Assessing the Accuracy of Publicly Available Spectral Irradiance Data From Nsrdb

Tuomiranta, Arttu, Drahi, Etienne

ISES Solar World Congress 2025 · Fortaleza, Brazil · 2025-11-03
Published by International Solar Energy Society (ISES)

Abstract

This study presents the first validation of the National Solar Radiation Database (NSRDB) spectral irradiance data outside North America, focusing on sites in France, Brazil, and the USA. Ground-based measurements were used to assess the accuracy of modeled spectra and their suitability for estimating spectral mismatch modifiers (SMMs) in PV systems. Preliminary results from Palaiseau show that while raw NSRDB data underestimate broadband irradiance, rescaled spectra significantly reduce spectral bias and improve SMM-based energy yield estimates. The final paper will include full results across climates and compare NSRDB performance with simplified correction models for broader application in global PV modeling.

Keywords

spectral irradiance, spectral mismatch modifier, photovoltaic performance modeling, NSRDB.

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