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Solar array energy budget
Estimate energy from array rating, equivalent peak-sun hours and supplied derating.
A clear answer. Here’s how.
Estimated kWh/day=total rated watts×equivalent peak-sun hours×derating/1000. Multiplies by the supplied number of identical-condition days. Peak-sun hours represent integrated irradiance, not daylight duration. No weather/location API is used; orientation, shading, temperature, inverter/storage losses and seasonality must be represented in your assumptions.
See a worked example
Worked example
A fixed demonstration, separate from the values you enter above.
- Nominal rating per panel (W)
- 400
- Number of panels
- 6
- Equivalent peak-sun hours per day
- 4
- Delivered-energy derating factor (%)
- 80
- Days at the same assumed conditions
- 30
Example result
- Array nominal rating (W)
- 2,400
- Estimated daily energy (kWh)
- 7.68
- Energy over supplied days (kWh)
- 230.4