Marvin Menezes

With the collaboration of Bianca Wolf. The discipline of costing the contracting of battery energy storage systems via capacity reserve auctions has been the subject of discussion since the enactment of Law No. 15.269/2025, which altered the legal framework applicable to capacity reserves and established a specific allocation rule for this type of contracting. With the approach of the Capacity Reserve Auctions for storage systems, scheduled for December 2026, the topic has gained greater relevance. In this context, the Superintendence of Regulation of Generation Services and the Electricity Market of ANEEL (National Electric Energy Agency) presented, on August 24, 2026, Technical Note No. 101/2026 and Regulatory Impact Analysis Report No. 5/2026, within the scope of Process No. 48500.021812/2026-21. The documents present a proposal to regulate the Capacity Reserve Charge associated with the contracting of battery storage systems (ERCAP-SAE), in addition to identifying legal controversies still submitted to the Federal Attorney's Office at the ANEELLegal Framework and Scope of the Proposal Article 3-A of Law No. 10.848/2004 establishes that the costs of contracting reserve capacity will be shared among the end users of the SIN (National Interconnected System), including self-producers in the portion of energy resulting from interconnection to the system, and among generators in the cases provided for in the legislation. For the contracting of battery storage systems, paragraph 6 of the article introduced a specific rule, namely, that the respective costs should be shared only among energy generators, according to the regulations of ANEELThe legislation, however, did not detail the calculation basis, the allocation methodology, the frequency of charges, or the classification of specific agents. The proposal under discussion seeks to regulate these aspects, without directly addressing the general rules of ERCAP or the requirements applicable to new accessors as provided for in Article 8-A of Law No. 9.074/1995. Proposed allocation methodology With this in mind, the technical area of ANEEL The analysis examined three alternatives: (i) universal apportionment without differentiation between generators; (ii) apportionment restricted to projects classified as inflexible; and (iii) universal apportionment with graduation according to the flexibility of each plant. The recommended alternative keeps all generators included in the cost base, but applies different coefficients according to four levels, as follows: P1 — inflexible: coefficient of 1,00. P2 — low flexibility: coefficient of 0,75. P3 — high flexibility: coefficient of 0,50. P4 — very high flexibility: coefficient of 0,25. The model does not establish full exemption for the most flexible projects. The differentiation affects the value of the contribution, preserving its participation in the apportionment base. The methodology preferably considers the energy effectively generated in the assessment period. Thus, the absence of generation in a given cycle may preclude collection in that period, without excluding the project from the universe of agents subject to the charge. The flexibility indices would be defined according to the characteristics of each source: production modulation for hydroelectric plants; Operational parameters, such as ramps and start-up times, for thermal power plants; and generation control or shifting capacity, including through associated storage, for wind and solar power plants. Main legal and regulatory controversies The definition of the universe of payers is one of the central points of discussion. The technical proposal considers the inclusion of generation agents linked to CCEE (Chamber of Electric Energy Commercialization), including holders of concessions or registration, according to the applicable regime. In this context, the classification of self-producers remains under analysis, especially when they also act as generation agents. It is also debated whether the charge should apply to the total generation of the project or only to the portion exported to the grid. In self-production structures by equivalence, there is also a need to distinguish the equivalent consumer from the company holding the concession or registration of the generating plant, a circumstance that may influence the identification of the party responsible for payment. Another controversy involves the relationship between ERCAP-SAE and Article 8-A of Law No. 9.074/1995. This provision establishes that projects requesting access to transmission or distribution systems after its publication must pay for the capacity reserve, in proportion to the energy generated, until they meet the control, capacity, flexibility, and storage requirements defined in the regulations. The coexistence of these rules raises questions about the autonomy of the regimes, the possibility of simultaneous application, and the mechanisms necessary to avoid double billing. The extent of the authority's jurisdiction also remains under discussion. ANEEL to differentiate the amounts due according to the flexibility, source, or operational profile of the projects. Beyond the legal aspect, the implementation of the methodology will depend on the definition of applicable parameters, the availability of information, and the coordinated action of... ANEELThe proposal also considers that micro and mini-distributed generation, subject to the regime of Law No. 14.300/2022, and autonomous storage systems are not part of the ERCAP-SAE payer base. Composition of the charge and contractual implications: The cost of the LRCAP-SAE is integrated into the existing structure of the ERCAP and the Power Account for Capacity Reserve (CONCAP). According to MME Normative Ordinance No. 136/2026, the energy used for charging and the energy injected by storage systems will be settled in the Short-Term Market at the PLD, with the respective results allocated to CONCAP, observing the applicable limits. The technical analysis starts from this discipline and emphasizes that the cost requirement will not only be associated with the Fixed Revenue of the contracts, but will also be influenced by the results of the operation, which vary according to the PLD and the dispatch determined by the ONS. In this context, the Regulatory Impact Analysis (AIR) also examines the potential repercussions of the new charge on already signed trading contracts, especially those containing clauses for adjustments due to the creation of sector charges. The Technical Note also addresses the possible effects of the charge on CCEARs (Energy Trading Contracts in the Regulated Environment) and CERs (Reserve Energy Contracts) that contain adjustment clauses related to the creation of new sector charges. In these cases, the possibility of regulatory allocation of the amounts to buyers, proportionally to the contracted amounts, through operationalization by CCEE, is considered. The application of this solution will depend on the identification of the contracts covered and their respective contractual provisions. Next steps The SGM recommended opening a specific public consultation for a period of 30 days, in addition to holding a workshop to discuss the eligibility criteria and the allocation methodology. The proposal is still subject to review by the Federal Attorney's Office, assessment by the Board of Directors, and revision of Normative Resolution No. 1.009/2022, followed by the necessary adjustments to the Rules and Procedures for Commercialization. The discussion on ERCAP-SAE should not be confused with Public Consultations No. 22/2026 and No. 23/2026, which deal with the bidding documents for the auctions scheduled for December 2 and 4, 2026. Until the regulatory process is concluded, the definitive delimitation of the responsible agents, the treatment of self-production, the interaction with the rules applicable to new accessors, the criteria for differentiation between projects, and the contractual implications of the methodology to be adopted remain pending.

Marvin Menezes

Published articles

ERCAP-SAE: Current status of regulation and controversies regarding the allocation of storage auction costs.

From regulatory debate to power contracting: energy storage and the first battery auctions in Brazil.