Estimating bifacial loss factors for annual utility scale simulations

Detailed ray tracing simulations of typical bifacial PV systems are used to evaluate appropriate annual loss factors for use in software using 2D view factor models. Structure shading for 1MIP and 2MIP are found to be 7.8% and 6.5%, respectively; backside mismatch parameters for 1MIP and 2MIP are estimated as 2.4% and 2.5%, respectively. The 1MIP results are validated by comparing PVsyst predictions using the parameters to an experimental setup, finding that the energy produced by the two bifacial 1MIP arrays over the test period could be predicted with better than 0.3% accuracy.