Spectral correction for photovoltaic module performance based on air mass and precipitable water

A model is proposed for characterizing the effects of spectrum on cadmium telluride and crystalline silicon photovoltaic (PV) modules. It is of simple functional form, allowing it to be easily implemented into standard PV simulation tools. The model corrects for changes in spectrum due to air mass and precipitable water content. The model has module-specific coefficients based on the module's quantum efficiency curve. For modules with similar quantum efficiency curves, the same coefficients can be used. Field performance data of operational PV arrays is used to validate the model. Results illustrate an improvement when compared to existing simple spectral correction methods and suggest that the proposed spectral correction should be included in PV prediction software.