Operational guide · Brazil
Brazil grid connection journey for generation and load
This journey starts with what a project must actually accomplish — not with a product catalog. It identifies who moves each step, the timeline that can honestly be stated, and the failures that send projects backwards. Existing tools are linked; missing ones remain visible.
Small/medium (DG)
Connection journey — distributed generation
The full process, including steps without a tool yet
- 1
Define the DG model and site
Local, remote or shared self-consumption, or EMUC; site, ownership and source.
- Owner
- Project owner, supported by the designer
- Typical timeline
- Before equipment purchase or the access filing.
- What goes wrong
- The chosen model is incompatible with ownership, site rights or credit allocation.
- 2
Assess resource and feasibility
Solar resource, yield, CAPEX, tariff and return at the actual site.
- Owner
- Project owner, installer and advisers
- Typical timeline
- During feasibility; repeat after a change in site, tariff or capacity.
- What goes wrong
- Generic resource data and omitted losses, Fio B or connection costs distort returns.
- 3
Check hosting capacity
Indicative feeder capacity and utility-published data.
- Owner
- The utility publishes data; the project owner screens it
- Typical timeline
- Fast screening, but confirmation only arrives in the connection budget.
- What goes wrong
- An indicative map is treated as reserved capacity or approval.
- 4
Compare TUSD/TUST and locational signals
Tariff, contracted capacity, charges and the point's long-term economics.
- Owner
- ANEEL approves tariffs; the utility or ONS applies them; the project owner models them
- Typical timeline
- At site selection and again before contractual commitments.
- What goes wrong
- The model uses an old tariff cycle or ignores contracted capacity and charges.
- 5
Prepare design and electrical studies
Protection, flow, quality and documents consistent with capacity and voltage.
- Owner
- Project owner and licensed engineer; the utility assesses
- Typical timeline
- Variable with capacity, voltage and additional studies.
- What goes wrong
- Forms, diagrams, equipment and capacity contain inconsistent data.
- 6
Run environmental and land permitting
Scope, studies and permits with the competent environmental authority.
- Owner
- Project owner before the competent federal, state or municipal authority
- Typical timeline
- Variable by location, impact, study and requests for additional information; start early.
- What goes wrong
- An assumed exemption or early permit is mistaken for full permission to build and operate.
Sources:Ibama — Licenciamento ambiental - 7
Obtain registration or generation authorization
The act depends on source, capacity and regulatory regime.
- Owner
- Project owner files; ANEEL regulates and issues the applicable act
- Typical timeline
- No single deadline; source, capacity and regime determine the procedure.
- What goes wrong
- The wrong procedure is used or authorization, access and permit data disagree.
- 8
Find the channel and documents
The responsible utility's portal, forms and technical standard.
- Owner
- Project owner files; the local utility receives and guides
- Typical timeline
- Before the formal request; verify current forms.
- What goes wrong
- The request goes to the wrong company, an informal channel or an obsolete form.
- 9
Connection request and budget
For Brazilian DG, the former access opinion now follows the connection-budget process.
- Owner
- Project owner submits a complete request; the utility assesses and issues
- Typical timeline
- REN 1,000: 15, 30 or 45 days depending on voltage, generation and works; defined circumstances can suspend the clock.
- What goes wrong
- Missing documents, reverse-flow analysis or consultation with another network disrupt the expected calendar.
- 10
Build, commission and clear operation
Connection works, protection, metering, telecoms, tests and operational release.
- Owner
- Project owner and grid owner execute their scopes; ONS participates where applicable
- Typical timeline
- Set mainly by required works and the contractual schedule; major reinforcements can take years.
- What goes wrong
- Interfaces lack an owner, or protection, metering, telemetry and tests are left until late.
- 11
Activate and audit compensation
Beneficiary units, metering, credits and Fio B charges.
- Owner
- The utility meters and bills; the account holder audits and maintains allocations
- Typical timeline
- After connection and during every billing cycle.
- What goes wrong
- Allocation is wrong, a beneficiary is missing or non-compensable charges were expected to disappear.
Large generator (transmission)
Connection journey — large generator
From site selection to operation on the Basic Grid/DIT
- 1
Assess resource, land and constraints
Energy resource, land, logistics, market and electrical proximity.
- Owner
- Project owner and specialist advisers
- Typical timeline
- Early development; revisit after changes to layout or connection point.
- What goes wrong
- A strong natural resource masks an unconnectable, unpermittable or insecure site.
- 2
Check SIN export margins
Indicative margin by busbar, queue and scenario — not a capacity reservation.
- Owner
- ONS publishes; the project owner compares points and scenarios
- Typical timeline
- Continuous screening using the latest publication; formal access must confirm it.
- What goes wrong
- Margins from different scenarios are added or the dashboard is treated as a positive opinion.
- 3
Compare TUSD/TUST and locational signals
Tariff, contracted capacity, charges and the point's long-term economics.
- Owner
- ANEEL approves tariffs; the utility or ONS applies them; the project owner models them
- Typical timeline
- At site selection and again before contractual commitments.
- What goes wrong
- The model uses an old tariff cycle or ignores contracted capacity and charges.
- 4
Define MUST or contracted demand
Transmission uses MUST; distribution uses demand under the applicable contract.
- Owner
- Project owner proposes; ONS or the utility assesses and contracts the applicable amount
- Typical timeline
- Defined before access and consolidated in the contract; phase it with the project ramp-up.
- What goes wrong
- Under-contracting creates exceedance exposure; over-contracting pays for idle capacity.
- 5
Perform electrical studies
Power flow, contingencies, short circuit, quality and applicable dynamics.
- Owner
- Project owner performs studies; ONS or the utility assesses them
- Typical timeline
- Iterative; repeat when the model, plant/load or point changes.
- What goes wrong
- An outdated model, mismatched assumptions or missing required cases creates a blocking issue.
- 6
Run environmental and land permitting
Scope, studies and permits with the competent environmental authority.
- Owner
- Project owner before the competent federal, state or municipal authority
- Typical timeline
- Variable by location, impact, study and requests for additional information; start early.
- What goes wrong
- An assumed exemption or early permit is mistaken for full permission to build and operate.
Sources:Ibama — Licenciamento ambiental - 7
Obtain registration or generation authorization
The act depends on source, capacity and regulatory regime.
- Owner
- Project owner files; ANEEL regulates and issues the applicable act
- Typical timeline
- No single deadline; source, capacity and regime determine the procedure.
- What goes wrong
- The wrong procedure is used or authorization, access and permit data disagree.
Sources:ANEEL — Outorgas de geração - 8
Submit the access request
Data, studies, schedule, point and capacity through the applicable channel.
- Owner
- Project owner files; the utility or ONS admits and assesses
- Typical timeline
- File early enough for the expected works; blocking issues stop progress.
- What goes wrong
- Documents, dates, registered data and studies do not match.
- 9
Receive the budget or access opinion
Feasibility, works, technical conditions, schedule and contracted capacity.
- Owner
- The utility issues the distribution budget; ONS issues the transmission opinion
- Typical timeline
- Distribution generally uses 15, 30 or 45 days. Transmission uses 30 days, 120 days or up to 1 year depending on works, without blocking issues.
- What goes wrong
- The regulatory document deadline is mistaken for the total energization schedule.
- 10
Execute use and connection contracts
Distribution contracts, or CUST with ONS and CCT with the transmission owner.
- Owner
- Project owner and utility, or project owner, ONS and transmission owner
- Typical timeline
- For transmission, execute CUST within 90 days after the opinion; distribution follows the budget and REN 1,000.
- What goes wrong
- Validity or reservation is lost, guarantees start late, or capacity and dates conflict with ramp-up.
- 11
Build, commission and clear operation
Connection works, protection, metering, telecoms, tests and operational release.
- Owner
- Project owner and grid owner execute their scopes; ONS participates where applicable
- Typical timeline
- Set mainly by required works and the contractual schedule; major reinforcements can take years.
- What goes wrong
- Interfaces lack an owner, or protection, metering, telemetry and tests are left until late.
Large load (demand)
Connection journey — load
From the load profile to commissioning
- 1
Define profile, site and phases
MW, hourly curve, power quality, redundancy, expansion and required date.
- Owner
- Project owner and designers
- Typical timeline
- Before land and connection commitments; revisit for each project phase.
- What goes wrong
- Only peak MW is disclosed, omitting ramps, harmonics, redundancy and expansion.
- 2
Screen distribution or transmission capacity
Select voltage and plausible points; generation hosting is not load capacity.
- Owner
- Utility or ONS assesses; the project owner compares alternatives
- Typical timeline
- Early screening; confirmation only in a formal budget or access opinion.
- What goes wrong
- Geographic proximity is mistaken for available electrical capacity.
- 3
Compare TUSD/TUST and locational signals
Tariff, contracted capacity, charges and the point's long-term economics.
- Owner
- ANEEL approves tariffs; the utility or ONS applies them; the project owner models them
- Typical timeline
- At site selection and again before contractual commitments.
- What goes wrong
- The model uses an old tariff cycle or ignores contracted capacity and charges.
- 4
Define MUST or contracted demand
Transmission uses MUST; distribution uses demand under the applicable contract.
- Owner
- Project owner proposes; ONS or the utility assesses and contracts the applicable amount
- Typical timeline
- Defined before access and consolidated in the contract; phase it with the project ramp-up.
- What goes wrong
- Under-contracting creates exceedance exposure; over-contracting pays for idle capacity.
- 5
Perform electrical studies
Power flow, contingencies, short circuit, quality and applicable dynamics.
- Owner
- Project owner performs studies; ONS or the utility assesses them
- Typical timeline
- Iterative; repeat when the model, plant/load or point changes.
- What goes wrong
- An outdated model, mismatched assumptions or missing required cases creates a blocking issue.
- 6
Run environmental and land permitting
Scope, studies and permits with the competent environmental authority.
- Owner
- Project owner before the competent federal, state or municipal authority
- Typical timeline
- Variable by location, impact, study and requests for additional information; start early.
- What goes wrong
- An assumed exemption or early permit is mistaken for full permission to build and operate.
Sources:Ibama — Licenciamento ambiental - 7
Submit the access request
Data, studies, schedule, point and capacity through the applicable channel.
- Owner
- Project owner files; the utility or ONS admits and assesses
- Typical timeline
- File early enough for the expected works; blocking issues stop progress.
- What goes wrong
- Documents, dates, registered data and studies do not match.
- 8
Receive the budget or access opinion
Feasibility, works, technical conditions, schedule and contracted capacity.
- Owner
- The utility issues the distribution budget; ONS issues the transmission opinion
- Typical timeline
- Distribution generally uses 15, 30 or 45 days. Transmission uses 30 days, 120 days or up to 1 year depending on works, without blocking issues.
- What goes wrong
- The regulatory document deadline is mistaken for the total energization schedule.
- 9
Execute use and connection contracts
Distribution contracts, or CUST with ONS and CCT with the transmission owner.
- Owner
- Project owner and utility, or project owner, ONS and transmission owner
- Typical timeline
- For transmission, execute CUST within 90 days after the opinion; distribution follows the budget and REN 1,000.
- What goes wrong
- Validity or reservation is lost, guarantees start late, or capacity and dates conflict with ramp-up.
- 10
Build, commission and clear operation
Connection works, protection, metering, telecoms, tests and operational release.
- Owner
- Project owner and grid owner execute their scopes; ONS participates where applicable
- Typical timeline
- Set mainly by required works and the contractual schedule; major reinforcements can take years.
- What goes wrong
- Interfaces lack an owner, or protection, metering, telemetry and tests are left until late.
Frequently asked questions
How long does a Brazilian grid access opinion take?
For transmission, ONS states 30 days when no works are required, 120 days when reinforcements or improvements are required, and up to one year when expansions are required, provided there are no blocking issues. In distribution, REN 1,000 generally sets 15, 30 or 45 days for the connection budget depending on voltage, installation type and works, with specified grounds for suspension. These are not total build-and-energize timelines.
What is generation export margin?
It indicates how much additional generation a grid point may accommodate in the assessed scenarios without breaching electrical criteria. The ONS dashboard helps compare SIN busbars, but it neither reserves capacity nor replaces the formal access opinion.
Does a generator need MUST?
It depends on the connection. A generator using transmission contracts the Montante de Uso do Sistema de Transmissão (MUST) through its CUST, as established in the access process. Brazilian micro or mini distributed generation under SCEE does not sign a CUST or contract MUST; it follows the utility process.
Does hosting capacity guarantee a distributed-generation connection?
No. Hosting capacity is an indicative feeder screen. Actual conditions, works, costs and timing are set in the utility's connection budget after a complete request is assessed.
What is the difference between TUST and TUSD?
TUST charges for use of transmission; TUSD charges for use of distribution. The applicable tariff depends on the facilities accessed and the user's regulatory status. Both must be assessed together with contracted capacity and location.
Are ANEEL authorization and environmental licensing the same process?
No. ANEEL handles the generation regulatory act, which varies by source, capacity and regime. Environmental licensing is handled by the competent environmental authority and addresses location, impacts and conditions. Both must remain consistent with the grid-access design.