Brazil Co-Located BESS: What ANEEL's 2026 Documentation Requirements Mean for Project Data

Regulatory update, 30 July 2026. ANEEL's page on electricity-storage systems co-located with generation plants was published on 20 July 2026 and updated on 29 July. It explains that ANEEL regulated procedures and requirements for adding electricity-storage systems to generation plants on 2 June 2026. For a developer, the immediate lesson is not that Brazil has issued one universal BESS metering specification. It is that a co-located project needs a technical file that can explain its site arrangement, operating assumptions, energy contribution and connection context. [1]

This guide separates what ANEEL explicitly identifies from practical engineering recommendations. It is not legal advice, a connection-agreement interpretation, a grid-code substitute or a claim that a particular meter, controller, EMS or BESS configuration is approved for Brazil.

1. What ANEEL has confirmed for co-located storage applications

ANEEL says that Normative Resolution No. 1,162/2026 inserted Article 16-A into Resolution No. 1,071/2023, which addresses authorisation requirements and procedures for wind, solar PV, thermal and other alternative generation sources. The applicable route depends on whether the generation plant already has an authorisation, but ANEEL's page directs co-location applicants to the relevant documentation. [1]

For the co-location documentation, ANEEL identifies the following items:

A general arrangement showing the perimeter of the electricity-storage system (SAE) and the restricted-interest network from the collector substation to the point of connection.
A technical study covering estimated annual injection, operating profile, overall efficiency, discharge power, storage capacity, and the technology and equipment description.
An environmental licence compatible with the project.
A signed CUST with ONS and, where applicable, a CUSD with the distribution utility, together with an access opinion or equivalent.
ANEEL's co-location executive-summary file and regulatory-requirements declaration. [1]

Officially confirmed: those are the project documents listed on ANEEL's co-location page. The page does not itself prescribe a universal meter model, accuracy class, communication protocol, recording interval, EMS platform or market-settlement arrangement. Those details must be confirmed from the applicable rule set, access documents, contracts and the actual architecture.

2. The technical study needs defined values, not just equipment names

The listed study inputs are connected. An annual-injection estimate depends on the assumed operating profile. An efficiency figure cannot be understood without knowing the energy boundary and calculation method. Discharge power and storage capacity describe different quantities, so neither should be used as a substitute for the other.

ANEEL-listed study input	Project question to settle before it is reported	Evidence type to retain
Estimated annual injection	At which electrical point is injection counted, and for which forecast period?	Defined calculation method, input data, assumptions and version record
Operating profile	Which charging, standby, discharge, curtailment or availability assumptions were used?	Time-based operating assumptions and change log
Overall efficiency	Between which stated input and output boundaries is the value calculated?	Boundary diagram, formula, direct measurements where used and calculation record
Discharge power	Is the reported value a design rating, a controlled setpoint or a measured result at a named point?	Equipment documentation, control assumptions and test/evidence record where applicable
Storage capacity	Is the value nominal, usable, contracted or derived under stated conditions?	Defined term, source document and stated conditions
Technology/equipment description	Which assets form the co-located facility and which remain outside the described boundary?	Single-line diagram, asset list and narrative description

Engineering recommendation: give every reported value a named boundary, source, time basis and version. That makes a technical file easier to review and later reconcile without turning an engineering estimate into an unsupported measured or settlement value.

Build the technical file from a defined site boundary and traceable inputs. -->

3. Do not treat all project data as the same kind of evidence

A co-located project can use several data sources, but they are not interchangeable.

Direct electrical measurement records energy or electrical quantities at a defined point and with a known time basis.
BMS, PCS, EMS or SCADA data can document operating state, commands, availability and controller-reported values. It does not automatically replace a defined electrical measurement point.
Calculated values can be suitable for a forecast, efficiency calculation or annual estimate when their inputs, formula and assumptions are retained.
Manual corrections or estimates should be labelled, dated and reconcilable to the source that required the correction.

For example, an energy value at the point of connection, an internal BESS charge/discharge value and an auxiliary-consumption value may answer different questions. Combining them in a single net number can remove the information needed to explain the operating profile or efficiency calculation. This is an engineering observation; it is not a statement that ANEEL has mandated a particular meter placement.

4. Start the measurement architecture with the project boundary

The general arrangement ANEEL requests is a useful starting point for the data design. Before selecting hardware or defining a dashboard, the project team should mark the electrical and reporting boundaries on a controlled single-line diagram.

Boundary or source	Decision to make	Why the distinction matters
Point of connection / collector-substation interface	Define how grid-facing import and export are identified under the applicable access and commercial arrangements.	It anchors the project to its stated connection context.
Generation side	Identify the generation output used in the annual-injection or operating-profile calculation.	It avoids silently mixing generation output with storage transfers.
Storage-system interface	Define the point used for any charge, discharge or throughput calculation.	It makes the efficiency boundary reviewable.
Auxiliary supplies	Decide whether HVAC, controls, transformers or other auxiliary use is separately visible for the intended calculation.	It prevents unexplained differences between energy flows.
Controller and data platform	State which data are operational logs and which values are direct measurements or calculated records.	It protects provenance and avoids false equivalence.

Keep electrical measurements, controller logs and calculations distinguishable. -->

5. A practical pre-submission evidence sequence

Freeze the project topology. Mark the SAE perimeter, restricted-interest network, collector substation and point of connection on the same controlled drawing.
Write the definition beside each study value. State what annual injection, operating profile, efficiency, discharge power and capacity mean for this application.
Map every value to a source. Identify whether it comes from direct measurement, a controller log, equipment documentation, a calculation or a manual adjustment.
Set time and version controls. Retain the reporting period, timestamp convention, source version, assumptions and any correction history.
Reconcile before submission. Check that diagrams, technical-study values, access documents and executive-summary statements use the same boundary and asset names.

This sequence does not add a new ANEEL obligation. It is a project-governance method for making the requested technical information coherent and reviewable.

6. Scope, conditions and YTL boundary

For a project-fit discussion with YTL, provide the controlled single-line diagram, intended measurement points, AC/DC or direct/CT/shunt arrangement, voltage and current range, required registers, data interval, interface/protocol expectations, data-retention need and the applicable project rule set. Exact product suitability, accuracy, certification scope, communication interface, register map, firmware behaviour and Brazilian project compatibility must be confirmed for the selected model and architecture.

YTL does not define ANEEL authorisation requirements, the SAE perimeter, CUST/CUSD obligations, grid-code compliance, formal connection acceptance, legal-metrology treatment, market settlement, BESS dispatch or BMS/PCS/EMS control logic. Its relevance is limited to the field measurement and data-output layer after the project owner has defined the required boundary and evidence use.

7. FAQ

Does ANEEL's co-location page create one universal BESS meter specification?

No. The cited page lists co-location documentation and technical-study inputs. It does not itself specify a universal meter model, accuracy class, protocol, interval or settlement arrangement.

What does ANEEL list for the technical study?

Estimated annual injection, operating profile, overall efficiency, discharge power, storage capacity, and a description of the technology and equipment. [1]

Can an EMS or BMS value be used as the only evidence for every project figure?

Not automatically. Controller data, direct electrical measurements and calculated values serve different purposes. The relevant project documents should define the boundary, source and calculation method for each reported value.

Does this guide decide a project's connection or regulatory compliance?

No. The relevant ANEEL rules, access opinion, CUST/CUSD where applicable, connection documents and project contracts remain the authoritative sources for that project.

What should be decided before asking an equipment supplier about a measurement solution?

The electrical topology, measurement boundary, voltage/current arrangement, expected data values, interval and retention needs, interface requirements and the applicable rule or contract.

Sources

Agência Nacional de Energia Elétrica (ANEEL), Sistemas de Armazenamento de Energia Elétrica (SAE) colocalizado a centrais geradoras (https://www.gov.br/aneel/pt-br/centrais-de-conteudos/manuais-modelos-e-instrucoes/armazeamento-de-energia/sae-colocalizado-a-centrais-geradoras), published 20 July 2026; updated 29 July 2026. This is the sole regulatory source for the factual claims in this article.