Increase in energy yield with azimuth different than zero

[Rafael Santos]

Hi,

I performed simulations with different azimuth angles (-10 to 90 degrees, in 5-degrees steps) and surprisingly I got higher annual energy production with most of the azimuth angles that are different than zero (the project is located on the southern hemisphere).

Simulation with Azimuth=0°:

 

 

Simulation with Azimuth=40°:

 

Intuitively, I would think a 0° azimuth would always give me the higher energy yield, which apparently is not so...

Of course, the configuration is exactly the same, except for the azimuth. The modules are fixed, tilted 12°, and bifacial.

Best regards,

Rafael

[dtarin]

No electrical shading loss is showing. If these are bifacial c-Si, you'll want to include electrical effect (modeled according to strings) and then make the comparison. 

[Rafael Santos]

Thanks for the reply!

 

I performed another simulation with electrical shading losses (acc. to module strings, 100% fraction for electrical effect). Although the results are slightly different, the question remais, as I am still getting higher results for a 40° azimuth:

 

Azimuth: 0°

 

 

 

Azimuth: 40°

 

The main concern here is not the shading or any other losses, but the second line: "Global incident on coll. plane". This gain should be higher for a 0° azimuth.

Best regards,

Rafael

 

 

[Rafael Santos]

I just uploaded a .MET file containing clear sky radiation data instead of regular GHI, and ran a batch simulation changing azimuth angles, and the optimal azimuth angle was 0deg N, as expected!

So, the "problem" here is specifically the TMY. Altough at "normal" conditions (considering only the universe geometry) the optimal azimuth should be zero, some sites have specific climatology (tend to be cloudier at mornings or afternoons on certain months), and this may affect the optimal annual energy production, specially considering fixed-tilt modules.