The figure shows the relative deviation between simulation data and measured data of the front irradiance Irr_front and the area-specific energy yield Y_b in the time frame of November 2019 to April 2020. Mode 1 and 2, which use VF for front side irradiance calculation, show the same results for Irr_front. The largest positive deviation is 19% in December and the largest negative difference is −16% in April. Mode 3, which uses RT, shows only positive deviations. The front irradiance deviations also translate over to the energy yield Y_b. Here mode 2, which uses only VF, calculates the highest deviations between simulation and measured data. The influence of RT for the calculation of the rear irradiance can be seen in the lower deviations of mode 1. The pure RT simulation mode 3 only produces positive deviations, which are highest in April with 16%.