.
In comparison, the generation from Brazil's largest hydroelectric plant – the national portion of Itaipu – totaled 4.587 MWmed in October. Therefore, the cuts in renewable generation were 74% greater than Itaipu's generation during the analyzed period.
The restrictions were concentrated in Rio Grande do Norte, Ceará, and Minas Gerais, the state most affected with a cut of 30,8%.
At the level of individual power plants, distortions in the impacts were observed, with some sets suffering cuts that reached 237 MWmed, which represented 55% of the generation potential of some units in October.
Cuts occur during the day.
The hourly profile of average generation cuts resembles that of solar generation, with the highest values occurring during the day, specifically between 9 am and 16 pm. At times, the cuts reached up to 38.000 MWmed. The predominance occurs during the mornings, when solar generation is most intense.
The main cause of waste in October was lack of consumption, classified by the ONS (National System Operator) as Energy Ratio (ENE). Last month, 50% of the renewable energy cut off was due to this reason. This predominance of excess energy in the mornings is one of the "two daily curses" that lead to the unsustainable situation, noted Donato Filho.
The problem exists, according to the CEO of Volt Robotics, because the generation system has grown rapidly, with a very accelerated expansion of the supply of renewable energy, especially solar.
However, the planning, operation, and regulation of the sector have not kept pace with this progress, resulting in a significant supply of energy in the morning that cannot be utilized due to a lack of transmission network or insufficient consumption.
Batteries as part of the solution
During the press conference, Donato Filho positively assessed the provisions of Provisional Measure 1.304, which deal with curtailment. According to him, the text of the MP represents the first concrete step towards the effective mitigation of cuts, creating mechanisms for financial compensation and more transparent rules for investigating restriction events.
Donato highlighted that the measure acknowledges the external and involuntary nature of the outages, stipulating that businesses affected by reliability issues or electrical restrictions will be compensated via ESS (System Service Charge), with costs shared equally among consumers. Outages due to oversupply—when generation exceeds demand—remain the responsibility of the generators themselves.
From 2026 to 2027, the director of Volt Robotics estimates that the sector will still suffer considerably from curtailment. He believes that an initial relief, even due to structural issues, may occur between 2028 and 2029. However, to solve the problem, the estimate extends over approximately 10 years.
In addition to the reimbursement, Donato highlighted another key point of the Provisional Measure, which deals with the inclusion of energy storage systems as a complementary mitigation tool.
He explained that batteries and other technological solutions could help absorb surplus renewable energy during off-peak hours and return it to the grid during peak demand, reducing the need for power outages.
The expert also offered a forward-looking analysis of the issue. In the short term, he predicts that the reimbursements will help to "stem the financial suffering" of the generators.
In the medium term, it is predicted that the expansion of transmission infrastructure and the integration of storage systems will reduce curtailment volumes.
In the long term, he believes the country will move towards dynamic network management, with intensive use of digital technologies and greater coordination between the National System Operator (ONS). ANEEL and generators.
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