Solar Energy + Electric Car: The Most Economical Combination
Charging your electric car with solar energy is like fueling up with the sun. The cost per kilometer drops to cents, the carbon footprint goes almost to zero and the investment pays for itself in a few years. See the numbers and how to size the system for the reality of Paraná.
The equation that changes everything
An average electric car consumes between 15 and 20 kWh to cover 100 km. If you drive 1,000 km per month (an urban average), you need 150 to 200 kWh per month to fuel the car. A 2.5 kWp photovoltaic system — with 5 panels of 500W — generates that energy in Paraná with room to spare.
In other words: with an investment of R$ 10,000 to R$ 15,000 in solar panels, you can drive the electric car for free for 25 years (the average lifespan of the panels). Compare that with spending R$ 500-700/month on gasoline and the decision becomes clear.
Cost per kilometer: solar vs. grid vs. gasoline
| Energy source | Cost/kWh | Cost/100 km | Monthly cost (1,000 km) |
|---|---|---|---|
| Solar energy (after payback) | R$ 0.00 | R$ 0.00 | R$ 0.00 |
| Solar energy (amortizing) | ~R$ 0.08 | R$ 1.40 | R$ 14 |
| Electric grid (residential) | ~R$ 0.85 | R$ 14.40 | R$ 144 |
| Electric grid (public DC) | ~R$ 1.30 | R$ 22.10 | R$ 221 |
| Gasoline (flex-fuel car) | — | R$ 53.50 | R$ 535 |
The difference is staggering. Even compared with charging on the residential grid (already very cheap), solar energy reduces the cost by more than 90%. Against gasoline, the savings reach 97% after the solar system's payback.
Sizing: how much solar you need
The calculation depends on how much you drive per month and your car's consumption:
Simple formula
kWp needed = (monthly km x consumption kWh/km) / (peak sun hours x 30 x 0.8)
For Curitiba/Pinhais, the average is 4.2 peak sun hours/day. The 0.8 factor discounts system losses.
Practical examples for the Curitiba region:
| Monthly use | Energy needed | Solar system | Panels (550W) | Investment |
|---|---|---|---|---|
| 500 km/month | ~85 kWh | 1.0 kWp | 2 panels | R$ 5,000-7,000 |
| 1,000 km/month | ~170 kWh | 2.0 kWp | 4 panels | R$ 9,000-13,000 |
| 1,500 km/month | ~255 kWh | 3.0 kWp | 6 panels | R$ 13,000-18,000 |
| 2,000 km/month | ~340 kWh | 4.0 kWp | 8 panels | R$ 17,000-23,000 |
How it works in practice
Most people don't charge the car directly from the solar panels (that would require charging only during the day). What happens is ANEEL's energy compensation system:
- During the day: your panels generate energy and send the surplus to the Copel grid.
- At night: you charge the car with energy from the grid, using the credits generated during the day.
- Zero balance: at the end of the month, the energy generated offsets the energy consumed. You pay only the minimum charge (the availability cost).
It's simple, automatic and doesn't require a home battery (though having one improves efficiency). The inverter and the bidirectional meter do all the work.
With solar energy, every kilometer driven in the electric car is practically free. And every liter of gasoline you don't burn is a small victory for the planet.
Payback of the solar system dedicated to the EV
Consider the scenario of 1,000 km/month driven:
- Solar investment: R$ 11,000 (2 kWp system)
- Monthly savings vs. grid: R$ 130 (you stop paying R$ 144/month of energy for the car)
- Monthly savings vs. gasoline: R$ 535 (assuming you switched from a combustion car to electric + solar)
- Payback vs. grid: ~7 years
- Payback vs. gasoline: ~21 months
The real payback is usually faster, because the solar system also offsets part of the home's consumption — not just the car's.
Specific advantages in Paraná
- Favorable solar irradiation: despite being in the South, Curitiba and Pinhais have 4.0-4.5 peak sun hours/day — enough for good generation.
- Copel Net Metering: Copel operates with efficient energy compensation, without excessive bureaucracy.
- State incentive: Paraná exempts ICMS on energy generated by distributed microgeneration.
- Sector growth: Paraná is the 5th state in solar installations, with a strong ecosystem of installers.
- Climate: mild temperatures favor panel efficiency (panels perform better in the cold than in extreme heat).
Combining solar at home + fast charging on the road
The ideal scenario for the EV driver in Curitiba is:
- 80% of charges: at home, with solar energy, during the night (compensation credits).
- 15% of charges: at a shopping mall or work, with semi-fast AC, as a supplement.
- 5% of charges: at a fast DC charging station like Elektro Charge, for trips or emergencies.
This mix keeps the monthly mobility cost below R$ 50, even accounting for charges away from home.
For entrepreneurs: solar + charging station
If you're an entrepreneur thinking of setting up a charging station, the combination with solar energy is strategic. A 30-50 kWp system can supply a significant part of a DC charger's demand, reducing the operating cost and increasing the margin. Moreover, the image of sustainability attracts conscious customers — who are the majority of EV drivers.
Charge with clean energy
Elektro Charge in Pinhais is the benchmark fast DC charging station. 60 kW, CCS2, 24h.
View on Google Maps →
