In recent years, the occurrence of severe weather events in Europe is becoming more and more frequent, with the most prevalent being floods and hail. PV installations could not remain unaffected by these natural disasters.

On a daily basis, we see images of damage to facilities submerged in mud and PV modules destroyed by hail.

What is, however, the extent of the damage to the PV modules in a facility affected by flooding or hail? Are the PV modules suitable and safe for reuse or do they need to be replaced? Will there be a loss of power and output? The investor is has to to find answers to all these questions.

To begin with, we look at the possible damage found in PV modules that have been affected by floods or hail.

Damage due to flooding

In cases of flooding, damage to PV modules can be a result of:

• The flow of water, along with suspended solids, between the PV modules, resulting in the creation of microcracks in the PV cells
• Water ingress into the junction boxes of the panels, resulting in defects in internal connections and diodes
• Water ingress into the panel connectors, resulting in corrosion
• Frames being burdened with polluting agents (lubricants, fuels, etc.) resulting in corrosion, reduction of insulation resistance, etc.

Amongst the above possibilities, the most frequently occurring damage is the creation of microcracks in the cells due to the impact of suspended materials carried at high speed. The extent of this damage depends mainly on the speed of water flow and the size of the debris.

Damage due to hail

In cases of hail, the most common damage includes:

• Glass breakage on PV modules; in this case we should consider recycling them since the only solution is replacement
• Creation of microcracks in PV cells, invisible to the naked eye, which can be confirmed with an EL test

Confirming the existence, extent and severity of damage (microcracks) in PV modules that have been affected by flooding or hail can be carried out exclusively by electroluminescence testing (EL test), which is essentially an X-ray of the PV cells.

The electroluminescence test can diagnose microcracks that are not visible during visual inspection and cannot be proven in any other way.

With over ten years of experience in PV module testing, Kmetrics and its specialised staff provides certified testing services using the electroluminescence (EL test) method, both in Greece and in the rest of Europe, with the Mobile PV Testcenter and the high-resolution portable device Mobile EL 01 .