PVGIS optimization vs PVSyst optimization

[Emi]

Goodmorning everyone!

I just tried to use PVGIS "optimize slope and azimuth" and then use PVSyst "Optimization tools", running a simulation to find the best tilt and azimuth using Meteonorm (PVGIS import doesn't work at now).

The results of two tools are significantly different.

The site is in Geneva.

Any idea?

Maybe is it due to different database ? 

Many thanks

Images following:

 

[dtarin]

Batch simulating with different tilt and azimuth will provide more accurate results. 

[Emi]

Thanks for your suggestion,

but I tried for several sites and optmization tools always returns -5° best azimuth...

Why? Anything wrong?

Please, take in account horizon is flat...

With this behaviour optimization tool is useless

Edited 3 hours ago by Emi