Researchers at the University of New South Wales found that east-west ground-mounted PV systems can experience up to 40% lower rates of certain degradation mechanisms than single-axis trackers. Their simulations showed that lower operating temperatures and reduced UV exposure could improve module reliability, particularly in remote installations.
A research team from the University of New South Wales (UNSW) in Australia has compared the performance of east-west ground-mounted PV systems with that of conventional single-axis trackers (SATs), finding that east-west installations can experience up to 40% lower rates of certain degradation mechanisms.
“We investigated how improved thermal modelling can provide more accurate predictions of PV module operating temperatures and associated degradation rates, with a particular focus on the innovative Maverick east-west ground-mounted systems developed by Australian company 5B,” corresponding author Bram Hoex told pv magazine. “Heat transfer coefficients for the east-west system were found to be comparable to those of single-axis trackers, indicating similar cooling characteristics. However, east-west systems operate at lower module temperatures due to reduced plane-of-array irradiance compared with tracking systems.”
The Maverick system is a prefabricated, relocatable ground-mounted PV solution designed for rapid deployment with minimal on-site labor. Each modular unit comprises up to 90 solar panels mounted on frames that unfold in a concertina configuration, with modules tilted at 10 degrees. The system features preconfigured electrical connections, a compact footprint, high power density, and minimal ground penetration requirements, making it suitable for sites with limited usable land or challenging terrain. Its modular design also allows deployment on previously underutilized land, such as mine waste rock dumps. In 2024, the technology was deployed in a 16.9 MW solar installation comprising 342 Maverick units at the Jundee gold mine in Western Australia.
The UNSW researchers explained that the system’s low tilt angles enable greater ground coverage and higher energy density per unit of land, while its prefabricated design simplifies installation. However, accurately predicting the performance of such systems requires improved thermal models, as module temperature affects both electricity output and long-term degradation. Conventional models often overlook factors such as wind direction, mounting configuration, thermal inertia, and radiative heat exchange with the sky. To address these limitations, the researchers developed a transient thermal model incorporating sky radiation and validated it against field measurements.
The team analyzed monitoring data collected between September 2022 and June 2023 at a 5B Maverick test site near Bungendore, New South Wales. The installation uses JinkoSolar PV modules rated at 315 W, with module temperatures monitored using thermocouples and local weather conditions recorded by a nearby weather station. The researchers collected irradiance, ambient temperature, wind speed, wind direction, and electrical output data to develop and validate five thermal models of increasing complexity. These incorporated wind-dependent heat transfer, radiative exchange with the sky, and transient temperature effects. The models were calibrated against field measurements, with ERA5 climate data used to improve estimates of longwave radiation.
The researchers then simulated the thermal performance of Maverick and single-axis tracking systems at two Australian locations: Bannerton in Victoria and Clare in Queensland. The simulations used bifacial Longi modules and SMA inverters, with different DC-to-AC ratios for the two mounting configurations. The team assessed two degradation mechanisms: thermal degradation caused by temperature fluctuations and photodegradation associated with ultraviolet exposure, temperature, and humidity. It also mapped expected degradation rates across Australia to investigate the influence of regional climatic conditions.
The analysis showed that incorporating radiative heat exchange with the sky and transient temperature effects significantly improved simulation accuracy, particularly at night and during rapid temperature fluctuations. The improved model was validated against measurements from multiple modules at the Bungendore test site, demonstrating consistent performance across different orientations.
The simulations indicated that Maverick modules generally operate at lower temperatures because their fixed orientation results in lower plane-of-array irradiance. Single-axis trackers receive more sunlight and generate higher energy yields per module, but their greater irradiance exposure also increases operating temperatures.
The researchers found that higher operating temperatures, combined with increased ultraviolet exposure, resulted in greater thermal degradation and photodegradation in tracking systems. Both degradation mechanisms were most pronounced during summer, when temperatures and irradiance levels peaked. Simulations across Australia indicated that Maverick systems were less susceptible to both mechanisms, with particularly pronounced differences in thermal degradation in southern and southwestern regions.
The researchers also noted that inverter clipping and power curtailment could accelerate degradation by increasing module temperatures. They concluded that the lower degradation rates associated with fixed east-west mounting systems could make them particularly attractive for remote installations, where maintenance and replacement costs are higher.
“Our work demonstrates that PV mounting configuration directly influences module reliability, not just energy yield and installation costs,” Hoex explained. “It also highlights the importance of accurately modelling module temperature when predicting long-term degradation and lifetime energy production.”
“Our findings also provide a framework for integrating temperature-dependent degradation into PV system simulations, moving beyond conventional fixed annual degradation assumptions,” he added. “Moreover, they suggest that low-tilt east-west configurations could offer additional benefits through reduced degradation, complementing their advantages in land utilisation and deployment costs.”
The findings are presented in the study “Accurate Modeling of Module Temperature for Ground-Mounted PV and Its Impact on Degradation,” published in the IEEE Journal of Photovoltaics.
In previous research, UNSW scientists found that single-axis tracking PV systems experience higher ultraviolet-induced degradation than fixed-tilt installations. The researchers developed a global UV irradiance model showing that trackers can receive up to 1.5 times more UV radiation than fixed-tilt systems in high-irradiance regions, resulting in degradation rates nearly twice as high. The study also highlighted the influence of temperature, humidity, and atmospheric conditions on module degradation, particularly in tropical and desert environments.
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