ONS Activates Emergency Curtailment for Second Time This Year

Overview

• ONS ordered temporary reductions in generation that affected small hydro plants, biomass units and distributor‑connected wind and solar between 11:00 and 13:30 to prevent excess supply from destabilizing the national grid.
• This is the operator’s second emergency activation this year; the first activation requested about 1,000 MW of managed cuts earlier in the year.
• ONS says rapid growth in distributed generation—roughly 50 GW of rooftop and small systems—creates blind spots it cannot directly observe or control, forcing ad hoc curtailment when manual measures and reductions of large hydro and thermal output prove insufficient.
• The distributors’ trade group Abradee warned that ad‑hoc cuts create legal and financial uncertainty for generators and asked for clear, pre‑defined procedures and criteria to govern future curtailments.
• ONS plans a pilot of the automatic Esquema Regional de Alívio de Geração (Erag) by the end of 2026 that would enable three staged cuts of about 1 GW each up to 3 GW total, and the pilot’s outcome will shape a wider rollout and how liability and market impacts are handled.