Input data:
Latitude, Longitude = 31.785, -106.495
Time Zone = - 7
Weather data
Inverter: 1 units Sungrow SG3600UD
ILR = 1.1
Row to Row = 20 ft
PVFARM Result I
Taking into account:
Shading
Incidence angle (IAM) losses
Soiling losses
Bifaciality
Thermal losses
Spectral correction
Module quality losses
Mismatch losses
DC ohmic wiring losses
Inverter loss during Efficiently
Inverter loss during over/under inverter voltage and current
Inverter loss due to overpower
For Solar Module: 7 209 units LR5-72HBD-550M we get:
Produced Energy: 9 454 MWh/year
Specific Production: 2 384 Wh/W/year
Performance Ratio: 80.59 %
PVsyst Result I
Taking into account the same factors:
For Solar Module: 7 209 units LR5-72HBD-550M we get:
Produced Energy: 9 487 MWh/year
Specific Production: 2 393 Wh/W/year
Performance Ratio: 80.01 %
Error PVFARM vs PVsyst < 1%
PVFARM Result II
For Solar Module: 8 232 units FirstSolar FS-6480A we get:
Produced Energy: 8 894 MWh/year
Specific Production: 2 251 Wh/W/year
Performance Ratio: 76.03 %
PVsyst Result II
Taking into account the same factors:
For Solar Module: 8 232 units FirstSolar FS-6480A we get:
Produced Energy: 9 231 MWh/year
Specific Production: 2 336 Wh/W/year
Performance Ratio: 78.2 %
Error PV Farm vs PVsyst = 3.6%
Note: This difference is mainly due to temperature losses because PVsyst calculates the dependence of power on temperature using its own empirical methodology. PVsyst can obtain a power temperature coefficient different from the manufacturer's specification.
PVFARM directly uses the temperature coefficient of power from the manufacturer's specifications to calculate power versus temperature.
PVFARM vs PVsyst
When taking into account additional important factors in PVsyst (they are not in PVFARM):
Electrical Losses due Shadings
AC ohmic wiring losses
Transformer loss
For Solar Module LR5-72HBD-550M we get:
PVFARM Result (the same as Result I)
Produced Energy: 9 454 MWh/year
Specific Production: 2 384 Wh/W/year
Performance Ratio: 80.59 %
PVsyst Result
Produced Energy: 8 982 MWh/year
Specific Production: 2 265 Wh/W/year
Performance Ratio: 75.90 %
Error PVFARM vs PVsyst = 5.3%
Note: Electrical Loss due to shading makes the greatest contribution to losses. We carried out calculations in Pvsyst Electrical Losses due to shading using “Detailed calculation, according to Module Layout”. This option can be used for Layouts no larger than 5MW. But it gives a more accurate result compared to the "According to module strings" option. The "According to module strings" option does not take into account the connection of submodules via bypass diodes and gives an overestimated loss value.
