A ANEEL (National Electric Energy Agency) maintained the restriction that allows a consumer to inject energy produced by a 75 kW solar system into the Cemig grid only between 19 pm and 5 am. The condition was established by the distributor after a study identified a reversal of power flow in the electrical grid.
The decision is noteworthy because photovoltaic generation occurs during the day. Without a storage system, authorization to export energy only at night is, in practice, equivalent to preventing the plant's surplus energy from being sent to the grid.
The case involves a consumer unit located in the municipality of São Francisco, in Minas Gerais. The decision is part of the 14th Ordinary Deliberative Circuit of the Board of Directors of... ANEEL.
The restriction does not mean that the consumer is obligated to inject energy during the night. The condition presented by Cemig establishes that the export to the grid can only occur during that interval.
During the day, solar energy can still be used to meet the unit's immediate consumption. However, to prevent surplus energy from reaching the grid, the consumer can reduce the plant's power output or resort to energy storage.
Consumer disputed Cemig's quote.
Cemig submitted the connection quote in August 2023. Upon reviewing the request, the distributor identified that the microgeneration system's connection would cause a flow reversal at the transformer station or feeder line. The consumer questioned the basis of the studies and requested a review of the conditions.
In February 2026, the SMA (Superintendence of Administrative Mediation and Consumer Relations) denied the request. Faced with this decision, the consumer filed an administrative appeal, arguing that the connection quote and the Agency's statement were not properly substantiated.
The Board of ANEELHowever, the technical area's understanding was upheld, and the appeal was denied. Therefore, the conditions established in Cemig's connection budget remain valid.
The process does not specify how much the network reinforcement works would cost, which alternatives were discarded by Cemig, nor the investment needed for solar energy to be injected during the day.
The restriction is stipulated in the regulations.
The decision was based on Article 73 of Normative Resolution No. 1.000/2021. According to the rule, when the connection of micro or mini-distributed generation causes a flow reversal, the distributor must carry out studies to identify alternatives capable of eliminating the problem.
Among the solutions foreseen are:
- Circuit reconfiguration and load redistribution;
- Connecting the generator to another circuit;
- Connection at higher voltage level;
- Permanent reduction of injected power;
- Limiting injections to specific days and times;
- Dynamic control of exported power.
In the case analyzed, Cemig concluded that injection between 19 PM and 5 AM would be the technically viable alternative to eliminate flow reversal. The STD (Superintendence of Regulation of Electricity Transmission and Distribution Services) considered that the study met the regulatory requirements.
The Federal Prosecutor's Office attached to ANEEL It was also understood that there were no legal irregularities in the procedure. Upon analyzing the process, the ANEEL He stated that his role in handling individual complaints is limited to verifying whether the procedures adopted by the distributor comply with regulations.
According to the Agency, it is not the regulator's role to replace the concessionaire in the preparation or review of technical connection studies. ANEEL It also concluded that the consumer's appeal did not present new facts or technical or legal arguments capable of overturning the conclusions of Cemig and the Agency's technical areas.
all the content of Canal Solar is protected by copyright law, and partial or total reproduction of this site in any medium is expressly prohibited. If you are interested in collaborating or reusing part of our material, please contact us by email: redacao@canalsolar.com.br.
Comments (17)
Comments are moderated before publication.Comments should be respectful and contribute to a healthy debate. Offensive comments may be removed. The opinions expressed here are those of the authors and do not necessarily reflect the views of the author. Canal Solar.
The focus is on buying energy from the Chinese companies that invested in hydroelectric and thermoelectric plants here, that's what it's all about. Solar power generation will become increasingly difficult in this shitty country that's only big in size and minuscule in everything else.
Brazel, my friends.
The day there's no generation left, they'll change that law in no time.
This country is a disgrace; people invest in solar roof tiles to save money and... ANEEL It supports companies that get richer and richer while we, who receive a pittance, have to pay exorbitant electricity bills. This is a country of thieves.
The average citizen always gets the short end of the stick. It's better to think about a fair sizing of their own generation and implement it off-grid.
Brazil is a truly special country. Everyone is moving towards clean energy, and Brazil is going in the opposite direction, blocking and shutting down solar power plants. But when it comes to thermoelectric plants that consume huge amounts of fossil fuels and contribute to pollution, making energy more expensive for Brazilians but benefiting only a few, there are no problems or cuts to these expenses. That's what happened in the government's energy auction, with a group that bought a thermoelectric plant to participate in the auction. It's incredible how our country works.
This proves that what the government really wants is to collect more and more money. It's no use for citizens to create ways to save money. They always have to pay; for someone to travel the world spending public funds!!!
Good morning, how do I export the energy that small users of the 75KW system generate only during the day? And those who use storage use it for their own consumption.
In my case, I export surplus consumption. It doesn't make technical sense, I think it's absurd!!!!
I'm thinking of investing in a 75kW power plant. What are the additional costs associated with storing energy in batteries during the day and recharging at night?
Additional value?
Is there any government incentive for this plan?
Buy a good battery pack and go be happy! Tell the regulator to go to hell! When I finish my project, it will be off-grid!
I recommend buying a battery pack, storing it during the day, and injecting fuel at night. The system will need a hybrid inverter!
Given the size of the building, the guy has money; buy some batteries and disconnect the power lines, problem solved. Off-grid, the cry of liberation from distributed generation.
In this country, robbing law-abiding citizens is already an institutionalized practice. The best solution to this corruption is to install an off-grid system and disconnect the meter. Technology has increased the lifespan of batteries for self-storage of energy. I want to see what they'll do when they have no one to sell the energy to. Turn off the sun? I think that's unlikely.
That's absurd. If the distributor's electrical system cannot absorb 75 kW of power, this means that its system is at its nominal limit. In other words, there is no expansion or reinforcement of the network.
The solution would be to have a hybrid system, because in addition to the cost of the B wire, there is the impracticality of injecting energy into the grid. I believe that there is still a lot of misinformation at the time of design, and also because of the high cost of the hybrid system due to the batteries.
So she should have had an analysis done by Cemig before installing the solar panels, right?
Now it would be better to increase the investment and install an off-grid system so that one day we can recoup the investment, right? Cemig doesn't object to off-grid systems in this case, right?
A report from an electrical engineer contesting and demonstrating whether reversing the flow is possible without damaging Cemig's system was missing.