Photovoltaic Efficiency Calculator Formula
Understand the math behind the photovoltaic efficiency calculator. Each variable explained with a worked example.
Formulas Used
Net Daily Output
net_daily_kwh = gross_daily * (1 - system_losses / 100)Net Annual Output
net_annual_kwh = gross_daily * (1 - system_losses / 100) * 365Gross Daily Output
gross_daily_kwh = gross_dailyVariables
| Variable | Description | Default |
|---|---|---|
irradiance_kwh_m2 | Daily Solar Irradiance(kWh/m²/day) | 5 |
panel_area_m2 | Total Panel Area(m²) | 30 |
module_efficiency | Module Efficiency(%) | 20 |
system_losses | System Losses (wiring, inverter)(%) | 14 |
gross_daily | Derived value= irradiance_kwh_m2 * panel_area_m2 * module_efficiency / 100 | calculated |
How It Works
Solar Panel Electrical Output
A photovoltaic (PV) system converts sunlight into electricity. The actual output depends on available irradiance, panel efficiency, and system losses.
Formula
Gross Output (kWh/day) = Irradiance (kWh/m²/day) x Area (m²) x Efficiency
Net Output = Gross Output x (1 - System Losses)
System losses include wiring resistance, inverter conversion, soiling, and temperature derating. Typical total losses are 10-20%.
Worked Example
A 30 m² array with 20% efficient panels, 5 kWh/m²/day irradiance, and 14% system losses.
irradiance_kwh_m2 = 5panel_area_m2 = 30module_efficiency = 20system_losses = 14
- 01Gross output = 5 x 30 x 0.20 = 30 kWh/day
- 02Net output = 30 x (1 - 0.14) = 30 x 0.86 = 25.8 kWh/day
- 03Annual output = 25.8 x 365 = 9,417 kWh/year
Ready to run the numbers?
Open Photovoltaic Efficiency Calculator