Interleaving as a best practice for outdoor comparative performance testing of photovoltaic panel technologies

Researchers often want to compare two or more photovoltaic panel technologies under real-world conditions to obtain a comprehensive understanding of module performance. A well-controlled study typically necessitates installing a string of modules for each technology. However, real-world effects of prevailing wind direction, site obstructions, and array edge effects can introduce uncontrolled variation in site microclimates thereby skewing the results. In this paper, field data is presented showing that the magnitude of error resulting from these uncontrolled variations can be on the order of 1%. A method is presented and validated, which largely eliminates the effect of microclimates by interleaving module types under study. A guideline for complex topologies is introduced.