Site II.2

Health
COD
2018
Nominal Capacity
71.5 kWp
Yield since COD
696 kWh/kWp
Possible Gain
27% to 33%
CAPEX, OPEX
1.2 ₹/Wp, 0.4 ₹/Wp/a

Abstract

The PV plant is affected by significant soiling caused by concrete splattered on the modules. 10% of the modules were found with broken glass. PID was found to be in a fairly advanced stage and several DC cables showed evidence of monkey bites. The new buildings erected on the west part of the system induce a significant amount of shading during the afternoon. It is recommended to: (i) replace every broken module, (ii) increase the cleaning cycles, (iii) rearrange the strings based on shading categories and (iv) implement anti-PID solutions. The estimated production boost expected by the retrofitting actions lies between 26% and 32%.

Image gallery

Main Findings

The module connectors show damages since they were opened with improper tools. A loose connection of the module connectors has caused burning.
A significant number of modules show mechanical damages on the front glass.
Some fuses in the combiner boxes have burned.
Cables damaged by monkey bites were observed.
There is no weather station, and hence no PR monitoring.
The PV plant is partly surrounded by buildings which cast shadows onto the modules.
PID presence was detected via IR and EL inspection.

Impact on Performance

Soiling

Some parts of the PV plant are heavily soiled (soiling loss determination was not possible due to bad weather). The loss is estimated to be >10% based on past experiences.

Estimated Loss
≈ 10%
Cell Cracks

The significant number of broken modules could lead to a performance loss of at least 7% at the system level.

Estimated Loss
≈ 7%
Near Shading

Based on the simulation, the shading losses due to the surrounding buildings is ca. 4.8%.

Estimated Loss
≈ 4.8%
Potential Induced Degradation

PID was found to be in a fairly advanced stage. This could result in a performance loss of as high as 10% at the system level, based on PI Berlin experiences (on-site measurement was not possible).

Estimated Loss
≈ 10%
Total Estimated Energy Loss
≈ 31.8%

Proposed Solutions

The broken modules shall be replaced with new modules.
The cleaning cycles shall be increased based on the results of a soiling study that adjusts the cleaning needs to each season.
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.
A restringing of the modules from the shaded areas shall be conducted in the following way: modules with similar shading conditions shall be installed in the same string or at least assigned to individual MPPTs.
Anti-PID measures 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 MPPTs.
Covering the ground with white gravel or white paint increases the albedo factor to 0.5, leading to performance boost of approximately 1%.