Dr Jacqui Crozier McCleland; Prof Ernest Van Dyk with the PVinsight mobile testing lab at Nelson Mandela University; Electroluminescence imaging of PV modules on-site
Testing photovoltaic (PV) modules or solar panels for solar plants has become more critical than ever with the huge growth in solar PV plants in South Africa’s commercial and industrial space.
Commercial and industrial level solar plants are a major financial investment and solar modules should be independently tested for pre-installation and on-site once installed to make sure they meet the manufacturer’s specifications.
PVinsight (Pty) Ltd is the only accredited mobile laboratory testing service in South Africa, offering in-lab and on-site PV testing services.
This month the company is celebrating ten years of operation in parallel with the growth of the PV industry.
The company is run by a team of physicists and researchers with over 30 years of research and experience in PV systems. It was spun out of the Photovoltaics Research Group (PVRG) in the Department of Physics at Nelson Mandela University.
“We test modules at all levels, from the utility scale that feeds into the electricity grid to plants that power industries, companies and communities,” says the CEO and co-founder of PVinsight, professor of physics, Ernest van Dyk.
“Our testing is done according to the International Electrotechnical Commission (IEC) standards and we are accredited as a testing laboratory with the South African National Accreditation System (SANAS).”
The independent laboratory specialises in verifying claimed module performance.
This is essential as defects can creep into modules at the manufacturer level, with the cell quality and the cell interconnections as well as the fabrication of the entire module.
Damage, such as cracks, can happen during the manufacturing process or when they are transported, handled or installed.
The modules also need to be tested during the warranty period and over time to see if they are performing as per the manufacturer specifications. Many operations are finding their PV plants have underperforming and failing modules.
Companies, insurers and investors have not by and large been aware of how essential it is to include independent testing in their contracts, but this is changing as the industry matures.
“If the manufacturer knows their modules will be tested, they have to make sure the quality is according to specification across the entire range of modules,” says Dr Jacqui Crozier McCleland who has a PhD in physics, and is PVinsight’s Operations manager.
PVinsight has two mobile units which operate countrywide with teams able to test all module sizes and power ratings. The tests can also be used in warranty claims.
When clients are armed with an accredited module report, it greatly empowers them in terms of recourse with the manufacturer or project developer should any problems be detected.
PVinsight’s latest method of testing to see if any of the modules in large PV plants have defects or damage is Electroluminescence (EL) imaging.
It is a huge game-changer for business and industry in South Africa, achieving the best testing rate in South Africa.
“Large PV plants have hundreds of thousands of modules,” explains Dr Crozier McCleland.
“For example, a large 70MW PV plant would have about 300 000 modules, of which 300 – 500 modules need to be independently tested to give the purchaser greater peace of mind that the PV modules are without defects or that they meet the manufacturers specifications in terms of quality, power output and lifespan.”
With EL imaging they can test 500 to 800 modules per night to see if they are damaged in any way. Dr Crozier McCleland says “We test the modules at night so that the EL camera can detect the emitted EL light without interference from other light sources. Testing at night also means the PV plant does not lose production during the day.”
To further advance testing in South Africa, the company has formed a strategic partnership with the German company AePVI (Aerial PV Inspection GmbH).
Andreas Fladung, co-founder of AePVI says: “Today, innovative high-volume EL measurements in the field enable clear and meaningful quality analyses at cell level with regard to production, transport and installation loads, ageing processes and environmental events. No other measurement method currently offers this depth of analysis.”
The light emitted by the modules during the EL imaging test is not in the visible spectrum and it picks up defects that are invisible to the naked eye, such as broken cells.
“With broken cells (which show up in the image as dark areas), the module won’t produce as much power as if they were all uniform,” says Dr Crozier McCleland. “There are also sometimes manufacturing defects that decrease the module’s performance.”
As important as testing the new modules coming onto the market is to test the original utility-scale PV plants that are now 10 years old.
Performance issues and degradation can occur over time so it is important to check these plants so that good decisions can be made about how to improve their performance or replace and update modules.
For more information about PV testing, or to register for the event, visit www.pvinsight.co.za