Improved STC and energy yield performance of bifacial modules with white-grid rear reflectors

Abstract

We investigate the performance of bifacial white-grid solar modules using a white reflector on the module rear glass along the cell gaps. Considering the optical and long-term reliability properties of different colors, we determine the optimal geometry of the white reflector in ray tracing simulation. Based on these results we build test-modules and compare their performance under standard testing conditions as well as the annual energy yield with bifacial and monofacial references. White-grid modules outperform the bifacial references under single side indoor-measurements achieving a 1.6% higher module power output. Moreover, they improve the annual energy yield by 1.3% for a location in Hamelin. Comparing the performance gain for varying irradiance conditions indicates that white-grid modules are especially advantageous for locations with high fractions of direct sun light or the application on trackers.