Bifacial Performance Modeling in Large Arrays

Bifacial modules are being deployed at large PV systems, because of the potential to increase energy output, but their performance is still uncertain, increasing financial risk. To address the opportunity that bifacial modules present, we have developed a bifacial performance model and integrated it into a full PV system model to estimate the backside irradiance, combine it with the front side, and predict the total output power. To understand the effect of bifacial on performance, the NIST test array was simulated with bifacial modules and compared to an equivalent monofacial system while varying tilt from 20° to 40°. A bifacial gain of 10% was observed which increased with increasing tilt angle. The maximum yield occurred at 30° for the bifacial system, but at 25° for the monofacial system, demonstrating the advantage of modeling bifacial systems to optimize their performance.