Comparing the Accuracy of Horizon Shade Modelling Based on Digital Surface Models Versus Fisheye Sky Imaging

Fisheye sky imaging is a well established and accu-rate method for estimating shading in photovoltaic (PV) applications, however, it requires physical presence and measurements at the studied location. On the other hand, Digital Surface Models (DSM) can be used to estimate horizon shading remotely, and presents a more scalable method for evaluating potential PV installation site efficiently. Nowadays, high resolution DSM data is readily available in many countries, especially for urban environments. This has opened up new potential applications for more efficient shading estimation for aiding the deployment of PV in urban environments where horizon and nearby shading is significant. In this work, the accuracy of DSM-based methods to characterize horizon shading is assessed and compared to that obtained with fisheye imaging based methods. DSMs with different resolutions are studied and results show that high resolution DSMs are comparable. However, the accuracy of lower resolution DSMs will be highly influenced by the characteristics of the studied location.