On 9 November 2026, ANEEL's technical areas presented a plan to replace Brazil's optional tarifa branca with the Tarifa Hora Certa. Low-voltage consumers in groups B1 (residential), B2 (rural) and B3 (commercial, industrial and other activities) that use 500 kWh or more per month would move to time-of-use billing automatically, in three stages up to 2031, according to ANEEL. The proposal still needs a vote by ANEEL's board, which Canal Solar reports is expected by December.

For shops, small factories, farms, solar owners and EV charging operators, this changes the value of every kilowatt-hour used in the evening. This guide explains the new rules, puts numbers on the peak-price gap and shows where a battery pays back.

What is the Tarifa Hora Certa?

It is a time-of-use tariff with three price periods on weekdays and one cheap price at weekends. Peak lasts three consecutive hours, usually in the early evening.

Exact hours and prices will differ by distribution company. ANEEL plans to review each distributor's tariff design, and its notice says some areas could get a cheaper period during the hours of strongest solar generation.

Who moves to the new tariff, and when?

The biggest low-voltage users move first. Each stage starts in April, after at least three "informative" bills that show what the customer would have paid.

Figure 1. Proposed rollout. Sources: ANEEL, Canal Solar.

Customers who don't want time-of-use can switch to a temporary flat tariff, but it costs more than today's conventional tariff. Canal Solar reports ANEEL's estimate of 3% to 5% above the conventional price, and the option lasts only two years from the start of each stage.

How big is the peak-price gap?

In ANEEL's example using Cemig data, peak energy costs more than twice the off-peak price. That gap is what a battery earns from.

Figure 2. Source: ANEEL survey based on Cemig Distribuidora data, as reported by Primeira Hora. Prices vary by distributor.

In this example, off-peak energy is about 17% cheaper than today's conventional price, while peak energy is about 92% more expensive. A business that can't move its evening load will pay more. A business that moves it, or covers it from a battery, will pay less.

How much does a battery save per kWh?

About R$0.90 for every kWh moved from off-peak to peak, using the Cemig prices and a 90% efficiency assumption. That adds up to roughly R$224 per kWh of usable battery capacity each year.

Table 1. Energy arbitrage under the Tarifa Hora Certa. Jingye estimate, before O&M, taxes and degradation. Prices from the ANEEL/Cemig example above.

Example: one LFP-261kWh cabinet

Our LFP-261kWh all-in-one cabinet has 261 kWh of usable capacity and a built-in 125 kW PCS. Over a three-hour peak it could deliver up to 375 kWh at full power, so energy, not power, is the limit: it covers 261 kWh of peak load each weekday.

• Annual saving: 261 kWh × R$0.90 × 250 days ≈ R$58,500 per year (Jingye estimate)
• Indicative installed cost: Greener's Brazil benchmark for a 500 kW / 1 MWh system is BRL 1.73/Wh in 2026, or about R$452,000 for 261 kWh
• Simple payback on arbitrage alone: about 7.7 years (Jingye estimate)
• Cycle use: 250 cycles a year is 2,500 cycles in 10 years, well inside the cabinet's rated cycle life of more than 6,000

What does it mean for solar owners?

Solar produces at midday, but the expensive hours are in the early evening. Under time-of-use billing, solar alone no longer covers the most costly part of the bill.

ANEEL's proposal brings distributed-generation units into the Tarifa Hora Certa when they consume or inject 500 kWh/month or more on average over 12 months. Existing systems keep an exit option during the transition, but from 2033 the rule becomes mandatory for existing units too, including GD1 systems, Canal Solar reports. New net-metering connections filed 90 days after publication have no exit at all.

A battery lets a solar owner store midday output and use it during the three peak hours. For installers and EPCs, that means quoting solar + storage as one package for any client above the thresholds, starting with the 1,800 kWh/month group in 2028.

What does it mean for EV charging stations?

New commercial charging stations would be on the Tarifa Hora Certa from day one, so evening charging sessions would cost the operator the peak price.

Figure 3. ANEEL's illustrative example, as reported by Canal Solar.

ANEEL treats EV charging as a flexible load that can move to cheaper hours. That works for fleets parked overnight. It doesn't work for a public fast-charging site where drivers arrive after work. A battery at the site can charge off-peak and supply the evening sessions, so the operator sells peak-hour charging without buying peak-hour energy.

1. Get the tariffAsk your distributor for its Hora Certa peak hours and prices.
2. Measure peak loadLog kWh used in the 3 peak hours on weekdays.
3. Size the batteryMatch usable kWh to that peak energy, not to total daily use.
4. Add solar chargingCharge from midday solar where you can.
5. Check the paybackUse your own prices in the Table 1 method.
6. Install before 2028Be ready before the informative bills start.

Not sure whether your site needs a built-in or a separate PCS? See our guide to all-in-one vs separate PCS energy storage systems. For grid-scale projects, read our analysis of Brazil's LRCAP 2026 battery auction.

Frequently asked questions

Hebei Jingye New Energy Technology Co., Ltd, part of Jingye Group, makes LFP energy storage cabinets, battery storage containers, DC fast EV chargers, commercial vehicle batteries and cell contact systems for customers worldwide.