Scientists in Qatar have outlined a new approach to optimize residential bifacial PV systems by combining south-facing and vertically mounted east-facing configurations. The novel methodology reportedly results in a 21.6% increase in a system’s net present value.

A research team led by scientists from Qatar’s University of Doha for Science and Technology investigated the optimization of bifacial PV panels in a residential setting, focusing on maximizing economic benefits based on load profiles.

“This research introduces an innovative approach to optimizing bifacial PV panels in residential settings by combining south-facing and vertically mounted east-facing configurations,” said the corresponding author, Muhammad Zubair, to pv magazine. 

Using the System Advisory Model (SAM) software, the research team first compared mono-facial and bifacial systems, later optimizing the latter under different load regimes.

“By comparing zero-export grid-connected and net metering configurations, this study provides actionable insights into maximizing the net present value (NPV) of PV investments under real-time buyback conditions,” the scientists said. “Unlike previous studies that primarily focus on south-facing configurations, this research introduces a hybrid bifacial PV system combining south-facing and east-west-facing orientations. This innovative approach optimizes azimuth and tilt angles based on real residential load profiles, enabling three distinct energy generation peaks throughout the day.”

The PV systems were simulated to be set on a rooftop in Islamabad, Pakistan’s capital city. The city receives 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. The load of residential customers is an average value of 70 houses in the city. Local electricity costs and the cost of different system components were based on several databases. In all cases, the capacity of the system was 5 kW.

The simulation showed that bifacial PV panels produce 10% more energy than a monofacial PV panel placed in the south-facing configuration. Furthermore, it showed the bifacial panels achieved a 13.6% higher net present value (NPV), a 4.5% lower levelized cost of energy (LCOE), and a 5% lower payback period.

Analyzing the height of a vertical bifacial system, with the range being 0 m to 2.5 m, the academics found that it should be placed at least 2 m above the surface. They also noted that a bifacial PV system installed at a height of 2m has a 7.6 times higher NPV than bifacial PV panels placed directly on the rooftop.

In the case of a zero-export grid-tied system, which is common in Pakistan, the optimized bifacial system 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 customer’s load profile. If optimizing the system to face the east, the optimal results required placing the panels vertically, which resulted in a 9.7% higher NPV of $2,787. However, the latter system produced 18.5% lower electrical energy over a year, compared to the south-facing one.

“These higher economic benefits while producing less energy in vertical east-faced bifacial PV systems are due to longer PV energy generation time compared to a south-faced PV panel with a single peak,” the researchers explained. “In the first year, the east-faced system could fully satisfy the load for 3,427h while the south-faced system was able to satisfy the load for 3,147h, which is 8.9% lower than an east-faced 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 showed that the time for which PV energy can be delivered to satisfy the load completely is 4,226h a year, which is 1,079h more than a south-faced bifacial PV system. The NPV of this system is 21.6% higher than a south-facing bifacial PV system of $3,091  at an LCOE of 1.87 cents USD/ kWh. The payback period is just 3.43 years,” they found.

Concluding their article, the researchers said that bifacial PV systems should be placed vertically east-faced for real-time buyback net metering regimes for power availability in two peaks when other PV plants are not producing at their peak. “The east-faced bifacial PV system provides 362 more h of power generation annually than the south-faced bifacial PV system,” they stated.

Their findings appeared in “Optimization of bifacial PV panels in a residential sector for maximum economic benefits based on load profile,” published in Energy Reports. Researchers from Qatar’s University of Doha for Science and Technology and Pakistan’s University of Lahore have conducted the study.