Brazil could face a growth of up to 300% in renewable energy generation cuts — known as curtailment — by 2035. The estimate is part of an analysis by international consultancy Wood Mackenzie, which warns of the risks of accelerated expansion of solar and wind sources without proper monitoring of the electrical infrastructure.
The country is projected to add 76 GW in new renewable power plants over the next ten years. However, this growth has not been accompanied by the same pace of expansion of the electricity grid, which creates limitations in the flow of energy generated, especially at peak times.
According to the consultancy, the average curtailment rate in the SIN (National Interconnected System) could jump from the current 2% to 8% by 2035. In the Northeast, a region that concentrates a large part of the country's solar and wind generation, the scenario is even more worrying: the forecast is an average curtailment of 11%, while in the Southeast and Central-West the estimated rate is 2%.
Although there are plans to reinforce the transmission grid — with the expectation that capacity between the Northeast and Southeast will exceed 30 GW by 2035 — expanding the grid alone is unlikely to solve the problem.
Marina Azevedo, a senior analyst at Wood Mackenzie, points out that even with 11 GW of lines planned by 2029, curtailment is expected to continue growing. According to her, the Brazilian electrical system has not been able to keep up with the speed of renewable energy expansion, especially during peak solar generation times, between 8 am and 17 pm.
This concern was recently reinforced by the executive advisor of the ONS (National System Operator), Sumara Tigon, in an interview with Canal Solar during the Greener Summit 2025. At the time, she warned that the current model is not sustainable and that, if nothing is done, not even centralized generation will be able to balance the system.
Sumara also stressed that the problem can no longer be attributed solely to transmission, as it has become largely an energy issue rather than a reliability issue.
Storage
Wood Mackenzie’s study reinforces that without energy storage and other flexibility resources, such as demand response, generation cuts will continue to rise. “Storage is no longer an option. It will be essential to transform energy that would currently be wasted into revenue through price arbitrage and network services,” says Fernando Dorand, an analyst at the consultancy.
This understanding is shared by the ONS itself. In its most recent technical report on the subject, the Operator reinforces that the expansion of REDs (Distributed Energy Resources) is essential to maintain the stability of the SIN. However, the ONS also warns that, without a modernization of the rules and greater participation of distributed agents in the control of the system, the risk of blackouts becomes more and more real.
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