Abstract
We investigate the impact of spectral dependence of ground surface reflectivity on albedo and rearside irradiance measurements necessary for bifacial photovoltaic (PV) module performance estimation and monitoring. Because PV modules are spectrally selective, albedo and irradiance measurements performed with common irradiance sensors may require spectral mismatch corrections when used for performance prediction. We investigate via simulation the differences in spectrally responsive albedo measured with thermopile pyranometers and crystalline silicon PV reference cells in comparison to a typical crystalline-silicon bifacial PV module. Simulations are performed for nine different representative ground surface materials using simulated solar spectra together with spectral reflectivity data distributed with the SMARTS simulation software. For the materials considered, the results show that albedo spectral mismatch relative to the bifacial module is distributed over a range of ±9.2% for thermopile pyranometers versus only ±3.7% for a typical PV reference cell. We consider the impact of this spectrally-responsive albedo mismatch on bifacial PV module rearside irradiance measurements. Using synthesized rearside spectral irradiance distributions, we find that for the nine different ground surface materials the predicted rearside irradiance measurement deviates from the effective irradiance observed by the PV module by on the order of 16.5 W/m 2 for the pyranometer and 3.6 W/m 2 for the PV reference cell. We discuss the implications for bifacial albedo and irradiance measurement.
Original language | American English |
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Number of pages | 5 |
DOIs | |
State | Published - 2021 |
Event | 2020 47th IEEE Photovoltaic Specialists Conference (PVSC) - Calgary, Canada Duration: 15 Jun 2020 → 21 Aug 2020 |
Conference
Conference | 2020 47th IEEE Photovoltaic Specialists Conference (PVSC) |
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City | Calgary, Canada |
Period | 15/06/20 → 21/08/20 |
Bibliographical note
See NREL/CP-5K00-75927 for preprintNREL Publication Number
- NREL/CP-5K00-79287
Keywords
- bifacial
- photovoltaic (PV) systems
- pyranometer
- reference cell
- resource assessment