TUV Rheinland has developed a new accelerated environmental testing methodology to simulate long-term operational conditions that solar photovoltaic modules could experience throughout their lifetime, more accurately approximating real outdoor module behavior and power output degradation characteristics in a laboratory environment.
The company's “long-term sequential testing” exceeds the requirements of the IEC 61215 standard with an approximately nine-month-long test sequence that evaluates the degradation of solar modules affected by multiple external variables. The sequence consists of four major subcomponent tests: damp heat, thermal cycling, humidity freezing, and bypass diode.
An even-more challenging protocol, known as “PLUS”, includes optional plug-in tests for hotspots, hail, and mechanical load tests.
Due to the harshness of the sequence, only a limited number of products will be able to pass these tests, as a single test module is put through this sequence, and the degradation in power generated is measured after each stage, the company explained.
“Some module manufacturers have already shown interest in our new test method,” said Stefan Kiehn, head of TUV Rheinland's testing facilities in Japan. “Now that the market is promising up to 25 years of life for a PV module, end-users are asking for more evidence to give them confidence in a solar investment.”
“TUV Rheinland's Long-term sequential testing does not guarantee that the product will be as perfect in 25 years as when it was purchased, but it can help manufacturers to better understand how their modules may behave after being in use for a long time,” he continued. “Until now this was only possible through real outdoor lifetime testing.”
The first customer for the new service, Kyocera, said it has already completed major milestones in the tests. The PV manufacturer said that its standard 210W module has passed two of the four major subcomponent tests (damp heat, thermal cycling) of the new TUV protocols, and expects to complete the other two (humidity freeze, bypass diode) by December.