Brazil’s National Electric Energy Agency, Agência Nacional de Energia Elétrica (ANEEL), has taken a decisive step towards modernising the country’s power sector by launching a new phase of regulatory discussion focused on energy storage.
Through Technical Note No. 03/2026, the regulator has opened a formal debate to align existing rules with Law No. 15,269, enacted in November 2025, which formally recognised energy storage as an independent activity within Brazil’s electricity market.
The initiative complements the second phase of Public Consultation No. 39/2023 and introduces structural guidelines defining how batteries and other storage technologies will operate, charge and be remunerated within the National Interconnected System (Sistema Interligado Nacional – SIN).
One of the most anticipated issues for investors in renewable energy and energy storage was the tariff framework. ANEEL confirmed that the so-called “dual tariff” will remain in place for battery energy storage systems (BESS).
In practice, this means storage assets will not be exempt from paying for network use. The regulator argues that Law 15,269 does not relieve storage systems from remunerating grid availability, since they use infrastructure in both directions.
Storage operators must therefore pay Transmission or Distribution Use of System Tariffs (TUST/TUSD):
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When withdrawing electricity from the grid to charge (as consumers);
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When injecting electricity back into the grid (as generators).
The decision provides regulatory certainty but may affect project economics, particularly for standalone BESS competing in ancillary services, energy arbitrage and capacity markets.
Creation of a new legal figure: the Autonomous Storage Agent
The regulation also introduces a new legal and operational category: the Autonomous Storage Agent (Agente Armazenador Autônomo).
Previously, storage projects were framed under generation rules. The new law removes this parallel treatment and establishes a distinct licensing regime.
Key distinctions:
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Specific licence: An exclusive authorisation (outorga) will be issued for storage projects, with a dedicated registration code (SAE), separate from generation assets.
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No capacity threshold exemption: Unlike small-scale distributed generation, standalone storage services will require ANEEL authorisation regardless of installed capacity, as there is no explicit legal exemption similar to that granted to small renewable energy projects.
The technical note further clarifies that if centralised planning determines a storage system is required for Basic Grid infrastructure, it will be treated as a transmission asset and must be competitively tendered through public auctions.
However, Pumped Storage Hydropower Plants (Usinas Hidrelétricas Reversíveis – UHR) are explicitly excluded from this mandatory transmission auction framework and will maintain a differentiated regulatory regime.
Hybrid projects combining renewable energy generation — such as solar PV or wind power plants — with battery systems at the same grid connection point will retain efficiency incentives.
These co-located projects may contract a Montante de Uso do Sistema (MUST, contracted grid capacity) up to 20% below total installed capacity. This reflects the technical capability of batteries to smooth injection peaks, optimise grid integration and reduce stress on transmission infrastructure.
The measure supports investment in renewables, grid flexibility and energy storage as complementary technologies, particularly in regions with high penetration of intermittent renewable energy.
In a decision designed to protect end consumers, ANEEL implemented the provisions of Law 15,269 by determining that costs arising from contracting batteries as capacity reserve — i.e. contracted firm power to ensure system reliability — will be borne exclusively by generation agents.
This means such costs will not be directly passed through to residential or industrial electricity tariffs.
Moreover, new generation projects requesting grid access will be required to fund a mandatory capacity reserve if they fail to meet minimum technical requirements for flexibility and storage capability.
This provision reinforces system security while incentivising more flexible and storage-integrated renewable energy projects.
Next steps in the regulatory agenda
ANEEL has split the implementation into two regulatory instruments:
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A specific rule governing the storage licensing process.
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A cross-cutting regulation amending existing rules, including REN 1,000.
More complex issues — such as the integration of storage assets into energy traders’ (Comercializadores de Energia) portfolios — have been deferred to a second regulatory cycle.
The new consultation marks a significant milestone for Brazil’s energy transition, offering greater clarity for investors in battery energy storage systems, distributed generation, grid integration and broader renewable energy deployment across Latin America’s largest power market.
