Behavior of bifacial and monofacial photovoltaic modules under partial shading scenarios

Abstract

The current industrial scenario highlights the increased attention being awarded to bifacial photovoltaics (PV) technology due to its property of flux absorption from the rear side. But akin to monofacial modules, bifacial modules are also subjected to shading scenarios due to non-uniform illumination.A case study for comparative analysis on performance of bifacial and monofacial PV system is presented for Jaipur, India, which falls in the composite zone of Indian climate. An attempt has been made to quantify the performance of bifacial PV module under various shading scenarios and compared with monofacial module under similar condition. The work is done using a threephase approach, wherein initially the performance is studied at a module level and simulations performed to generate voltage profiles of individual cells under shade. This is followed by determining optimum inter-row spacing through experiment and RADIANCE simulations in an attempt to mitigate unwanted shade due to adjacent rows in an array. Finally, a dynamic approach to reconfigure the array under shade, combining electrical and physical reconfiguration methods to mitigate shading is studied. Based on the results of the study, bifacial technology always emerges as the superior in terms of power output over conventional monofacial technology for a wide range of partial shading scenarios. Combined physical and electrical array reconfiguration for a 3 Â 3 array shows fill factor reduction can be limited to 18.9% compared to non-uniform shade reduction of over 40%.