Brazil’s planned first auction for utility‑scale battery storage is encountering resistance over a fundamental question of cost allocation. According to Folha de S.Paulo, the auction, which aims to procure capacity reserves to bolster grid security, is currently in the public consultation phase for its edital. Yet many stakeholders already consider a delay all but certain.
Background on the auction
The battery storage auction was introduced by a 2025 law that earmarks the expenses of contracted batteries exclusively to electricity generators, not to the general system where costs would be passed to consumers via tariffs. The government envisions the auctions as a tool to mitigate renewable‑energy curtailment—the forced reduction of wind and solar output when supply exceeds demand—by storing excess generation for later use. More than 6,000 projects have been registered, together representing nearly 300 gigawatts of potential capacity, far surpassing Brazil’s current installed generation.
Cost allocation debate
The core controversy lies in whether the financial burden should fall solely on generators, as the law states, or be shared across the entire electricity system, as is done in other capacity reserve auctions. Battery industry groups such as Absae and Absolar argue that the generator‑only rule is anti‑isonomic and violates technological neutrality, because batteries provide the same system‑wide service as other reserve resources. They contend that the rule could trigger judicialization and jeopardize project implementation.
Opposing the change, consumer representatives and some generators maintain that it is unfair to shift costs to end‑users, noting that the auction addresses a problem—excess renewable generation—created by the generators themselves. They argue that generators should pay in proportion to the benefit they receive from reduced curtailment.
Regulators at Aneel have acknowledged the legal uncertainty surrounding the cost‑sharing mechanism. The agency’s technical division recently proposed extending the cost pool to all generators, including hydro and thermal plants, a suggestion that thermal generators have rejected, warning of possible litigation before the auction even takes place.
Implications for renewable integration
Despite the disagreement over who pays, there is broad consensus that battery storage can alleviate curtailment and improve the utilization of wind and solar farms. Supporters of the generator‑only stance, like Absae’s executive director Fabio Lima, claim that adding batteries reduces reliance on expensive peak‑load thermal plants, potentially lowering electricity tariffs overall. Meanwhile, consumer advocates such as Paulo Pedrosa of Abrace caution that socializing the costs would effectively subsidize generators at the public’s expense.
The Aneel board says it aims to finalize the regulatory framework before the auction, but the director‑general noted that the agency’s hands are tied by the existing law. Unless Congress amends the legislation—such as through a bill proposed by federal deputy Arnaldo Jardim to revoke the generator‑only provision—the auction may face further postponement or court intervention.
Sources consulted for this article indicate that without a clear resolution on cost allocation, the credibility of Brazil’s inaugural battery auction remains in jeopardy, casting doubt on its ability to deliver the intended boost to renewable energy integration.