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Survey by Aneel shows progress in inspections against unauthorized changes in solar systems and reveals a significant difference between suspicions, ONS estimates, and frauds already confirmed by distributors in the micro and mini distributed generation market.
The National Electric Energy Agency identified signs of irregularities in 59% of inspections conducted by distributors in micro and mini distributed generation systems, although the irregular power confirmed so far totals about 88 MW.
This volume represents only 0.31% of the total MMGD power registered in the country, which reveals a significant difference between the rate of problems found in inspections and the effectively proven impact on the electrical system.
The contrast gains weight because the National Electric System Operator estimated that the unaccounted power could range between 11.8 GW and 14.6 GW, a number much higher than the total already confirmed by field inspections.
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Published on June 22, 2026, the technical note by Aneel gathered information sent by distributors about actions against unauthorized changes in the technical characteristics of distributed generation plants connected to the grid.
Known in the sector as “solar tampering”, the practice involves expanding or altering photovoltaic systems without communication to the distributor and without updating the approved conditions, which can affect billing, regulatory control, and operation of the electrical grid.
Aneel’s inspection started from suspicious units
In the first round of analysis, Aneel consolidated data from 19 distribution concessionaires, which serve approximately 43 million consumer units and recorded about 22.7 thousand inspections up to that point.
Among the inspected units, approximately 13.4 thousand showed an increase in power without authorization, according to information associated with the regulatory agency’s technical note on the progress of inspections in the distributed generation segment.
Even so, the 59% percentage does not allow concluding that the same proportion of all solar systems in the country is irregular, as the inspections were directed at consumers previously selected as suspicious by the distributors.
In Aneel’s assessment, the data represents an initial step in combating unauthorized distributed generation, as not all distributors linked to large economic groups have initiated structured inspection programs.
Therefore, regulatory reading requires caution, as there is an important signal of irregularities among the inspected cases, but the effectively confirmed power remains small when compared to the total registered MMGD park.
How distributors identify the “solar theft”
To locate possible deviations, distributors have started using analytical models that compare observed generation with the expected generation of each photovoltaic system, considering authorized power, injected energy, and consumption history.
With this data cross-referencing, technical teams can identify units with behavior incompatible with the approved power, prioritizing on-site inspections in cases where the chance of unauthorized alteration appears more relevant.
Among the methodologies reported to Aneel, Neoenergia compares observed generation and installed power, while CPFL Energia developed a statistical analysis based on injected energy, historical consumption, and registered power in the connection process.
Equatorial reported using tools that combine commercial and operational data, while Energisa started relating generation, approved power, and solar irradiation levels to guide inspections.
In other distributors, monitoring includes load curves, registration audits, images, billing records, and automatic alerts whenever injected energy exceeds limits compatible with the authorized power.
Field inspections verify installed equipment
After electronic screening, distributors conduct on-site inspections to verify modules, inverters, and other installed equipment, comparing the structure found at the consumer unit with the project originally approved for network connection.
In the procedures reported to Aneel, companies mentioned photographic records, issuance of inspection terms, and in some situations, the use of drones to check roofs or areas of difficult technical access.
When irregularity is confirmed, measures may include notifying the consumer, a deadline for regularization, billing review, disregarding irregularly injected energy, and suspension from the Electric Energy Compensation System.
In practice, the inspection seeks to prevent units expanded without authorization from receiving energy compensation under conditions different from those approved, avoiding distortions in network control and the treatment given to consumers.
Technical proof still limits the fight against fraud
Even with the advancement of analytical tools, the technical note points out difficulties in expanding oversight, especially because a large part of the installations only measures the net energy injected into the grid, not the gross generation.
This limitation makes it difficult to administratively prove irregular power increases, mainly when the distributor does not have direct access to the inverters or detailed data on the generation produced by the photovoltaic system.
Other obstacles include physical access to consumer units, inspection of hard-to-reach rooftops, restrictions on the use of drones, and operational difficulties in areas with public safety issues.
Without mass memory meters or equipment capable of recording more detailed information, the robustness of the evidence is reduced, which can influence processes of regularization, billing, or consumer disputes.
Despite these limitations, Aneel assesses that there is convergence among distributors in the use of data intelligence, targeted inspections, and standardized procedures to identify unauthorized expansions in solar systems.
Distance between ONS estimate and confirmed frauds
The survey puts the “solar theft” on the regulatory radar, but it still does not offer a complete picture of the sector because it depends on the expansion of inspections and the comparison between methodologies adopted by the concessionaires.
In this scenario, the difference remains between the ONS estimate for unaccounted distributed generation and the volume of irregularities already confirmed in the field by the distributors participating in the survey.
This gap should guide new discussions on monitoring, oversight, and legal security in micro and mini distributed generation, especially in systems where the distributor cannot accurately prove the gross generation.
The question now is whether the next steps will bring the inspection numbers closer to the operator’s estimate or confirm that the proven impact of the “solar theft” remains limited within the Brazilian MMGD?
