the effect of cloudy weather on the energy production of a photovoltaic system

Hi!
To analyze the effect of cloudy weather on the energy production of a photovoltaic system — either within the parametric analysis section or any other module — which input variable should be used?
I could not find a direct parameter for this purpose, so I would appreciate your guidance.

Best regards
Samin Roshan

Hi Samin,

In SAM, the effect of weather on the production of a PV system is determined by the data in the weather file. SAM's PV performance models require a weather file with information about the solar irradiance, ambient temperature, and wind speed. The solar irradiance data in the file accounts for the effect of clouds: The daytime direct normal irradiance (DNI) is less on a cloudy day than a clear day.

To see the effect of clouds on the system's performance, you could compare the electrical output of the system on a clear day with the output on a cloudy day. You can use the "Irradiance DNI from weather file (W/m2)" and "System power generated (kW)" output variables to see this effect. For example, this plot shows two clear days followed by two cloudy days:



Best regards,
Paul.