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Entry · Consumer

Availability cost

How much is owed even when injection exceeds consumption?

● checked against the primary source on Sep 30, 2026Source: ANEEL

Acronyms: ANEEL, Brazilian Electricity Regulatory Agency; TE and TUSD, Energy Tariff and Distribution System Use Tariff; REN, ANEEL Normative Resolution.

In one sentence

Amount in reais equivalent to 30 kWh (single-phase connection), 50 kWh (two-phase) or 100 kWh (three-phase) that ANEEL says is owed by low-voltage consumer units (group B), even when the energy injected into the grid exceeds consumption.

Synthetic example

Synthetic exampleHypothetical values, chosen for teaching. They are not observatory data and do not enter any indicator.

A single-phase residential unit with microgeneration injected more energy into the grid in a month than it consumed. Even so, it owes the availability cost: 30 kWh multiplied by the tariff of the class. With a hypothetical tariff of R$ 0.80/kWh (TE plus TUSD, without taxes), that would be R$ 24.00 for the month.

Why it matters

It sets the floor of the energy portion of the bill of low-voltage units. For the Tarifa Social, the ANEEL page states that consumption up to 80 kWh in the month is free even in three-phase installations.

How it is measured

In equivalent kWh, multiplied by the tariff (TE + TUSD) of the consumer unit's class.

Unit: equivalent kWh (30, 50 or 100) multiplied by the tariff, in R$

Not to be confused with

What cannot be concluded

  • The originating norm (REN No. 1.000/2021) could not be read: ANEEL's document archive blocked automated access. The detail by number of conductors and the rule for the Tarifa Social above 80 kWh were not checked in the text of the norm.

Related entries

In the learning paths

See in the panel

Official source

  • ANEELPage “Micro e Minigeração Distribuída” (captured on Sep 30, 2026) 

    In other words: every low-voltage unit pays at least the equivalent of 30, 50 or 100 kWh, depending on whether the connection is single-phase, two-phase or three-phase, even when it generates more than it consumes.

    Literal excerpt from the document
    Portuguese only“para unidades consumidoras conectadas em baixa tensão (grupo B), ainda que a energia injetada na rede seja superior ao consumo, será devido o pagamento referente ao custo de disponibilidade – valor em reais equivalente a 30 kWh (monofásico), 50 kWh (bifásico) ou 100 kWh (trifásico).”

  • ANEELPage “Tarifa Social” (captured on Sep 30, 2026) 

    Literal excerpt from the document
    Portuguese only“mesmo no caso de instalações trifásicas, existirá a gratuidade no caso de consumo até 80 kWh no mês”

Documents accessed and text checked on Sep 30, 2026.