Two weekends ago, the ONS (National Electric System Operator) activated, for the first time, an emergency plan to reduce generation from power plants classified as Type III.
A decisão chamou a atenção do mercado e gerou questionamentos sobre quais empreendimentos seriam afetados. Em um primeiro momento, parte dos agentes associou os cortes à MMGD (micro e minigeração distribuída).
With the clarification that the measure only involved Type III plants, another question arose: what differentiates these plants from MMGD plants, since both are connected to the distributors' networks?
Despite this similarity, the two modalities play different roles within the electricity sector and follow distinct operating rules.
What are the main differences?
While Type III power plants act as agents for energy generation and trading, serving consumers in the Free Market or distributors, distributed generation (DG) systems are installed by consumers who aim to reduce their electricity bill through energy credit compensation.
The Type III power plant group mainly includes small hydroelectric plants (PCHs) and biomass plants that sell energy in the regulated and free markets and are generally connected to the medium or high voltage networks of local distributors.
The MMGD category includes residential systems, small businesses, industries, rural properties, condominiums, and shared and remote generation projects.
Outra diferença importante está no porte dos empreendimentos. Embora não exista um limite de potência que caracteriza uma usina como Tipo III, esses projetos normalmente possuem capacidade superior à da MMGD, dependendo da fonte e da região onde estão instalados.
The MMGD legislation establishes power limits of up to 75 kW for microgeneration, and in the case of non-dispatchable sources, such as solar and wind, the limit is 3 MW, while dispatchable sources, such as hydroelectric and biomass, can reach 5 MW.
In summary, while Type III power plants are part of the electricity sector's generation structure and may be subject to operational actions determined by the ONS (National System Operator), distributed generation (DG) systems are geared towards self-consumption and, to date, have not participated in the emergency power cut plan implemented by the operator.
Although the ONS (National System Operator) does not directly control these power plants, the generation forecast data and daily monitoring of Type III power plants integrated into distribution networks must be consolidated and forwarded to the ONS by local distribution concessionaires, aiming at the correct load forecasting of substations.
Can MMGD systems be cut?
Essa é uma das dúvidas mais frequentes após a divulgação da operação. A resposta oficial do ONS é que o plano emergencial acionado não teve como alvo os sistemas de MMGD.
The cuts exclusively involved plants classified as Type III and were carried out through 12 distributors, which concentrate about 80% of these plants in the country.
They were: Celesc, Cemig, Neoenergia Coelba, Copel, CPFL Paulista, EDP Espírito Santo, Neoenergia Elektro, Energisa Mato Grosso, Energisa Mato Grosso do Sul, Equatorial Goiás, Neoenergia Pernambuco and RGE.
However, although the emergency operation exclusively affected power plants classified as Type III, the possibility of restrictions on distributed generation (DG) became part of the regulatory agenda of the electricity sector through Public Consultation No. 009/2026. ANEEL.
A iniciativa, baseada na Nota Técnica nº 148/2025, foi aberta para discutir medidas capazes de ampliar a flexibilidade operativa e reforçar a segurança das redes de distribuição diante do crescimento acelerado da geração distribuída no país.
Entre as propostas apresentadas está a possibilidade de corte física ou lógica da geração de sistemas de MMGD em situações específicas que possam comprometer a segurança e a confiabilidade do sistema elétrico, em caso de esgotamento de outras alternativas operacionais.
O tema tem gerado debates no setor por envolver diretamente consumidores e empresas que investiram em sistemas de geração própria. Ainda assim, é importante destacar que atualmente não existe autorização regulatória para que o ONS ou as distribuidoras realizem cortes na MMGD nos mesmos moldes da operação emergencial aplicada às usinas Tipo III.
As contribuições à Consulta Pública foram recebidas até 8 de junho. Encerrado esse prazo, caberá agora à área técnica da ANEEL Analyze the feedback submitted by industry representatives and prepare a consolidated technical note with recommendations to be submitted to the Agency's Board. To date, there is no definitive decision or new regulation published on the matter.
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