How pixels can help reduce your solar investment risk

To most of us, solar panels all look the same. A glistering dark surface, teeming with energy potential. 

Researchers at the Council for Scientific & Industrial Research (CSIR) see a lot more, right up to the tiniest details. As with all energy sources, harvesting the most from solar technology is about understanding the details. And the smallest details often yield the most important results. 

Not all solar panels are equal. Evaluating PV quality goes beyond the electrical and environmental stress testing. The CSIR uses advanced imaging techniques and artificial intelligence (AI) to validate the quality of solar panels. 

Lawrence Pratt is the CSIR’s primary solar expert and leads the application of electroluminescence technology for PV quality assurance. Solar panels and pixels aren’t often imagined in the same sequence of thought, but using the latter to evaluate the former can yield huge savings. That's because by reducing the technical risks of installing substandard panels, the financial risk is also reduced.

Fundamental quality standards in the solar industry are robust, though the solar cells made from crystalline wafers found inside most solar panels are quite fragile. Encasing the sensitive solar cells in a robust exterior is crucial to longevity and peak performance over time. 

Engineers design PV panels to endure up to heavy mechanical loads, which can induce up to 150mm of deflection over a 2m surface area without breaking. In many cases, even extreme weather conditions and handling errors during transportation won’t crack a solar panel’s glass surface, but it’s below the outer glass surface layer where cell integrity can be compromised. 

CSIR researchers go deeper. Using digital cameras with their high band-pass filters installed, Pratt’s team capture electroluminescence images. These image files can reveal even the tiniest microfractures within a solar panel’s structure, which might only be one or two pixels wide. 

Infrared images have been a popular non-destructive testing technique, but electroluminescence imaging has superior accuracy for detecting cracks and other small defects. 

What is the benefit of identifying microcracks in a solar panel, invisible by most other methods of inspection? By applying AI and potent computing resources, CSIR testing teams can know a lot more about the fundamental quality profile of a panel, years in advance of potential degradation.

The difference between average and excellent PV components also leads to differences in power generation. Higher-quality components lead to systems with as much as 3% higher output. Compound the cost of that 3% power difference over the 25-year life cycle of most solar project installations, and the value of microcrack identification is obvious. 

Bringing electroluminescence imagery and testing software based on AI to the market enables the CSIR to empower solar customers and project engineers. The more panels are screened, the better the software becomes at recognising issues. 

Solar panels that might appear cosmetically perfect could have deep-structure microcracks. Identifying these prevents costly replacements a few years into a solar project’s generation trajectory. It also keeps the PV industry and supply chain disciplined regarding quality control. 

As more South African businesses, SOEs, homeowners and municipalities invest in PV projects, more intelligent testing can safeguard those investments and hedge against unnecessary expenses and future cost escalation. 

Hail damage is a real issue in SA, and though PV units might look undamaged, cricket ball-sized hail can smash glass on some PV modules while other modules in the same array look fine. However, the hail can create microcracks within a solar panel's cells that are undetectable to the naked eye. 

With the CSIR’s advanced testing methods, those hail-damaged microcracks can be discovered and managed before they cause significant generation downtime or a PV systems failure.

By testing and surveying for the slightest possible faults, the CSIR’s solar specialists help owners manage the life cycle risk of their PV assets instead of simply focusing on upfront costs. 

The solar energy future has much promise and a collection of unknowns. To scope projects for long life cycles, quality source data regarding the integrity of PV panels is crucial.

To schedule a consultation with the CSIR’s solar photovoltaic quality and reliability testing facility, email pvlab@csir.co.za. For more information, visit csir.co.za

This article was paid for by Council for Scientific &  Industrial Research.