Photovoltaic utility-scale grid-connected power generation facilities have performance guarantee bases that often include a reference solar spectrum. EPC contractors are obligated to correct tested performance for solar spectrum, as is done for irradiance and cell temperature, to judge whether contractual performance guarantees have been satisfied. Air mass correlated with solar spectral irradiance offers a convenient way of accomplishing this. This paper offers an improvement in the versatility and accuracy of accounting for spectral effects in this manner. The effects on the spectral composition by atmospheric constituents, like aerosols and water vapor, are investigated. Spectral mismatch curves are derived that characterize the responses of the PV modules and the irradiance measurement device to both the estimated test and the reference solar spectra. Comparison of several supplier performance curves and spectral mismatch curves reveals significant discrepancies. An improvement in accuracy is proposed by the use of supplier spectral response data and estimated solar spectral profiles. Correcting for spectral effects has minimal impact at air mass values near the 1.5 reference value, but grows in significance with increasing air mass. Greater precision in accounting for solar spectral effects on PV plant performance is expected as this segment of the power generation industry matures. This paper proposes a methodology that addresses this expectation.
- Power Division
Spectral Mismatch Correlated With Air Mass Under Varying Clear Sky Conditions for Photovoltaic Facilities With Crystalline-Silicon Modules: Solar Spectral Effects — An EPC Contractor’s Perspective
Johnston, P. "Spectral Mismatch Correlated With Air Mass Under Varying Clear Sky Conditions for Photovoltaic Facilities With Crystalline-Silicon Modules: Solar Spectral Effects — An EPC Contractor’s Perspective." Proceedings of the ASME 2014 Power Conference. Volume 2: Simple and Combined Cycles; Advanced Energy Systems and Renewables (Wind, Solar and Geothermal); Energy Water Nexus; Thermal Hydraulics and CFD; Nuclear Plant Design, Licensing and Construction; Performance Testing and Performance Test Codes; Student Paper Competition. Baltimore, Maryland, USA. July 28–31, 2014. V002T09A020. ASME. https://doi.org/10.1115/POWER2014-32200
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