Presentation Details
| Sensitivity of Bifacial PV Performance Loss Rate Estimates to Rear-Side Irradiance Sensor Type and Placement: A Field Case Study Gustavo Nofuentes 1, Jorge Aguilera1, Emilio Muñoz-Cerón1, Douglas Lamas2, Giuliano A.Rampinelli2, Juan de la Casa1. 1PV IDEA Research Group, CEACTEMA, University of Jaen, Spain., Jaen, Spain.2Nucleo Tecnologico de Energia Eletrica, Federal University of Santa Catarina, Brazil., Ararangua, Brazil |
Abstract
Bifacial photovoltaic (bPV) technology is now mainstream (≈65% of global module market share in 2024, with projections near 80% by 2035), increasing the need to quantify its long-term field behavior and representative values of performance loss rate (PLR, in %·y⁻¹). Yet reliable PLR studies for bPV remain scarce because in-plane rear-side irradiance is difficult to measure in a way that is both stable and representative; otherwise, changes in albedo, geometry, or rear-side irradiance nonuniformity may be misinterpreted as degradation. Although prior work has primarily used rear-facing reference cells (remote or collocated) or horizontal albedometers combined with modeling, the influence of rear-side irradiance sensor type and placement on PLR estimates is still poorly understood. This work helps address that gap via a dedicated field case study of a two-string bPV system (1.64 kW per string) monitored over 30 months at the University of Jaén (Spain). Monthly DC bifacial performance ratio and PLR were evaluated using the rear-facing pyranometer of a coplanar albedometer and calibrated reference modules placed near the row center and at row edges of one string. PLR was confidently estimated as −1.73 ± 0.64 %·y⁻¹ for one string and −2.97 ± 0.80 %·y⁻¹ for the other, according to the YoY method. PLR derived from the albedometer rear-facing pyranometer was consistently less negative than that obtained using reference modules, with edge-mounted reference modules yielding the most negative estimates. These results underscore the need for caution and support deploying redundant rear-side irradiance sensors to improve PLR estimates robustness.
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No part of this publication may be reproduced, distributed, or transmitted in any form or by any means, including photocopying, recording, or other electronic or mechanical methods, without the prior written permission of the author.