Most photovoltaic module manufacturers guarantee 90% efficiency for 10 years, and 80% for 25 years. However, as a panel ages, gradual degradation occurs and one of the most significant causes is the module hotspot. This may occur due to high resistive joints, panel cracks, or a variety of other reasons. Abnormal weather conditions (lightning, storms), panel cell overheating, and other component failures can also lead to hotspots within a PV module.
An internal study concluded that hotspots can lead to a 16% loss of efficiency in a single module, and that they are the primary threat to PV modules. If left untreated or treated incorrectly, these hotspots can compromise panel performance until fixed or, in more severe cases, cause long-lasting damage requiring costly repairs. We’ve detailed the extent of power loss caused by hotspots in our portfolio case study on Aerial Thermography.
Asset owners of utility-scale Solar PV projects can curb power loss issues by conducting frequent inspections for such hotspots and taking immediate remedial action. Since these hotspots are not visible to the naked eye, maintenance personnel use infrared thermography techniques to capture temperature distribution images of PV modules and identify the defects.
What is Infrared Thermography?
All objects emit invisible, infrared energy. Asset owners can employ LWIR thermal imaging cameras to accurately capture detailed temperature information of each cell in a solar module through infrared thermography.
Importance of Aerial Thermography
Aerial thermography is a real game-changer in solar inspection. Use of drone technology for solar inspection eliminates manual, labour-intensive methods. The thermal data combined with visual imagery captured during aerial thermal inspection provides valuable and actionable information to project stakeholders. This method also eliminates the need to conduct on-site field walks to identify performance issues related to soiling or shading.
Field technicians no longer require exploratory handheld imaging of modules because every module is documented in a radiometric thermal image embedded with precise temperature data. In turn, O&M teams can spend less time in discovery mode trying to troubleshoot the cause of issues detected in system monitoring and spend it resolving them instead.
Major Defects Identified by Infrared Aerial Thermography Inspections
Naked-eye inspections can only identify dust and other physical defects within the modules. Through aerial thermography inspections, the Datasee.AI platform can assist O&M teams in identifying the following categories of hotspots within PV modules:
- Bypass Diode Failure
- Open Circuit
- Short Circuit
- Cell Failure
- Module Failure
- Tabel Failure
- PID
- Delamination
- Broken Glass
Conclusion
Aerial thermography is a cost-effective, fast, and accurate solar PV inspection method. Through this technique, O&M teams can carry out sub-module level analytics on 100% of the modules and avail detailed classifications of every identified anomaly and their respective power loss information enabling solar operations teams to make data-driven decisions to improve site productivity.