Brazil curtailment expected to remain elevated through 2027

Power generation curtailmentin Brazil is expected to remain high until 2027, due to the mismatch between the expansion of renewable generation, the growth in consumption (load), and the expansion of transmission.

The assessment is by Pedro Moro, pricing and market studies manager at the local consultancy Thymos Energia.

He emphasized that, on average, the cuts went from approximately 3.6% of total generation (realized and unrealized) in 2023 to 9.4% in 2024 and 20.7% in 2025.

"For 2026, our expectation is that curtailment will remain at a high level, and may even be above what was observed in 2025, still reflecting the combination of strong renewable expansion in recent years, transmission constraints, and comfortable storage levels in the reservoirs," Moro told BNamericas.

For 2027 onwards, the consultant foresees a gradual reduction in the energy surplus and, consequently, in curtailment, thanks to the slowdown in renewable expansion, the growth in load, the entry of energy storage systems into the system, and new transmission reinforcements.

According to data from the National Electric System Operator (ONS), the ungenerated output (GNR) between January and May 2026 totaled 3.007MW on average, representing 17.7% of the total. In the same period in 2025, curtailment was 2.614MW on average, accounting for 15% of the total. Over the whole of last year, ungenerated output was 4.248MW on average. 

This year, wind and solar power plants accounted for 63% (1.898MW average) and 37% (1.109MW average), respectively, of the unperformed generation, compared with 65% (1.715MW average) and 35% (899MW average) in 2025.

Most of the curtailment between January and May 2026 (1.985MW average) occurred for energy reasons, when supply exceeds demand. In the same period in 2025, it was 1.091MW on average for the same reason. 

Another 598MW average were cut due to reliability issues – aiming to preserve the stability of the power grid and avoid blackouts or overloads –, versus 587MW average one year earlier. 

The remaining 423 average MW in this year’s curtailment account were driven by external unavailability (compared to 983 average MW in 2025), which occurs when the ONS reduces or interrupts a plant’s generation due to failures or maintenance in the power transmission grid.

(The original version of this content was written in Portuguese)