An international research team coordinated by the American Institute of Physics claims to have successfully applied the clear-sky methodology developed by the U.S. Department of Energy’s National Renewable Energy Laboratory (NREL), to obtain a more accurate assessment of solar module performance.
According to findings presented in the paper Reliable long-term performance assessment of commercial photovoltaic modules tested under field conditions over 5 years, published in the Journal of Renewable and Sustainable Energy, the open-source, clear-sky methodology – which helps determine solar irradiance at a location in ideal, clear-sky conditions – is a very efficient tool to evaluate the aging of PV technology under field conditions when combined with real-world data. Such extra information is commonly provided by pyranometers, a type of actinometer used for measuring solar irradiance on a planar surface. Pyranometers, said the Institute of Physics team, are often a source of errors and malfunctions but integration with the clear-sky methodology could help reduce inaccuracy.
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