Brazil’s renewable curtailment reaches 73.4 million MWh since 2021, financial impact estimated up to R$13.6 billion

Volt Robotics analysis identified 51 critical days between January and August 2026 when more than 60% of available renewable generation was restricted at some point, with 12 days reaching 80% curtailment. The frequency marks a sharp increase from 30 critical days in the same period of 2025, when only seven reached 80%. Average curtailed volume climbed 18.3% year-on-year to 3,853 MW, equivalent to 22.47 billion kWh that could have powered approximately 15.6 million residences for eight months, roughly matching total residential units in São Paulo, Rio de Janeiro and Fortaleza combined.

From October 2021 through August 2026, the Curtailment Tracker logged at least 73.4 million MWh of cut generation across all restriction categories and analyzed plants. Volt Robotics estimates the economic impact between R$8.6 billion using spot market pricing and R$13.1 billion when applying individual contract modeling without monetary correction. Under adjusted scenarios accounting for data revisions, curtailed volume could reach 75.8 million MWh valued up to R$9 billion by spot pricing or R$13.6 billion by contract methodology. The discrepancy highlights uncertainty around measurement criteria and economic valuation methods.

The composition of curtailment shifted significantly, with energy-related cuts (excess generation versus demand) accounting for 67% in 2026 compared to 49% in 2025 and 21% in 2024. The remaining categories comprise electrical restrictions from transmission line unavailability and reliability constraints when available network capacity cannot evacuate all renewable output without compromising system security. Volt Robotics emphasizes that regulatory classification does not always identify root causes. Two 2025 Sunday episodes illustrate divergent triggers for similar curtailment levels: August 10 saw near-100% cuts driven by demand 15% below forecast while 13 GW of thermal generation remained online, whereas May 4 reached 95% under different demand and thermal dispatch combinations.

The study warns curtailment has evolved from a commercial loss mechanism to evidence of declining system maneuver room. When nearly all controllable solar and wind generation is already cut, few resources remain to respond to further demand drops, forecast deviations or grid element failures. The Ministry of Mines and Energy’s Portaria 140/2026 establishes compensation for reliability-related cuts between September 2023 and November 2025, estimated at R$4.4 billion using contract valuation and covering 21.8 million MWh. Wind plants account for approximately R$3.4 billion and 17 million MWh, solar for R$963 million and 4.8 million MWh.