The energy transition is no longer merely an aspiration; it has become a concrete and urgent necessity. As Brazil continues to expand its clean energy matrix, particularly through solar and wind generation, the challenge of ensuring the stability, flexibility, and security of the electricity sector also grows.
In this context, Energy Storage Systems (ESS) emerge as indispensable tools for the efficient integration of intermittent renewable energy sources, whose inherent characteristics create challenges for the predictability and stability of the energy matrix. ESS therefore represent not only a promising technological solution but also a key component of the country’s energy future.
Despite their importance, energy storage remains largely outside the scope of Brazil’s regulatory framework. This situation carries a significant cost, reflected in missed opportunities to improve system efficiency, reduce losses, stabilize networks, and expand access to reliable and high-quality energy.
Storing electricity essentially means shifting the use of energy generated at one moment to another, more suitable time. This may be necessary for technical, economic, or security reasons. ESS can regulate frequency, provide rapid demand response, enable the operation of isolated systems, and reduce the need to dispatch fossil-fueled power plants.
In countries such as the United States, Australia, and Chile, although regulation is at different stages of development, energy storage already plays a structural role. In these jurisdictions, ESS participate in energy markets, are integrated into distributed generation schemes, and enhance both grid resilience and intelligence. Brazil, in turn, has been progressing more slowly in this area, though not without effort.
In this regard, the Brazilian Electricity Regulatory Agency (ANEEL) has undertaken important regulatory initiatives aimed at integrating ESS into the national electricity sector. Notable milestones include Public Consultation (Tomada de Subsídios) No. 11/2020 and the Regulatory Impact Assessment Report No. 1/2023, which identified key barriers to the development of this technology, including the conceptual uncertainty surrounding ESS (whether they should be classified as generation, load, or a new legal category), the absence of clear licensing rules, and inadequate remuneration models.
Given the regulatory complexity associated with integrating energy storage systems into the Brazilian electricity sector, ANEEL established a three-stage roadmap designed to progressively and coordinately develop a regulatory framework capable of providing legal certainty, economic efficiency, and technical feasibility.
The first stage of this process has already begun, with Public Consultation No. 39/2023 serving as its central milestone. This phase focused on establishing the initial conceptual and regulatory foundations. Key proposals included the creation of the figure of the Independent Storage Operator, greater flexibility in licensing requirements, the development of specific methodologies for grid-use contracting and tariff design, and the introduction of revenue stacking, allowing a single storage system to be compensated for multiple services provided to the electricity system.
The contributions received during this first phase were substantial and led to important refinements. One of the main adjustments involved revising the proposal concerning the Transmission and Distribution System Usage Contracted Capacity (MUST/D), allowing a reduction of up to 15% in contracted capacity under certain conditions to better reflect the bidirectional usage profile of ESS.
There was also progress in defining network-use tariffs that avoid the double charging of stored energy, acknowledging the distinct operational characteristics of this technology. In addition, the need for specific rules governing pumped-storage hydropower plants and hybrid models combining generation and storage was reaffirmed.
Following the conclusion of the first phase of the public consultation and the publication of Technical Note No. 266/2024, the process moved into its second stage. This phase focuses on more sophisticated operational mechanisms, including the development of remuneration rules for ancillary services provided by ESS, the incorporation of storage systems into energy planning models, and the definition of the role of aggregators, entities responsible for coordinating multiple distributed energy resources, including storage, through a unified operational platform.
This new stage, however, was marked by a period of uncertainty. In May 2025, the departure of reporting director Ricardo Tili and the reassignment of the proceeding to substitute director Daniel Cardoso Danna raised concerns regarding the pace and continuity of the process, particularly given the absence of public statements concerning future steps.
The regulatory process regained momentum in August 2025, when the proceeding initiated by Public Consultation No. 39/2023 was submitted for deliberation by ANEEL’s Board of Directors. During the meeting held on August 12, the Board appeared close to concluding the second phase, but the decision was postponed after Director Fernando Mosna requested additional time for review.
At the core of the debate lies the application of the principles of cost causation and economic-financial balance in defining transmission (TUST) and distribution (TUSD) network-use tariffs.
Director Daniel Danna’s opinion, supported by regulatory precedents and the assumptions set forth in Technical Note No. 13/2025, argued that an Independent Storage Operator, by functioning alternately as load and generation, makes distinct uses of the electrical infrastructure and should therefore contract and remunerate each form of use separately, similarly to self-producers and independent power producers. ANEEL’s Director-General, Sandoval Feitosa, further emphasized that no tariff duplication exists, since the charges correspond to different and complementary services.
Conversely, Director Fernando Mosna argued that the cumulative application of tariffs could impose excessive and disproportionate costs, potentially rendering Independent Storage Operators economically unviable. He advocated for the evaluation of more balanced regulatory solutions tailored to the technological characteristics of storage systems, even suggesting a transitional regulatory framework to avoid distortions and uphold the principle of technological neutrality.
Despite these differences, there was consensus regarding the classification of battery storage projects as Independent Power Producers (IPPs), with a 35-year authorization period and flexibility of up to 30% in network-use contracting for co-located projects and 5% for existing facilities.
Given the lack of consensus and the technical complexity involved, the final decision on tariff treatment was postponed, and the proceeding remains suspended pending further deliberation, with no defined date for resolution. This issue is central to the economic feasibility of storage projects, particularly autonomous systems, and will be decisive in shaping the next chapter of Brazil’s electricity matrix.
The third and final stage, yet to come, will focus on refining the rules necessary for the full integration of ESS across all segments of the electricity value chain, including transmission, distribution, and consumption. It is expected that this stage will culminate in the publication of a Normative Resolution consolidating the definitions developed throughout the process and formally incorporating energy storage into the Brazilian electricity sector.
Simultaneously, the Brazilian Congress is debating Bill No. 1224/2022, which seeks to establish a legal framework for ESS. Although well intentioned, the bill requires updating to reflect the most recent developments in sectoral regulation.
Also noteworthy is the technical event held on July 2 by the Chamber of Deputies’ Committee on Mines and Energy concerning the integration of energy storage systems into Brazil’s electrical systems. The initiative brought together experts, government representatives, and private-sector stakeholders and highlighted a broad consensus regarding the urgency of regulation and the importance of institutional alignment to unlock investments in the sector.
From a planning perspective, the Ten-Year Energy Expansion Plan 2034 (PDE 2034), prepared by the Energy Research Office (EPE), recognizes the strategic value of behind-the-meter ESS, particularly when combined with distributed generation, for demand management, peak-load reduction, and enhanced consumer autonomy.
To fully realize this potential, it will be essential to improve mechanisms such as time-of-use tariffs, two-part tariffs, and locational pricing signals that encourage the efficient use of energy. Without deliberate regulatory action, the market will remain constrained. Technically viable projects are likely to remain on paper, and the transformative potential of energy storage will continue to be underutilized.
Brazil has already demonstrated leadership in clean energy generation. However, leadership requires more than production—it requires modernization. Energy storage is no longer merely a trend; it is a strategic pillar for efficiency, stability, and flexibility in the electricity sector. Without a solid and functional regulatory framework for ESS, Brazil risks losing competitiveness, compromising energy security, and slowing the energy transition. The time has come to transform promises into results and technology into effective public policy.