A performance modeling and optimal orientation of bifacial PV modules: A case study from Saudi Arabia

This study develops an integrated bifacial photovoltaic (PV) performance and orientation-optimization framework to determine the optimal fixed tilt and azimuth angles that maximize annual energy yield under desert climate conditions. The methodology combines established solar geometry formulations, advanced diffuse irradiance modeling, and bifacial performance considerations, and is applied using Tier-I hourly ground-measured solar irradiation and air temperature data (±2% accuracy) for 18 cities across Saudi Arabia. Unlike conventional latitude-based tilt rules, the proposed framework systematically identifies optimal bifacial orientations, revealing that the optimal tilt angle is typically 4°–30° higher than site latitude, depending on location and climatic conditions. Monthly analysis for Riyadh shows that bifacial modules maintain higher summer tilt angles than monofacial systems, enhancing rear-side contribution. The rear side contributes approximately 8–12% of total energy yield, with higher contributions during spring and autumn due to increased ground-reflected irradiance. A nationwide comparison indicates a relatively narrow bifacial gain range (9.3–11.5%), with higher gains observed in regions characterized by greater diffuse irradiance. The results are validated through consistency with previous monofacial PV orientation optimization studies and independent GIS-based suitability analyses. Overall, the proposed framework provides a transparent and robust decision-support tool for early-stage bifacial PV planning and comparative assessment in arid and desert environments.