What Reliability Tests do Panels Undergo?
I've been poring over manufacturing datasheets and reliability documents for hours and feel like I'm getting nowhere. What are the main criteria I should be looking for to ensure my modules will last the test of time?
PV modules in the field are exposed to a host of trying environmental conditions. Thermal cycling, humidity, UV exposure, corrosion, hail, wind, and snow all come to mind. For a solar installation to be successful, it is critical that PV modules perform to expectations over the entire 25+ year service lifetime. To protect stakeholders in the event of failure, most manufacturers offer 10+ year product warranties and 20-30 year power warranties. Some take the extra step of offering warranty re-insurance.
All PV modules used in the United States must receive UL 1703 safety and IEC 61215 performance certifications. These certifications merely qualify a module design and do not address long-term performance. To ensure long-term reliability, module designs should be tested well-beyond those benchmarks, and then manufacturing processes are adjusted to repeat those designs within acceptable tolerances. This should be a continuous, iterative process, where real sample batches are chosen at random from manufacturing lines and markets.
Many third-party qualification firms have begun such comparative testing programs. For example, Fraunhofer ISE and CSE published the first wave of results from its Photovoltaic Module Durability Initiative this past June. Since short-term tests are used to assess long-term reliability, the programs are accelerated to expose modules to a series or combination of extreme conditions. A module could undergo damp heat and UV exposure together.