Bifacial model feature only adds +2-3% extra production

[Adam Bell]

Hello, I made a very very simple system, using the ZNshine 450W bifacial PV module.

 

I wanted to see how much extra production the bifacial side adds.

 

So I ran the model with and without the bifacial model. The difference is less than 3% production?

 

I followed the PVSyst guide to model bifacial systems. Can anyone explain why the bifacial model only adds ~3% production?

 

 

[dtarin]

It is due to your model. What is your albedo and other bifacial settings like height from ground? Where is the project located, what is the GHI? You have a 78% GCR, which is extremely high, and your tilt is only 10 degrees. You will not see a high bifacial gain with that design. 

Edited June 10, 2022 by dtarin

[Adam Bell]

Thank you, that would make sense. Also, it is San Jose California. I attached the GHI graph screenshot

I was also wondering if, in the system tab, I should double the number of strings because I am using "Twin Half-cut cells" modules ?

And if I should activate "Electrical Effect" in orientation tab? Selecting that lowers the production slightly ~2%

I selected the default 0.30 albedo, and the height is 2 ft (0.61 m ) from the ground.

Thank you!

[dtarin]

Twin half-cell does not double the number of strings, it halves the modules. You still have only one module supplying power. You should use electrical effect. 30 albedo is high. Is the roof white? 

[Adam Bell]

I am sorry for the late reply. I realized after the fact what a silly question it is to double the strings. And yes, I included the electrical effect by defining two strings, the cell width as approximately 8cm. Yes the roof should be white, its that typical membrane covering on commercial roofs.

[dtarin]

Typical cell width range is 15.6cm to 21cm.

[Adam Bell]

Correct, these are half cells