Site II.1

Site ID
Nominal Capacity
48.8 kWp
Average Specific Yield
718 kWh/kWp
Total Estimated Loss
Possible Gain
20% to 25%
1.3 ₹/Wp, 0.8 ₹/Wp/a
Expenditure / Energy


The actual module tilt angle is deviated from the optimal angle of 10° leading to an estimated loss of 2.8%. From the safety perspective, the inverter does not include an overvoltage protection and isolation losses can’t be excluded due to the presence of scratches at the backsheet. The modules are hotspot sensitive and heavily affected by PID. It is recommended to: (i) reduce the module by at least 5°, (ii) implement an anti-PID solution and (iii) restring the system so that modules with similar tilt and azimuth are grouped together. The estimated production boost expected by the retrofitting actions lies between 20% and 25%.

Main Findings

No weather station has been installed and the Performance Ratio is not tracked.
The actual module tilt angles (7° and 25°), were found to be deviated from the optimal angle of 10°.
Scratches were observed on the back side of some modules.
Some connectors were found to be not tightly closed.
Cable ties broke hence the module cables and connectors were loosely hanging.
Some parts of the cables are exposed to UV radiation. Pipes conveying cables are brittle and some parts have already broken.
There is no overvoltage protection in the inverter room.
PID presence was confirmed via IR and EL inspections.

Impact on Performance

Heavy Soiling
Soiling measurements were conducted measuring both the short circuit current and nominal power before and after cleaning. The estimated soiling loss is on average 0.8%.
Estimated Loss
≈ 0.8%
Cell Cracks
The amount and type of cracks found in the selected modules during the electroluminescence inspection, reduce the nominal power of the PV plant by ca. 3%. This statement is based on the extrapolation of the results of the sample measurements.
Estimated Loss
≈ 3%
Potential Induced Degradation
PID causes power losses close to 15% on system level. The degradation is in a fairly advanced stage.
Estimated Loss
≈ 15%
Total Estimated Energy Loss
≈ 18.8%

Proposed Solutions

A weather station, or at least an irradiation sensor on the module plane, shall be installed so that the performance of the system can be properly determined.
The adjustment of the tilt angle towards the optimal angle could result in ca. 2.8% increase in the effective irradiation on the module plane.
An anti-PID measure, such as anti-PID box, shall be implemented in order to stop or reverse the degradation. PV modules showing power drops above the warranty conditions shall be replaced. If the replacement is not possible, the modules shall be regrouped in power classes within the same string and assigned to individual MPPT.
The modules with the same tilt and azimuth shall be grouped in strings with the same MPPT.