From January 1 to October 28, 2026, 70.0% of Brazil's wind and solar curtailment was for energy reasons (ENE, oversupply: 23.67 TWh), 19.1% for electrical reliability (CNF: 6.45 TWh) and 10.9% for external grid unavailability (REL: 3.70 TWh); per-cluster curtailment gated by restriction reason (curtailment ordered by ONS) plus the estimate for plants without data, the Curtômetro counter's yardstick; source: ONS open data, read by BrazilGrid.
Curtailment is not energy generated and thrown away: it is potential output that never happened. ONS estimates how much each plant could generate with the wind or sun of the moment (reference generation) and, for energy, reliability or grid reasons, orders it to generate less; the difference is the curtailment.
| Reason | Wind 2026 | Solar 2026 | Total 2026 | % of 2026 | Last 12 months | Compensable? |
|---|---|---|---|---|---|---|
| ENE — Energy (oversupply) | 13,851.1 | 9,814.9 | 23,666.0 | 70.0% | 27,694.6 | No. Article 1-B of Law 10,848/2004 (added by Law 15,269/2025) covers only REL and CNF, and the Commitment Term excludes oversupply. |
| CNF — Electrical reliability | 5,763.5 | 685.6 | 6,449.0 | 19.1% | 8,574.2 | Ordinary regime: no. Law 15,269/2025 (art. 1-B): yes, under the same conditions as REL; claim currently suspended by an ANEEL injunction (Order 148 of 2026-01-20, extended on 2026-05-13). |
| REL — External grid unavailability | 2,888.3 | 807.1 | 3,695.4 | 10.9% | 3,906.6 | Ordinary regime: yes, above the annual hour allowance (ANEEL Resolution 1,030/2022, arts. 16 and 20-D). Law 15,269/2025 (art. 1-B): yes, without allowance, for events from 2023-09-01 to 2025-11-25, through a Commitment Term. |
| Total | 22,503.0 | 11,307.5 | 33,810.5 | 100.0% | 40,175.4 |
ONS data carries only three reasons: ENE, CNF and REL. Regulatory text reviewed on 2026-10-24; legal basis in force: ANEEL Normative Resolution 1,030/2022 (consolidated text).
From January 1 to October 28, 2026, 70.0% of Brazil's wind and solar curtailment was for energy reasons (ENE, oversupply: 23.67 TWh), 19.1% for electrical reliability (CNF: 6.45 TWh) and 10.9% for external grid unavailability (REL: 3.70 TWh); per-cluster curtailment gated by restriction reason (curtailment ordered by ONS) plus the estimate for plants without data, the Curtômetro counter's yardstick; source: ONS open data, read by BrazilGrid.
They are the reasons ONS records for a restriction: ENE is energy (supply exceeding load), CNF is system electrical reliability and REL is external grid unavailability (transmission equipment out of service).
Under the ordinary regime, only REL above the annual hour allowance (ANEEL Resolution 1,030/2022, arts. 16 and 20-D). Law 15,269/2025 (art. 1-B) created compensation for REL and CNF for events from 2023-09-01 to 2025-11-25, through a Commitment Term, currently suspended by an ANEEL injunction. ENE (oversupply) is not compensated.
ANEEL Resolution 1,030/2022 sets a base of 78 hours per year for wind and 30.5 hours for solar (arts. 16 §2 and 20-D §2), updated yearly by ONS. The value applied in 2026, published by ONS (2021/2025 cycle), is 110 hours for wind and 55 hours for solar, accumulated from the start of the calendar year.
Updated 2026-10-29 15:29 (Brasília time, UTC-3) with data through 2026-10-28. Primary source: ONS open data (dados.ons.org.br); BrazilGrid reads and consolidates.