Site II.7

Health
COD
2017
Nominal Capacity
55.8 kWp
Yield since COD
896 kWh/kWp
Possible Gain
6% to 10%
CAPEX, OPEX
0.4 ₹/Wp, 0.5 ₹/Wp/a

Abstract

The PV plant shows moderate levels of soiling caused by dust, bird droppings and foliage. The system design disregarded near shading losses. DC cables lay unprotected on the roof. Significant mechanical damages at the module level were detected. It is recommended to (i) increase the cleaning cycles, (ii) trimming of trees surrounding the system if allowed by the authorities, (iii) drainage maintenance and (iv) restringing of the modules according to the shading situation. The estimated production boost expected by the retrofitting actions lies between 6% and 10%.

Image gallery

Main Findings

The access to the roof is difficult. This could have caused module damages during handling and installation. The electroluminescense images show a considerable number of cracks, leading to inactive cell areas.
The drains are blocked and the cables are exposed to UV radiation. Discoloring of the cables was observed. The cables are not fixed and laid properly. They were seen messily laying on the roof, vulnerable to radiation and mechanical damages. Pipes and tubes conveying cables are not sealed, and they are not robust.
There is no weather station, and hence no PR monitoring.
Near shading is caused by nearby trees and some of the objects on the roof.

Impact on Performance

Near Shading

Near shading losses are estimated to be close to 3% on the system level, based on the simulation.

Estimated Loss
≈ 3%
Cell Cracks

Performance losses based on the severity of cell cracks found on site are estimated to be 5% at the system level.

Estimated Loss
≈ 5%
Soiling

Soiling losses were determined to be 3% on average, based on the measurements on site.

Estimated Loss
≈ 3%
Total Estimated Energy Loss
≈ 11%

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 trees surrounding the system shall be trimmed if allowed.
For the modules shaded by the objects on the roof, a restringing shall be conducted in the following way: modules with similar shading conditions shall be installed in the same string or at least assigned to one MPPT. Otherwise, the objects shall be relocated.
A manual cleaning of the modules shall be scheduled.
The cables shall be kept away from possible mechanical damages.