Hi Caitlin,
Yes, that is correct. SAM calculates the incident irradiance (or plane-of-array, POA irradiance) as described in Chapter 6 of the SAM Photovoltaic technical reference manual.
Gilman, P.; Dobos, A.; DiOrio, N.; Freeman, J.; Janzou, S.; Ryberg, D. (2018) SAM Photovoltaic Model Technical Reference Update. 93 pp.;
NREL/TP-6A20-67399. (
PDF 1.8 MB
)
The bifacial model calculates the backside irradiance as described in the paper you referenced:
Marion, B.; MacAlpine, S.; Deline, C.; Asgharzadeh, A.; Toor, F.; Riley, D.; Stein, J.; Hansen, C. (2017). A Practical Irradiance Model for
Bifacial PV Modules. NREL/CP-5J00-67847 (
PDF 1 MB
)
Note that the SAM PV reference manual was published before the bifacial model was implemented in SAM.
Best regards,
Paul.