Although the Ministry of Mines and Energy (MME) is working towards holding the first reserve capacity auction with the participation of batteries in 2026, the board of directors of ANEEL The National Electric Energy Agency is still in the deliberation phase to establish the formal regulations for these assets.
Defining clear standards is seen as an important step, since storage is technically recognized as a resource capable of contributing to mitigating curtailment (restrictions on generation from renewable sources) and to balancing supply and demand in a system with increasing intermittency.
The need for a regulatory consensus became evident after the agency's board meeting held this Tuesday (10). The meeting, which, among other topics, dealt with operating rules and pricing, resulted in a further postponement of the decision, reflecting the different technical and economic assessments on how to integrate this technology into the national system.
Costing and pricing models
The central discussion within the scope of ANEEL The focus is on the tariff treatment applicable to the use of the network by storage systems. The process, which was under review by the director, is under review. Fernando Mosna Since August 2025, it has returned to the agenda with a proposal that aims to find economic viability for batteries.
Mosna presented a dissenting opinion arguing that the autonomous storage system should only bear the costs of its own generation at the moment it injects energy into the grid.
The point of greatest technical debate is the "dual charging" model. The previous proposal stipulated that batteries would pay for grid usage both during charging (like a consumer) and during injection (like a generator).
Mosna argued that this classification of consumption would be "artificial," since the storage device does not use the energy for its own benefit, but acts as an intermediary that shifts the supply over time, meeting a need of the system.
In their view, the application of consumption tariffs could be internalized in the prices offered at auctions, which could increase the final cost of contracting the capacity reserve for the consumer.
In addition to the tariff issue, Mosna proposed adjustments to the MUST (Amount of Use of Transmission and Distribution Systems). His suggestion foresees the possibility of an immediate 30% reduction in contracted capacity after the installation of storage equipment, replacing the previously proposed model of a gradual 5% annual reduction over six years.
According to the director, the system is already operational and capable of managing variations in amounts, provided there is adequate coordination and planning.
Cost allocation
Mosna's proposal, however, met with reservations from the director-general of ANEEL, Sandoval FeitosaDuring the deliberations, Feitosa expressed concern that the tariff exemption on loading could be interpreted as a specific sectoral advantage and stressed that the agency must ensure equity in the distribution of network charges.
According to the director-general, if storage systems do not contribute to the tariff for the use of the transmission network at the time of load, this residual cost would need to be absorbed by other energy consumers.
Feitosa argued that payment for the use of the transmission should be based on availability and that all users need to contribute to the cost of the infrastructure in appropriate proportions.
In its analysis, the agency faces a technical dilemma. That is, whether to allow a slightly higher transmission rate for everyone to ensure the efficiency of the competitive auction process, or to keep costs down, which could impact the bids in the auction.
The debate also underwent important procedural adjustments. In light of the sanction of... Law 15.269 / 2025, which conferred legal competence to ANEEL In order to regulate storage and determine that these systems be treated as distinct agents, the board decided, by a vote of 4 to 1, to annul the votes previously cast in the process.
This measure allows the current board, including directors Gentil Nogueira and Willamy Frota, to fully participate in the vote. Sandoval Feitosa was the only one to vote against the total annulment, suggesting that only the sections conflicting with the new law should be invalidated.
Despite the procedural alignment, the decision on the merits was postponed. Questions raised by directors Gentil Nogueira and Agnes da Costa regarding the regulations for closed-cycle reversible hydroelectric plants led Mosna to remove the process from the agenda.
The director indicated that he will submit these concerns to the Federal Prosecutor's Office at Aneel to ensure greater legal certainty for the final regulation.
Studies support the role of storage.
While the reserve auction focuses on large systems, studies reinforce that storage is necessary at various levels of the electricity grid.
A ABGD (Brazilian Association of Distributed Generation) already presented to ANEEL A technical survey detailing the strategic importance of these solutions for the distribution system.
The study, developed by MRST Consultoria in partnership with USP, used georeferenced data from the agency to analyze 27 feeders and approximately 6 million secondary networks.
For ABGD, batteries emerge as the ideal technical solution to mitigate undesirable effects and maximize the benefits of decentralized generation.
The organization argues that the evolution of the electricity sector is directly linked to stationary storage and the integration of batteries. electric vehicles.
This technological transformation process aims to solve operational challenges and enable generation close to the load to contribute more robustly to the overall stability of the system.
all the content of Canal Solar is protected by copyright law, and partial or total reproduction of this site in any medium is expressly prohibited. If you are interested in collaborating or reusing part of our material, please contact us by email: redacao@canalsolar.com.br.
