Incidence Angle Effect: Results of an Interlaboratory Comparison of Measurements on Commercial-Size Modules

The incident angle effect causes a decrease in the photogenerated current of PV modules when they are subject to incident irradiance at wide angles: its relevance should be quantified for accurate energy yield purposes and has recently gained significance due to the raising interest in innovative vertically integrated PV applications (e.g. in urban structures, in agrivoltaics, and in vehicles). The international standard IEC 61853-2 presents both an outdoor and an indoor measurement method: however, the indoor measurement method for commercial-size modules is often impractical due to irradiance uniformity limitations on the volume spanned by the tested module upon rotation. In recent years, new solutions have been proposed to overcome these limitations and allow a wider adoption of this standard, but method validations and interlaboratory comparisons have been conducted so far only at small-area samples and a real validation on commercial-size modules is still to be performed: in this work we aim at fulfilling this goal, reporting the results of an interlaboratory comparison conducted within the international Project Team that is currently working at the new edition of IEC 61853-2. Result shows remarkable agreement between different measurement methods, thus validating more options for the evaluation of this important effect.