The impact of module technology, ground coverage ratio, and string configuration on the performance of bifacial PV systems on horizontal single-axis trackers in desert environments

Bifacial modules on horizontal single-axis tracker are becoming standard in utility-scale photovoltaic systems. However, tracker performance depends strongly on the module technology, system design, and the sites environmental conditions. This study evaluates the performance of two-in-portrait horizontal single-axis tracker systems, benchmarked against fixed-tilt systems in desert climatic conditions of the Middle East for twenty months. Three advanced commercial solar cell technologies - passivated emitter and rear cell, passivated emitter rear totally diffused, and silicon heterojunction were assessed under varying ground coverage ratios, string sizes, and module layouts. The tracker delivered an annual daily average gain of approximately 13.5%, with peak average daily gain of 36% during the summer. Tracker benefits were highly seasonal, with fixed-tilt system outperforming horizontal single-axis tracker by up to 7.2% in daily average energy yield during the winter. Annual bifacial gain in tracker ranged from 9.4% to 12.1%, increasing with diffuse irradiance and lower ground coverage ratio. Silicon heterojunction modules delivered the highest energy yield, particularly under high-temperature and high-irradiance conditions. String orientation effects were negligible, while smaller string sizes showed modest advantage. The findings provide valuable insights for technology selection and system design for energy yield optimization in high-irradiance desert regions.