July 19, 2022, 9 a.m.

Two methods of estimating photovoltaic spectral effects

Photovoltaic modules are typically rated at Standard Test Conditions that include the AM1.5 reference spectrum. Deviations from AM1.5 can lead to annual gains or losses of up to roughly 3% for crystalline silicon and 10% for amorphous silicon. Ideally, spectral effects would be derived using photovoltaic module spectral responsivity and spectroradiometer data, but this is rarely feasible. Two alternative methods are presented and discussed. The first method is the semiempirical PVSPEC model developed by CanmetENERGY and Canadian Solar, which estimates spectral mismatch factor using clear-sky index and absolute air mass. The second method uses satellite-based spectral irradiance products, namely the National Renewable Energy Laboratory National Solar Radiation Database Spectral on Demand (NSRDB-S) and Satellite Application Facility on Climate Monitoring Spectral Resolved Irradiance (CM-SAF SRI). These methods are developed and tested for six photovoltaic module technologies using spectroradiometer and meteorological data at seven ground stations.

Sophie Pelland received a Ph.D. in theoretical particle physics from Cornell University in 2001. She worked as a Senior Solar Energy Assessment Analyst at Vaisala from 2015 to 2018, where she performed probabilistic modeling of the energy yield of utility-scale photovoltaic (PV) plants worldwide and lead Vaisala’s R&D in this field. She was a Research Officer at CanmetENERGY from 2005 to 2014, and rejoined CanmetENERGY in 2018 as a Physical Sciences Specialist in the Renewable Energy Integration group. Her research interests include PV system performance and modeling, solar resources, and renewable energy integration into electricity grids.

Dr. Pelland is the Canadian representative to the International Energy Agency Photovoltaic Systems Programme Task 16 on “Solar Resource for High Penetration and Large Scale Applications”. She is also part of the Canadian committee developing international standards on non-concentrating, terrestrial photovoltaic modules within the International Electrotechnical Commission Technical Committee 82 Working Group 2.