Modeling Bifacial Panels at 90° tilt 90° azimuth

Hi, first time forum poster here!

I'm having difficulty modeling my 15MWdc vertical bifacial agrivoltaic project in SAM. The simulation returns generation values much too high, with capacity factors over 45%. I would expect a capacity factor of around 15% for a bifacial module in this orientation in a 5.0kWh/day region, given a bifaciality factor of 70% and no shading.

If I uncheck the "bifacial module" box, the simulation returns a capacity factor of around 8%, which is realistic. I can also force the system to model the bifacial installation by making two sub-arrays, the second with 270° azimuth and only 70% as many modules, but this is of course not ideal.

I included my SAM project file. Thanks!
-Nick

Hi Nick,

SAM's bifacial model was developed based on measured data for modules with tilt angles of 15, 25, 35 and 45 degrees. We are investigating its suitability for modules with higher tilt angles: github.com/NREL/SAM/issues/1151 .

See this similar topic on the SAM forum: sam.nrel.gov/component/kunena/forum-general/3468

And this issue on GitHub: github.com/NREL/SAM/issues/1151

Best regards,
Paul.

Paul,

Thank you! I did a forum search before posting and somehow didn't find the earlier thread. I'll follow its recommendations.

-Nick