Data · ANEEL, ONS, CCEE and EPE · as of September 29, 2026
Generators in Brazil’s grid: curtailment, thermal dispatch and where the curtailed energy can go
A consolidated panel of ANEEL, ONS, CCEE and EPE (PDE 2035) data. Brazil’s interconnected system (SIN) now runs in daytime oversupply: 37.2 TWh of wind and solar were curtailed in 2025, 20.7% of potential output, and in 2026 70% of curtailment is due to energy reasons, the share that is not compensated. Meanwhile, 43% of thermal dispatch in 2025 ran out of merit order.
Summary
Six numbers that describe the generation fleet in 2026
Interpretation
What these numbers mean for generators
The system has surplus energy in sunny and windy hours, and curtailment has shifted from a grid problem to a market problem. The reading below is Amatiri’s, with the assumptions stated at the end of the page.
Curtailment is now energy-driven, and that share is not compensated
Utility-scale wind and solar already equal 50% of SIN load between 9 a.m. and 4 p.m. and exceed Northeast load in 98% of the hours of September and October. In 2024, curtailment was mostly for grid reliability. In 2026, 70% is for energy reasons: there is too much energy, not too little transmission.
This is exactly the share that ANEEL REN 1,030/2022 and Law 15,269/2025 leave uncompensated, and the ruling of the 13th Federal Court of the Federal District on Sep 14, 2026 rejected full compensation.
Energy-driven share of curtailment
% of total wind and solar curtailment
Calculated from ONS annual totals.
The curtailed volume tripled in one year
From 12.8 TWh in 2024 to 37.2 TWh in 2025, and 29.1 TWh in January–September 2026 alone. At the average Northeast spot price, the energy curtailed in 2025 is worth R$6.6 billion. The hardest-hit clusters are in Rio Grande do Norte, Bahia, Piauí and northern Minas Gerais, with cuts of 20% to 50% of reference output.
Wind and solar curtailed
TWh
Out-of-merit thermal runs alongside renewable curtailment
In 2025, 28.3 TWh of thermal power ran out of merit order and 21.0 TWh of turbinable hydro was spilled, while wind and solar were being curtailed. At light load, 49% of thermal output is inflexibility or unit commitment. The thermal cost in July 2026 was R$1.585 billion, 90% of it inflexibility.
Out-of-merit thermal
% of actual thermal generation
Curtailed energy has an opportunity cost close to zero
A flexible load of 20% to 30% of plant capacity, installed behind the metering point, captures 80% to 90% of curtailed energy at a 50% to 60% utilization factor. For batteries, merchant arbitrage does not pay for the asset: the capacity auction’s fixed revenue is the economic engine.
Our reading: by December 2026, storage of 30 MW/120 MWh or more at bonus buses, with a supplier accredited in the BNDES CFI catalog, and 10–30 MW flexible-load pilots at plants curtailed above 20%. In 2027 and 2028, hybridization and standardized load hosting in RN, BA, northern MG, PI and CE. From 2028 on, firm-load hubs such as data centers and hydrogen, integrating generation, storage and grid access.
Curtailed energy captured
by flexible load as a share of plant capacity
Study heuristic; utilization falls from 68% to 28% over the same range.
Sources: ANEEL (SIGA, RALIE, distributed generation), ONS (constrained-off, thermal dispatch, spillage), CCEE (InfoMercado, spot price) and EPE (PDE 2035). Interpretation and assumptions by Amatiri Energia.
Generation fleet
220.5 GW in operation, and a shrinking pipeline
Large hydro is still almost half of capacity, but wind and utility-scale solar already add up to 26.5%. Outside SIGA, distributed generation reaches 54.0 GW across 4.66 million connections.
ANEEL SIGA, Sep 1, 2026 · capacity in operation, excluding distributed generation
| Source | Plants | MW in operation | % | Firm energy · avg MW |
|---|---|---|---|---|
| Hydro (large) | 216 | 103,242 | 46.8% | 55,655 |
| Thermal | 3,043 | 49,710 | 22.5% | 15,944 |
| Wind | 1,138 | 34,937 | 15.8% | 16,213 |
| Utility-scale solar | 17,277 | 23,603 | 10.7% | 6,286 |
| Small hydro (PCH) | 435 | 6,084 | 2.8% | 3,350 |
| Nuclear | 2 | 1,990 | 0.9% | 1,714 |
| Mini hydro (CGH) | 711 | 928 | 0.4% | 214 |
| Total | 22,822 | 220,493 | 100% | 99,375 |
Capacity in operation by source
GW
Distributed generation connected per year
GW · 2026 through September
Expected additions 2026–2030 (RALIE)
GW by source · approximate values, read from the study chart
Permits: new authorizations vs revocations
GW in ANEEL acts · 2026 through September · approximate values, read from the study chart
SIN generation by source
TWh, ONS · approximate values, read from the study chart
The pipeline shows the turn. There are 9.2 GW under construction and 90.0 GW permitted with no works started, 72.8 GW of them solar. But RALIE counts only about 13.2 GW as firm between 2026 and 2030, and in 2025 and 2026 permit revocations overtook new authorizations. A large part of what was authorized in 2022 and 2023 will not be built.
Contracting and prices
No new-energy auction has contracted wind or solar since 2024
Monthly average spot price (PLD) by submarket
R$/MWh, CCEE · 2025 average checked against the study: SE/CO R$224, NE R$177 · approximate values, read from the study chart
Auctions, 2024–2026
| Auction | Date | Volume | Price |
|---|---|---|---|
| Existing-energy A-1/A-2 2024 | Dec 6, 2024 | 1,621.5 + 508.8 avg MW | R$162 / 161 per MWh |
| 39th new-energy A-5/2025 (hydro) | Aug 22, 2025 | 384.5 avg MW | R$392.84/MWh |
| Existing-energy A-1/A-2/A-3 2025 | Nov 14, 2025 | 1,778.6 avg MW | R$205–213/MWh |
| 4th capacity reserve auction (LRCAP) 2026 | Mar 18, 2026 | 18,977 MW | R$2.33 million/MW-year |
| 5th LRCAP 2026 (oil) | Mar 20, 2026 | 501.3 MW | R$831 thousand/MW-year |
| Auctions 05 and 06/2026 · storage | Dec 2 and 4, 2026 | 2 GW reference · 296.8 GW registered | to be set |
Regulated quantity contracts at about 15.0 avg GW; availability contracts at about 13.4 avg GW; physical-guarantee quotas down from 7.2 to 4.4 avg GW between 2024 and Jul 2026.
Curtailment (constrained-off)
Wind and solar curtailment, month by month
Curtailment peaks during the windy season, August to October, and the energy-driven share, in dark blue, dominates from mid-2025.
Energy curtailed by month and reason
TWh and % of potential generation, ONS, Jun 2024–Sep 2026 · months reconciled to ONS annual totals · approximate values, read from the study chart
| Year | Source | Actual generation · TWh | Curtailed · TWh | External | Reliability | Energy | % curtailed | Clusters |
|---|---|---|---|---|---|---|---|---|
| 2024 | Wind | 102.67 | 9.55 | 0.87 | 5.84 | 2.84 | 8.5% | 173 |
| 2024 | Solar | 21.05 | 3.25 | 0.30 | 1.39 | 1.55 | 13.4% | 65 |
| 2025 | Wind | 111.07 | 26.22 | 3.28 | 9.60 | 13.33 | 19.1% | 162 |
| 2025 | Solar | 31.72 | 11.00 | 1.37 | 2.88 | 6.75 | 25.8% | 73 |
| 2026 (Jan–Sep) | Wind | 76.42 | 19.47 | 2.34 | 5.13 | 12.00 | 20.3% | 156 |
| 2026 (Jan–Sep) | Solar | 27.34 | 9.62 | 0.68 | 0.63 | 8.31 | 26.0% | 86 |
Curtailment by source and year
TWh curtailed
Reason for curtailment, % of total
calculated from ONS annual totals
Curtailment by state
TWh · RN, BA, MG, PI and CE from the study data; other states approximate
Wind and solar over SIN load, by hour
% of load, average by hour of day · approximate values, read from the study chart
Wind and solar over Northeast load, by month
% of Northeast load · approximate values, read from the study chart
The 15 most curtailed clusters in 2026
GWh curtailed, Jan–Sep 2026
| # | Cluster | Source | UF | Agent | Curtailed · GWh | Energy share | % of reference |
|---|---|---|---|---|---|---|---|
| 1 | Conj. Janaúba | Solar | MG | ELERA RENOVAVEIS | 648 | 82% | 26.6% |
| 2 | Conj. Caju | Wind | RN | AUREN OPERAÇÕES | 564 | 34% | 32.4% |
| 3 | Conj. Santo Agostinho | Wind | RN | ENGIE | 505 | 41% | 41.6% |
| 4 | Conj. Arinos 2 500 kV | Solar | MG | VOLTALIA | 500 | 96% | 22.5% |
| 5 | Conj. Rio do Vento Expansão | Wind | RN | CVER | 478 | 43% | 25.5% |
| 6 | Conj. Rio do Vento | Wind | RN | CVER | 461 | 52% | 26.4% |
| 7 | Conj. Monte Verde | Wind | RN | EDP BRASIL | 446 | 41% | 31.7% |
| 8 | Conj. Serra do Assuruá | Wind | BA | ENGIE | 445 | 66% | 17.4% |
| 9 | Conj. Gilbués II 500 kV | Solar | PI | ENEL | 400 | 82% | 28.6% |
| 10 | Conj. Curral Novo do Piauí II 230 kV | Wind | PI | AUREN OPERAÇÕES | 366 | 78% | 11.3% |
| 11 | Conj. Vista Alegre – Janaúba | Solar | MG | IQONY | 365 | 83% | 24.9% |
| 12 | Conj. Assu Sol | Solar | RN | ENGIE | 343 | 78% | 28.3% |
| 13 | Conj. Jerusalém | Wind | RN | STATKRAFT | 334 | 44% | 41.5% |
| 14 | Conj. Lagoa dos Ventos | Wind | PI | ENEL | 333 | 83% | 13.0% |
| 15 | Conj. Santa Vitória do Palmar | Wind | RS | SIMM | 331 | 8% | 51.4% |
Thermal dispatch and oversupply
Out-of-merit thermal and spilled water in the same system that curtails renewables
Thermal generation by fuel
TWh · ONS-dispatched plants · approximate values, read from the study chart
Thermal by merit order
TWh, ONS
| Year | Actual · TWh | Merit order | Inflexibility | Unit commitment | Exports | Out of merit | % |
|---|---|---|---|---|---|---|---|
| 2023 | 43.8 | 0.8 | 36.9 | 2.17 | 3.26 | 43.0 | 98% |
| 2024 | 57.8 | 20.3 | 37.2 | 5.39 | 2.67 | 37.5 | 65% |
| 2025 | 65.5 | 37.2 | 42.3 | 2.77 | 3.49 | 28.3 | 43% |
| 2026 (Jan–Sep) | 46.6 | 25.0 | 29.3 | 2.52 | 2.71 | 21.5 | 46% |
Turbinable spillage by subsystem
TWh, ONS · approximate values, read from the study chart
The cost of keeping thermal online
At light load, 49% of 2025 thermal output was inflexibility or unit commitment. The thermal cost in July 2026 was R$1.585 billion, 90% of it inflexibility.
Median variable unit cost in September 2026, in R$/MWh: gas 1,200, coal 361, fuel oil 1,309, diesel 2,903 and nuclear 25.6.
Opportunities
Loads behind the metering point: what fits each plant
| Application | CAPEX | Flexibility | Minimum viable utilization |
|---|---|---|---|
| Bitcoin mining (hosting) | R$10.8 million/MW | Full, within seconds | 30–60% |
| Co-located 4-hour BESS | R$5.5 million/MW | Full, within milliseconds · 366 cycles/year in LRCAP | n/a · spread plus fixed revenue |
| H2 electrolysis, full system | R$12.4 million/MW | High · PEM 10% to 100% | 50–60% or more, for LCOH |
| AI and cloud data center | R$61.0 million/MW | Almost none · Tier III/IV | above 90% |
| Energy-intensive · aluminum, 14.8 MWh/t | US$4–8 thousand per t-year | Low · a few % | above 90% · up to US$40/MWh firm |
Capture of curtailed energy and load utilization
% · by flexible load as a share of plant capacity (horizontal axis) · heuristic · approximate values, read from the study chart
Possible flexible load by state and source
MW · screening heuristic: annualized curtailment × 0.85 ÷ (8,760 × 0.55)
| UF | Source | Capacity · MW | Curtailed 2025 · TWh | Curtailed Jan–Sep 26 · TWh | % curtailed 2026 | Avg MW curtailed | Flexible load · MW | % of capacity |
|---|---|---|---|---|---|---|---|---|
| RN | Wind | 10,726 | 10.82 | 8.33 | 31.0% | 1,271 | 1,964 | 18% |
| BA | Wind | 11,832 | 8.98 | 6.21 | 17.6% | 947 | 1,464 | 12% |
| MG | Solar | 8,767 | 5.00 | 3.67 | 25.2% | 560 | 866 | 10% |
| PI | Wind | 4,396 | 2.39 | 1.77 | 12.6% | 270 | 417 | 9% |
| BA | Solar | 3,045 | 1.89 | 1.73 | 32.8% | 264 | 407 | 13% |
| CE | Wind | 2,690 | 2.22 | 1.17 | 25.5% | 178 | 275 | 10% |
| PI | Solar | 2,404 | 1.28 | 1.10 | 26.8% | 168 | 259 | 11% |
| RN | Solar | 2,113 | 0.88 | 0.95 | 24.8% | 145 | 224 | 11% |
| CE | Solar | 2,298 | 0.73 | 0.80 | 21.6% | 122 | 189 | 8% |
| PB | Wind | 1,234 | 0.82 | 0.74 | 11.8% | 112 | 174 | 14% |
| RS | Wind | 2,051 | 0.27 | 0.70 | 17.0% | 107 | 165 | 8% |
| SP | Solar | 1,223 | 0.32 | 0.53 | 29.8% | 81 | 125 | 10% |
| Total | 6,529 |
The 12 state-source pairs in the table add up to about 6.5 GW of flexible load.
Illustrative case: 300 MW wind farm in RN
| Item | Value |
|---|---|
| Potential generation (45% CF) · curtailed (25%) | 1,183 · 296 GWh/year |
| Flexible load of 25% · capture · utilization | 75 MW · 251 GWh · 38% |
| Value of captured energy at 2025 NE PLD | R$44.4 million/year |
| Mining load CAPEX, borne by the partner | R$810 million |
| BESS at 30% / 4 h · CAPEX · LRCAP fixed revenue · payback | R$495 million · R$112.5 million/year · 4.4 years |
| Merchant arbitrage (300 cycles, R$120/MWh spread) | R$11.4 million/year |
Key regulation
| Rule | Effect |
|---|---|
| ANEEL REN 1,030/2022 + 1,073/2023 | Compensation only for external unavailability above the allowance (78 h wind, 30 h 30 min solar) |
| Law 15,269/2025 + MME Ordinance 140/2026 | Retroactive compensation (Sep 2023 to Nov 2025) for external unavailability and reliability, excluding oversupply; self-generation by equivalence (from 30 MW / 3 MW); REIDI tax regime for storage; battery capacity charge paid by generators |
| ANEEL REN 1,161 and 1,162/2026 | Standalone, co-located and pumped storage; 35-year authorization; injection-only transmission contract for ONS-dispatched storage; up to 30% transmission-contract reduction for co-located storage |
| REN 1,122/2025 + Decree 12,772/2025 (PNAST) | Guarantees and access seasons for large loads |
| Law 15,504/2026 (Redata) | Data-center tax exemptions conditional on 100% renewable or low-emission power, via contracts or self-generation |
| 13th Federal Court/DF (Sep 14, 2026); ANEEL (Sep 22–25, 2026) | Full compensation claim dismissed; injunctions denied |
Expansion · PDE 2035
Flexible thermal and batteries lead the indicative expansion
Cumulative indicative expansion by source
GW, reference case, PDE 2035 · “other” is the gap between the plan total and the five detailed sources
Capacity mix, 2025 and 2035
GW · 2035 as stated in the study; 2025 approximate
SIN load by scenario
avg GW · approximate values, read from the study chart
Utility-scale solar only returns to the plan in 2032, because of energy curtailment, and distributed generation grows from 40 to 78 GW. The PDE does not project curtailment quantitatively.
December 2026 storage auctions
296.8 GW registered for a 2 GW reference demand
| Item | Definition |
|---|---|
| Product | Power for 4 h per cycle, up to 2 cycles a day, 366 a year, recharge within 6 h; grid-forming; new batteries |
| Remuneration | Fixed revenue indexed to IPCA inflation; energy at PLD via CONCAP; no revenue stacking; dispatch risk borne by the developer |
| Location | β = 0.9 at about 150 buses in AL, BA, CE, MG, PB, PE, PI and RN (Annex II, MME Ordinance 136/2026) |
| Local content | BNDES CFI stage 1, IEP of 15% or more: WEG, Moura, You.On, TBEA, Gotion, Trina and BYD (packs); Moura and Automa (EMS) |
| Open items | Quantity (2 GW reference), opening price, ONS technical note on remaining capacity (Sep 30), tender notice (~Oct 29), qualification (Nov 17) |
| Points from ANEEL consultations | Standalone storage only; penalties of 1.10 and 1.15; capacity charge paid by generators (Bill 3,716/2026 seeks to reverse it) |
Outlook
With CAPEX of R$5,500/kW, per the PDE, and fixed revenue of R$1.25 million/MW-year, simple payback is about 4.4 years. There is room for a significant discount if demand stays at 2 GW against 296.8 GW registered; EPE expects a sharp drop at qualification. The opposite risk is a thin national auction, given the limited number of accredited manufacturers.
Upward pressures: double transmission charges for free operation, penalties, grid-forming requirements, the exchange rate and uncertainty over who pays the capacity charge. Downward pressures: LFP batteries at US$130–160/kWh turnkey, the REIDI tax regime, zero import duty and locational bonuses. The PDE signals 631 MW in 2028 and 6.6 GW in 2035: December’s auction should be the first of a series.
Accredited BNDES suppliers are detailed in the BESS under FINAME edition.
Methodology, sources and limitations
How this panel was produced
Consolidation of open data from ANEEL (Generation group: SIGA of Sep 1, 2026, RALIE of Sep 18, 2026, permit acts and distributed generation of Sep 29, 2026), ONS (constrained-off restrictions Jan 2024–Sep 2026, thermal generation by dispatch reason, variable unit cost, marginal cost, balance and turbinable spillage), CCEE (InfoMercado nos. 222, 228 and 229, spot price and contracts) and EPE (PDE 2035, approved by MME Ordinance 923/2026, and storage-auction documents). Data as of September 29, 2026.
About the charts: table figures are those of the study. Where the study only had a chart and no table, values were read from the original image and are marked as approximate; monthly curtailment was reconciled to ONS annual totals, and 2025 spot-price averages match the study.
Limitations
- Constrained-off data cover Type I, II-B and II-C plants; solar for May–Dec 2024 uses a proxy; 2026 data are subject to ONS revision.
- CCEE data were transcribed from the official CSV readings; regulated contracts by source are not available in open format.
- Submarket in SIGA was mapped by state, and distributed generation is outside SIGA totals.
- Sizing and the illustrative case are heuristics with stated assumptions: 55% utilization, 85% capture, PDE CAPEX, ABSAE fixed revenue and an exchange rate of R$5.40.
- Quantity, price and qualified bidders for the storage auction had not been published as of Sep 29, 2026.
Main sources
- ANEEL · Open Data, Generation group · SIGA · RALIE · MMGD
- ONS · constrained-off restrictions · Open Data · RT DGL-ONS 0189/2025
- CCEE · market data and InfoMercado · auctions
- EPE · PDE 2035 · 2026 storage LRCAP
- MME · Normative Ordinance 136/2026 · Law 15,269/2025 · ANEEL REN 1,030/2022
- BNDES · CFI accreditation for the 2026 LRCAP
Study EST-GER-001/2026, rev. 0, September 29, 2026, with 30 references. The full source list, including industry studies and news on the cases cited, is in the study.
The full study
The consolidated executive study (29 pages), the source reports for wind, solar, hydro, thermal and biomass, and the workbook with the processed data and the opportunity model (60 tabs) are sent to anyone who asks at amatiri@amatirienergia.com.br. Free to use, with attribution to Amatiri Energia and the original sources.
To assess storage or flexible load at a plant, see What we do.
Amatiri Energia is an engineering and regulatory advisory firm for the power sector, registered with CREA, the Brazilian engineering council, under corporate registration 2543985. Every deliverable is issued with a registered ART, the Brazilian engineering technical responsibility record, and a named engineer of record. This page is not an investment recommendation.
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