The solar industry has grown and evolved hugely in recent years. When I started in the industry some 15 years ago, the largest photovoltaic project in the world was 10MW. Today, that would be considered quaint; as large scale power plants are installed by the multi-hundred MW. Growth has really taken off in the last couple of years with global installed capacity almost doubling between 2015 and 2017, and with PV capacity growing faster in 2016 than any other power source. And that trend will continue. The IEA predicts global PV capacity will hit 740GW by 2022 — and many industry observers think this is a conservative estimate.
Underpinning that growth is the continuous adoption of new technologies that improve efficiency and cut costs to make PV modules economic in more places and use cases. For example, innovations such as PERC (passive emitter and rear cell), half-cut and bifacial cells have all started to have a commercial impact on the market. And we can be sure that even more new innovations will emerge over the coming years.
These new technologies promise increased outputs and profitability for solar projects, but they also bring new risks. With little or no track record in the field, how can potential buyers be confident of the long-term durability of new technologies?
Growing reliability of PV modules
Module certification according to IEC standards give some indication of quality, but this set of standards does not address long-term reliability and durability. For purchasers’ peace of mind, the certifications need to be supplemented with dedicated reliability and performance testing carried out in a controlled laboratory environment. Today this is the only feasible way to verify the durability and reliability of modules in different field conditions over their expected lifetime.
DNV GL’s recently published PV Module Reliability Scorecard report shows a year-on-year improvement in the reliability of tested modules, which highlights the top performing manufacturers’ commitment to quality and durability.
This is a great achievement for the industry and shows that the top performing manufacturers are prioritising product quality. However, this improvement in reliability results doesn’t mean that PV module buyers can take module quality for granted when making purchasing decisions. Great care is still needed when choosing PV modules.
Fact-based decision making to reduce risks
For a start, reliability testing is voluntary. For all the value of reliability and performance testing, some manufacturers choose to test their modules only for safety — or not at all.
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Not testing modules fully can be a business risk for purchasers and manufacturers alike. As a buyer, an untested module offers no independent evidence that it will last long enough to deliver a return on investment for the entire product lifetime and/or warranty period.
For manufacturers, especially new and smaller ones, reliability testing can make it easier for them to enter markets where they currently have little brand recognition. Manufacturers who continually test their modules with a third party lab are able to demonstrate to buyers that they are committed to quality, which makes many RFP processes more successful for the manufacturer.
Twenty two per cent of manufacturers participating in DNV GL’s Scorecard study experienced at least one failure. Interestingly, the rate of failure was consistent no matter the size of the manufacturer or the geographic location of the factory.
This shows that prospective buyers cannot simply rely on brand reputation or size of the manufacturer.
In addition to manufacturer size, location or even Tier 1 status not being indicators of quality, the Scorecard highlights that different Bill of Materials (BOM) — or product structure — variants of the same module type can have very different test results. Not all manufacturers have all their BOM variants for any given module type tested for reliability and durability.
Thus, buyers need to obtain detailed BOM information and ensure the selected BOM has performed well in testing before considering a particular module type or BOM for their projects.
Tara Doyle is head of business development, solar laboratories, at DNV GL Energy.
The fourth edition of DNV GL’s report into PV module performance — the PV Module Reliability Scorecard — was published in May.