Glossary
Photovoltaic system reliability and durability

Water vapor transmission rate (WVTR); WVTR (Water Vapor Transmission Rate)

WVTR, typically expressed in g·m^–2· ·j^–·1·, is a measure of water vapor transmission through a given material.

Light-induced degradation (LID); LID (Light-Induced Degradation)

Degradation mechanism related to changes in the metastability of cells and components in photovoltaic modules under the influence of light.

Light- and elevated-temperature-induced degradation (LeTID); LeTID (Light and elevated Temperature Induced Degradation)

A degradation mechanism that is still poorly understood, linked to the evolution of certain metastable states in silicon photovoltaic cells under the influence of light at high temperatures (generally above 50 °C).

Potential-induced degradation (PID); PID (Potential-induced degradation)

A failure mode associated...