Solar system size calculator for Brazil
Enter the monthly consumption and the location to size a grid-tied photovoltaic system with the peak sun hours of real Brazilian cities.
- Number of modules
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- Installed power
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- Inverter size (DC/AC 1.2)
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- Estimated generation
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- Peak sun hours
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- Approx. roof area
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Estimate with a performance ratio of 80% and modules of about 2.6 m². The final design depends on roof orientation, shading and the inverter's string limits.
How the calculation works
The system is sized to offset the consumption above the utility's minimum charge: kWp = (consumption − minimum) ÷ (30 × peak sun hours × 0.80). Monthly generation is kWp × peak sun hours × 30 × 0.80. The 0.80 performance ratio accounts for temperature, wiring, inverter and soiling losses typical of Brazilian installations.
Peak sun hours come from the irradiation database of more than 5,500 Brazilian municipalities used by the Silizium design tool, ranging from about 3.6 to 6.1 kWh/m² per day.
For the rules that govern how this energy is credited, see Grid connection & net metering in Brazil.
Frequently asked questions
How many solar panels do I need for 500 kWh per month in Brazil?
With an average of 5 peak sun hours and a three-phase connection, offsetting 400 kWh (500 minus the 100 kWh minimum charge) needs about 3.3 kWp — six 580 W modules. In the South, with fewer sun hours, the same consumption needs a larger system.
Why is the minimum charge subtracted?
Brazilian utilities always bill a minimum of 30, 50 or 100 kWh per month depending on the connection type, even when the system generates more. Oversizing to cover it does not reduce the bill.
What DC/AC ratio is used in Brazil?
Installers commonly load inverters with 1.0 to 1.3 times their AC power in modules; 1.2 is a typical value for residential systems.