Advancing solar farm diagnostics with daylight photoluminescence imaging

In 2025, UNSW’s Daylight Photoluminescence (DPL) Imaging Group, led by Professor Thorsten Trupke and Dr Oliver Kunz, with ACAP support, continued to drive their drone-based imaging solutions which have great potential to transform how solar farms are assessed, monitored and maintained. 

Their pioneering DPL technology allows operators to ‘see’ hidden defects in solar panels in broad daylight, providing rapid, high-resolution diagnostics – that were previously only possible under controlled laboratory conditions or via measurements at nighttime.

The ACAP supported team are developing drone-based daylight photoluminenscence (DPL) imaging of solar farms for high resolution diagnostics, for routine, low-cost, aerial inspection of large solar sites.

Demonstrating automated drone–based DPL field inspection

Major progress has been made towards automated, field-deployable inspection systems. The team delivered successful demonstrations at Australian utility scale solar farms, in conjunction with industry partner Gentari Solar Australia.

Substantial progress was demonstrated towards drone-based DPL imaging that combines automated pre-programmed flight paths with synchronised inverter switching. This is a significant step towards routine, low-cost, aerial inspection of large solar sites. 

The group’s drone inspection capabilities were demonstrated internationally during an on-site trial with US industry partner GAF Energy at its California headquarters, as well as in a customised residential setting.

Advancing DPL image analytics and processing

DPL image of a solar module with partial current extraction, featuring a cell with a distinctive series resistance defect. The UNSW DPL team has developed a new method to quantify power losses caused by series resistance directly from DPL images.

The group also welcomed Dr Ryan Hall, who is driving advances in real-time image processing, including distortion correction and automated image registration, bringing the technology closer to commercial-grade performance. 

Among the year’s scientific milestones was the completion of a new method to quantify power losses caused by series resistance directly from DPL images – published in Progress in Photovoltaics[1], and securing an Australian Economic Accelerator (AEA) grant to accelerate the development of image analytics. 

Series resistance problems are common in solar panels and occur when ageing contacts and cell interconnections make it harder for electric currents to flow. This reduces the panel’s power output and often signals deeper wear and tear. Spotting these issues early helps explain and quantify performance losses.

Commercial DPL inspection services launched

Lab 360 Solar, a UNSW spin-out developing DPL imaging systems and commercial inspection services (on-site inspections, quality assessments) was established in 2024, and began active operations in 2025, securing ARENA and NSW Government support and moving into new premises in Surry Hills.

ACAP’s sustained backing has been central to this progress, supporting staff time, early equipment purchases and the stable environment needed to progress DPL imaging from a laboratory idea to a field-proven, globally recognised innovation. With new ACAP project proposals now under consideration, the team is poised to further expand Australia’s leadership in advanced solar diagnostics and performance assessment.

Reference

^[1] H. Gottlieb, O. Kunz, J. Weber, Z. Ouyang, and T. Trupke, “ Power Losses From Series Resistances—Analysed Using Daylight Photoluminescence Imaging,” Progress in Photovoltaics: Research and Applications 33, no. 11 (2025): 1247–1259, https://doi.org/10.1002/pip.70022.

PL imaging specialist Juergen Weber, testing the DPL-equipped drone over a solar farm in Victoria.