Irradiance Transposition Models from Horizontal to Tilted Plane for Photovoltaic Power Calculation

The accurate estimation of solar irradiance on inclined surfaces is essential for the assessment of Photovoltaic (PV) system performance and energy yield prediction. This paper presents a comparative analysis between three transposition models for converting solar irradiance from the horizontal plane to tilted surfaces. Additionally, two PV power models are analysed, starting from transposed irradiance while accounting for loss factors such as low-irradiance and thermal losses, degradation, and conversion losses. The performance of the models is investigated using measurements from a meteorological station, and from actual PV plants. Error metrics are evaluated to quantify deviations between modelled and measured profiles.