Compare results obtained with NSRDB data to data from different source

Hello,

I have just run my first simulation using the PVWatts performance model to characterize the solar potential of three locations in Canada. Basically I'm intrested in very general variables like Annual AC energy per year and the energy yield per year. I am asked to confirm these values by running the same simulation using data from another source than NSRB, like NASA for example. I was wondering whether there is a way to do this. I obtained the NASA data from the POWER Data Access Viewer here:

power.larc.nasa.gov/data-access-viewer/

The proposed downloadable parameters related to solar energy on this website are the following:  All Sky Surface Shortwave Downward Irradiance, Clear Sky Surface Shortwave Downward Irradiance, All Sky Insolation Clearness Index, All Sky Surface Longwave Downward Irradiance, All Sky Surface Photosynthetically Active Radiation Total, Clear Sky Surface Photosynthetically Active Radiation Total, All Sky Surface UVA Irradiance, All Sky Surface UVB Irradiance, All Sky Surface UV Index. 

Can I use some of these parameters to create an input csv or txt file to SAM and calculate yearly Annual AC energy and energy yield? I apologize for the long post, I was aiming for clarity ...

Thank you very much!
Ege


 

Hi Ege,

You can use weather and solar irradiance data from any source in SAM. Please see the following topics in SAM's Help system for information about what data you need, and SAM's weather file format:

samrepo.nrelcloud.org/help/weather_data_elements.htm

samrepo.nrelcloud.org/help/weather_format_sam_csv_solar.htm

Best regards,
Paul.

Thank you very much Paul, I missed those references somehow. I will give it a try.

Best,
Ege 

Hi Paul, 
I managed to create a csv file that SAM can process, but this is using NSRDB data. I have also created one with data from another source - which to me is exactly the same as the first one except for the values - but this one doesn't work. The error I get is 

exec fail(pvwattsv8): CSV: data line formatting error at record 8736
Simulation pvwattsv8 failed :exec fail(pvwattsv8): CSV: data line formatting error at record 8736
gen not assigned
Simulation grid failed :gen not assigned

I don't understand what is special about record 8736. I thought maybe you could quickly spot something that I overlooked. Included are the working csv file, the problematic one and a printscreen of the error.

Thank you very much!
Ege

Hi Ege,

This problem is caused by the leap day (February 29) in your file and missing data for December 31. SAM expects the file to contain a complete year, with data for January 1 through December 31. It should handle a file with data for February 29 by ignoring it, but we recommend removing data for that day so you can be sure of the data SAM is using.

Best regards,
Paul.

Thank you so much Paul, that did the trick. 

Best regards,
Ege