The ability of short term performance tests to reproduce the results of a one-year adjusted energy test for non-concentrating PV systems

A variety of test methodologies are commonly used to assess if a photovoltaic (“PV”) system is able to perform in-line with expectations generated by a computer simulation. Four commonly used methodologies include: the PVUSA rating as implemented in ASTM E2848 and E2939 (“ASTM”), a Performance Ratio Test (“PR”), the Power Performance Index (“PPI”) and the Adjusted Energy Test (“AET”). This paper compares the results of a one year AET to short term ASTM, PR, PPI, and AET test results in an attempt to determine which test can best reproduce the results of a one-year AET. Test durations of 3, 7, 15, and 30 days were evaluated to examine the effect of test duration on the residual between the short term test result and the long term AET test result. Seasonality was also examined. This study was not able to identify a single test methodology which consistently outperformed the others, nor was this study able to determine the optimum test duration.