Pvwatts with user defined POA Irradiance

3 posts / 0 new
Last post
Pvwatts with user defined POA Irradiance


I´m currently trying to run the PvawttsV5 module from Excel (using the VBA Generate Code Option), and would like to know if it is possible to use my own P.O.A. Irradiance Values as input.
I see from the SSC SDK tool that it was a possibility in pvwattsv1 (user_poa), however i do not see it as an input variable in this latest version.
If this isn´t possible, can I use the Generate Code Option for a specific module of SAM? If I understand correctly the Generate Code option assumes the selected performance model, is there a way to override this so I can select a Pvwatts version that will take POA?

Thanks in advance for your help!

Miguel Duarte

Paul Gilman

Dear Miguel,

The enable_user_poa option is not available for the pvwattsv5 compute module. That was probably an oversight when we developed the new module. I have added that as a requested new feature for a future version.

In the meantime, you can use POA irradiance as input to the pvsamv1 module. To do that set irrad_mode = 3 for POA irradiance data measured using a reference photovoltaic cell, or irrad_mode = 4 for POA data measured using a pyranometer. Then, add a "POA" column to a weather file formatted using the SAM CSV Format containing the POA data. The model will then ignore any other irradiance data in the file, and use your POA data as input to the module model.

Best regards,


Hello Paul,

Thank you very much for the swift reply & explanation, and also for taking this option into consideration for future versions.

Kind regards,

Theme by Danetsoft and Danang Probo Sayekti inspired by Maksimer