Standards relating to the performance of photovoltaic modules have historically focused on initial qualification testing and not issues of durability and functional service life. Subcommittee E44.09 on Photovoltaic Electric Power Conversion is now working on a proposed new standard that will cover these long-term issues: WK25362, Practice for Photovoltaic Module Reliability Assessment. The subcommittee is under the jurisdiction of Committee E44 on Solar, Geothermal and Other Alternative Energy Sources.
“While a module may meet the initial qualification requirements, this does not provide sufficient information to indicate that the same module will function reliably in the long-term,” says David Burns, an E44 member and senior specialist, 3M Weathering Resource Center. “The intent of WK25362 is to recommend procedures for conducting accelerated life testing of photovoltaic modules to provide a common ground for manufacturers and users to assess durability and estimate functional service life.”
The results of test protocols described in WK25362 will help designers and manufacturers identify and quantify the important failure mechanisms that can limit the service life of PV modules as well as provide methods to evaluate the rate of performance degradation.
“When approved, the proposed standard should serve as a technical framework for evaluating improvements to increase the long-term performance of PV modules,” says Burns. “The driving issue behind WK25362 is how to evaluate whether a PV module will function for an acceptable amount of time. To that end, it could also potentially be used to corroborate claims of warrantable lifetime.”
In addition, WK25362 will educate users — including distributors, installers and residential owners — on PV property-performance-cost relationships such as electrical output versus environmental variables, corrective and preventative maintenance and design factors that influence operational reliability.
Among the potential users of WK25362 are PV module and component designers and manufacturers, testing and certification laboratories, government laboratories, commercial PV users and solar energy consumer advocate groups.
All interested parties are invited to take part in the ongoing development of WK25362 and in other standardization activities of Committee E44. Areas of expertise that would be useful to the committee’s work include reliability monitoring, service life prediction methodology, performance measuring, module construction, materials and associated electrical components.
Technical Information: David Burns, 3M Weathering Resource Center, 3M Co., Maplewood, Minn.
ASTM Staff: Christine DeJong