You need about 52 solar panels to generate 2000 kWh per month.
This assumes that use of 320 W-rated solar panels mounted optimally at a location that receives on average 4 hours of sunshine a day.
What determines solar panel energy (kWh) output?
In addition to the power rating of solar panels (W) and the average number of sunshine hours, the actual number of solar panels that generate a specified number of kWh depends on the factors below:
# 1. solar panel efficiency: Solar panels with a higher efficiency rating generate more energy.
Premium high-efficiency solar panels at 19% though more expensive will generate more power than the standard solar panels at 17% efficiency.
# 2. solar panel tilt: Solar panels have to be tilted at the optimum angle at installation in a specific location to receive the expected average peak sunshine hours.
# 3. solar panel temperature: The amount of power generated by solar panels is affected by how hot the solar panel is.
The hotter a solar panel is the lower the amount of power generated (surprising)!
This can help explain the dips in the amount of energy generated by your solar system on extremely hot days.
Sufficient space between the solar panels and roof needs to be provided at installation for air circulation to minimize the solar panels heating up in hot weather.
# 4. solar panel age: Solar panel capacity degrades over time.
A solar panel loses an estimated 1% of its capacity every year.
Based on this, a 5 kWh system can be expected to reduce to 4.5 kWh (5-10%*5) after 10 years.
The table below provides an approximate number of solar panels needed to produce indicated number of kWh per month.
*Assumes 320W solar panels; 4 peak sun hours/day
| No. | kWh per month | No. of solar panels |
| 1 | 500 | 13 |
| 2 | 600 | 16 |
| 3 | 1,000 | 26 |
| 4 | 2,000 | 52 |
| 5 | 2,500 | 65 |
| 6 | 3,000 | 104 |
In addition to the table above, you can also use the calculator below to work out an approximate number of solar panels that generate a specified number of kWh per month.
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