Enel has accused Brazil’s federal electricity regulator of distorting performance data and applying nonbinding standards in a case that could strip the company of its power distribution concession in metropolitan São Paulo, the country’s largest electricity market.
In a new filing submitted Thursday, the Italian-controlled utility challenged the basis of an administrative proceeding opened by Aneel, Brazil’s National Electric Energy Agency, in April. The regulator’s board had recommended moving toward “caducidade,” a formal termination of the concession contract, after a series of major blackouts in São Paulo.
According to Folha de S.Paulo, Enel argues that Aneel relied on a performance benchmark that was never formally adopted as a binding rule: the restoration of electricity to 80% of affected consumers within 24 hours after severe weather events. The company says the benchmark originated as a technical suggestion in 2024 and that Aneel’s own board recognized in April 2026 that there was no consensus on the metric.
The dispute centers in part on a Dec. 10, 2025 storm that left 4.2 million customers without power in São Paulo and surrounding cities. Wind gusts reached 98 km/h, damaging the grid through falling trees and debris. Aneel concluded that Enel restored service to only 67% of customers within the first 24 hours.
Enel disputes that figure. The utility says Aneel used a “simultaneous peak” method, which measures the moment of maximum interruption, even though the agency had previously rejected that approach in technical notes. Enel says the correct standard is the “total duration” of interruptions. Under that method, it says its 24-hour restoration rate was 80.2%, just above the threshold considered satisfactory by inspectors.
The company also argues that the December storm should be treated as force majeure under Brazil’s Concessions Law, which states that service interruptions during emergencies do not constitute discontinuity. Enel described the event as the longest windstorm in 19 years, with gusts lasting for 12 consecutive hours, and said no electricity network would be immune to weather of that scale.
São Paulo’s power reliability problems have become a major political issue since a severe storm in November 2023 left millions without electricity for days. Another major outage followed in September 2025, when 900,000 customers lost power after winds of 98.2 km/h. Enel says Aneel gave excessive weight to the December 2025 blackout while ignoring what it described as steady improvement over 16 months, with restoration rates between 93% and 100% in most monitored storms from November 2024 to March 2026.
The utility also accused the regulator of unequal treatment, comparing its case with that of Copel, the power distributor in Paraná state. Enel says Copel had worse operational performance during a severe weather event in September 2025, with some customers left without power for 207 hours, but Aneel still considered its response satisfactory.
The case is unfolding under pressure from local politicians. São Paulo Mayor Ricardo Nunes, of the centrist MDB party, and Governor Tarcísio de Freitas, a conservative ally of former President Jair Bolsonaro, have both called for the end of Enel’s contract, arguing that the service is inadequate. The city government and Enel are also locked in a dispute over tree pruning, a recurring factor in storm-related outages.
Aneel must now review Enel’s defense. If the agency maintains its recommendation, the case will move to the Ministry of Mines and Energy, with the final decision resting with the federal government. Specialists cited by Folha estimate that terminating the concession could require compensation of about R$15 billion for investments in the grid that have not yet been amortized.
Enel serves 8.5 million customers in metropolitan São Paulo. The company is asking Aneel to cancel the order that opened the termination process, close the case and resume analysis of its concession renewal. If the administrative decision goes against the utility, the dispute is likely to move to the courts.
This article is based on single-source reporting from Folha de S.Paulo.