| Work Detail |
Qatari scientists have outlined a new method for optimizing residential bifacial photovoltaic systems by combining vertically mounted south- and east-facing configurations. The new methodology results in a 21.6% increase in the systems net present value. A research team led by scientists at Doha University for Science and Technology in Qatar investigated the optimization of bifacial photovoltaic panels in a residential setting, focusing on maximizing economic benefits based on load profiles. “This research introduces an innovative approach to optimizing bifacial photovoltaic panels in residential environments by combining vertically mounted south-facing and east-facing configurations,” corresponding author Muhammad Zubair told pv magazine . Using the System Advisory Model (SAM) software, the research team first compared monofacial and bifacial systems, then optimized the latter under different loading regimes. “By comparing net metering and grid-connected configurations with zero exports, this study provides useful insights for maximizing the net present value (NPV) of PV investments under real-time buyback conditions,” the scientists say. “Unlike previous studies that focused primarily on south-facing configurations, this research introduces a hybrid bifacial PV system that combines south- and east-west orientations. This innovative approach optimizes azimuth and tilt angles based on actual residential load profiles, enabling three distinct power generation peaks throughout the day.” Photovoltaic systems were simulated on a rooftop in Islamabad, the capital of Pakistan. The city receives a global horizontal irradiance (GHI) of 5.24 kWh/m2/day with an average temperature of 21.3°C and an average wind speed of 1.7 m/s. Residential customer load is an average value of 70 homes in the city. Local electricity costs and the cost of individual system components were based on various databases. In all cases, the system capacity was 5 kW. The simulation showed that bifacial PV panels produced 10% more energy than a monofacial PV panel placed in a south-facing configuration. It also showed that bifacial panels achieved a 13.6% higher NPV, a 4.5% lower levelized cost of energy (LCOE), and a 5% shorter payback period. Analyzing the height of a vertical bifacial system, ranging from 0 m to 2.5 m, the researchers found that it should be placed at least 2 m above the surface. They also observed that a bifacial PV system installed at a height of 2 m has an NPV 7.6 times higher than that of bifacial PV panels placed directly on the roof. For a grid-connected zero-export system common in Pakistan, the bifacial system optimized for south-facing panels required a tilt angle of 30° and an azimuth angle of 190° to produce the highest NPV of $2,451 for the customers load profile. If the system was optimized for east-facing orientation, the optimal results required placing the panels vertically, which produced a 9.7% higher NPV of $2,787. However, the latter system produced 18.5% less electricity over the course of a year compared to the south-facing system. These greater economic benefits while producing less energy in east-facing vertical bifacial PV systems are due to the longer PV power generation time compared to a single-peak south-facing PV panel, the researchers explained. In the first year, the east-facing system was able to fully satisfy the load for 3,427 hours, while the south-facing system was able to satisfy the load for 3,147 hours, which is 8.9% less than an east-facing system. A final analysis included splitting the system into two: a 2.5 kW south-facing unit and a 2.5 kW east-facing unit. It was shown that the PV power supply time to fully satisfy the load is 4,226 hours per year, which is 1,079 hours longer than a south-facing bifacial PV system. The NPV of this system is 21.6% higher than a south-facing bifacial PV system of $3,091, with an LCOE of 1.87 cents/kWh. The payback period is only 3.43 years. In concluding their article, the researchers stated that bifacial PV systems should be placed vertically and face east for net metering with real-time buyback schemes to provide energy at two peak times when other PV plants are not producing at their peak. The east-facing bifacial PV system provides 362 hours more energy generation per year than the south-facing bifacial PV system, they stated. Their findings appear in “ Optimization of bifacial PV panels in a residential sector for maximum economic benefits based on load profile,” published in Energy Reports . Researchers from the Doha University of Science and Technology in Qatar and the University of Lahore in Pakistan conducted the study. |
