Brazilian solar entrepreneurs accuse Cemig of hampering new DG connections

Brazilian pressure group the free solar movement (Movimento Solar Livre, MSL) is accusing Minas Gerais state power distribution utility Cemig of arbitrarily preventing consumers in its concession area from generating their own energy by installing solar panels for distributed generation (DG).

MSL, which says it represents “solar entrepreneurs”, also accuses the distribution company of having unilaterally changed the way in which microgeneration credits are offset against customers' bills. 

DG involves consumers producing power for their own consumption via small (micro and mini) generating units installed at or near consumption points, using renewable energy sources. For example, a home that has PV solar panels on the roof, or a pig farmer who installs a mini biogas plant.

The amount of power produced is deducted from the total consumption of the respective unit. The generator can also supply surpluses to the national grid in exchange for credits that can be used in up to 60 months.

According to MSL president Hewerton Martins, Cemig claims that its grid no longer has the technical capacity to accommodate new connections and that the risk of power flow inversion makes the installation of photovoltaic systems unfeasible. 

Flow inversion in the distribution grid occurs when the amount of energy generated by distributed generation systems exceeds the demand of consumers connected to the same grid.

“The arguments do not hold water. Minas Gerais companies in the sector depend on Cemig's approval to install clean energy sources in customers' homes, which has not been happening repeatedly due to this obstruction,” he said in a press release.

According to Martins, Cemig's failure to compensate distributed solar energy producers for their credits has also had a major impact on the income of those who have invested in DG. 

“These are people who have invested and have been injecting energy into the grid, citizens who have committed to financing and have had part of their income captured and are having to pay their energy bill in full,” said the MSL president. 

Martins added that Cemig's denials for small energy producers expose a conflict of interest, since the utility also operates large-scale DG, with sales of energy subscriptions by the company Cemig SIM.

Cemig said, via its press office, that it continues to make the connections normally, in accordance with Brazil’s electric power regulator Aneel's regulations, which emphasize the need to analyze the possible inversion of the flow of power for these connections. 

“If inversion of flow is found, Aneel determines the adoption of specific procedures to the benefit of all energy consumers, which Cemig fully complies with,” the company explained.

The concessionaire said that the process for delivering invoices for distributed generation has changed since May. 

“Now, after the meter reader takes the measurement and then immediately issues and delivers the document, the customer entitled to credits receives the amount allocated up to that date,” Cemig explained.  

On the other hand, the energy credit sent by the generator after the invoice has been delivered will be included in the invoice for the following billing cycle. 

“This is a practice provided for by the regulator and common among distributors. Therefore, customers will always receive all their credits, as has always been the case.”

Cemig emphasized that the new system guarantees greater security and provides the benefit of customers receiving their energy bill immediately after their meter is read, not implying any loss or credit burden for customers.

Since 2018, Cemig has connected more than 270,000 DG units, whose installed capacity in Minas Gerais state is approximately 8GW.