Mismatched Annual Generation Numbers

Hi all,

I am running a simulation through two different financial models via PySAM: the single owner model and the third party financial model. With both financial models I am using PvWattsv8, Grid, and Utility Rate 5. I am seeing a discrepancy in the annual energy generation and I was wondering if anyone had an explanation. 
Essentially, I am printing out the output from the PV (system) model for annual energy generation (in both financial simulations) -  "Annual Energy": system_model.Outputs.annual_energy". However, the numbers are different. I would understand if I was printing out an output from the financial models, as that is the only thing that is differing from the code, however shouldn't any outputs from the system model be the same regardless of what financial model I am using? The order of model execution is the following: 
system_model.execute(1)
 grid_model.execute(0)
 utility_rate.execute(0)
 total_installed_cost = installed_cost(system_model.SystemDesign.system_capacity) *this is from the total installed cost fn I created* 
 [whatever financial model].execute(0)
I am not an expert at coding and only have recently delved into PySAM so any advice and guidance would be much appreciated!

Hi Sanjana,

The 'annual_energy' variable is an an output of the Pvwattsv8 module:

nrel-pysam.readthedocs.io/en/main/modules/Pvwattsv8.html#PySAM.Pvwattsv8.Pvwattsv8.Outputs.annual_energy

It is an INOUT variable for the Grid module, so its value may be changed by the module:

nrel-pysam.readthedocs.io/en/main/modules/Grid.html#PySAM.Grid.Grid.SystemOutput.annual_energy

Best regards,
Paul.