Sandia’s research in PV performance and reliability focuses on improving the ability of PV systems to consistently meet intended performance metrics under specific environmental conditions. Reliability testing at Sandia includes five primary tasks:
- Predictive model development
- Real-time reliability studies
- Accelerated and diagnostic testing
- Industry outreach and standards support
- Mitigation and failure analysis efforts
The lab uses field operations and maintenance (O&M), degradation studies, failure data from integrators and utility partners, and detailed statistical models to develop systems-level models. These models can be applied by researchers and industry to help determine ways to overcome reliability issues and accelerate high penetration of PV technologies. Sandia also conducts real-time degradation studies such as Accelerated Life Testing and Failure Modes and Effects Analysis. Sandia has also partnered with a utility to create a data-driven Reliability Block Diagram and gather O&M data to generate failure statistics. This input contributes to the Labs’ PV Reliability and Availability Predictive Model (PVRAM). Some key activities include the PV Performance Modeling Collaborative, Sandia PV Array Performance Model, the U.S. Department of Energy’s Regional Test Centers, and PV System Modeling and Analysis.
Bifacial PV technologies are rapidly developing and are predicted to play a key role in the future of solar energy. Current bifacial PV system designs are based on monofacial concepts and may not be optimal. Existing performance models are only beginning to predict performance of very simple bifacial systems, yet they still lack many important details. This project will: (1) develop and validate advanced bifacial performance models capable of simulating a wide range of system designs, (2) perform design optimization studies for a range of bifacial system types utilizing high performance computing resources and tools available at Sandia and National Renewable Energy Laboratory (NREL), (3) deploy and monitor typical bifacial systems for model validation, and (4) work with industry to improve standards and best practices in the areas of module and system rating, capacity testing, site prospecting, and safety.
Ayala Pelaez, S., et al., “The subtle art of bifacial performance modeling.” 12th PV Performance Modeling Workshop, Albuquerque, NM, 2019.
Ayala Pelaez, S., C. Deline, S. Macalpine, B. Marion, J. S. Stein, and R. K. Kostuk, “Comparison of bifacial solar irradiance model predictions with field validation,” IEEE J. Photovoltaics, 9, no. 1(2019): 82–88. https://ieeexplore.ieee.org/abstract/document/8534404.
Ayala Pelaez, S., C. Deline, P. Greenberg, J. S. Stein and R. K. Kostuk, “Model and Validation of Single-Axis Tracking with Bifacial PV.” Journal of Photovoltaics, 9, no. 3(2019):715-721. DOI: 10.1109/JPHOTOV.2019.2892872.
Deline, et al., “Bifacial PV System Performance: Separating Fact from Fiction.” Presented at the Plenary Session at the Photovoltaics Specialists Conference, Chicago, IL, 2019.
Liang, T. S., M. Pravettoni, C. Deline, J. S. Stein, R. Kopecek, J. P. Singh, W. Luo, Y. Wang, A. G. Aberle and Y. S. Khoo, “A review of crystalline silicon bifacial photovoltaic performance characterisation and simulation,” Energy & Environmental Science 12, no. 1(2019): 116-148. DOI 10.1039/C8EE02184H.
Marion, Bill, “Albedo Data to Facilitate Bifacial PV System Planning.” 12th PV Performance Modeling Workshop, Albuquerque, NM, 2019.
Stein, et al., “Bifacial Photovoltaic Performance Optimization Using Ray Tracing and High-Performance Computing. Keynote presentation at Photonics North, Quebec City, Canada, 2019.
Ayala Pelaez, S., et al. “Comparison of bifacial solar irradiance model predictions with field validation.” Submitted to IEEE Journal of Photovoltaics. 2018.
Ayala Pelaez, S., “Model and Validation of Single-Axis Tracking with Bifacial PV.” WCPEC-7, Waikoloa, HI, 2018. Submitted to Journal of Photovoltaics. Preprint: https://www.nrel.gov/docs/fy19osti/72039.pdf
Ayala Pelaez, S., et al., “Comparison of Bifacial Solar Irradiance Models with Field Validation.” 10th PV Performance Modeling Collaborative Workshop, Albuquerque, NM, 2018.
Asgharzadeh, A. “A Comparison Study of the Performance of South/North-facing vs East/West-facing Bifacial Modules under Shading Conditions.” WCPEC-7, Waikoloa, HI, 2018.
Asgharzadeh, A. et al., “Bifacial PV System Performance: Investigation of Shading Conditions.” 10th PV Performance Modeling Collaborative Workshop, Albuquerque, NM, 2018.
Asgharzadeh, A. et al., “A Sensitivity Study of the Impact of Installation Parameters and System Configuration on the Performance of Bifacial PV Arrays.” IEEE Journal of Photovoltaics 8, no. 3(2018): 798-805.
Hansen, et al., “Field Performance of Bifacial PV Modules and Systems.” PV Module Technology & Applications Forum, Cologne, Germany, 2018.
Hansen, et al., “Field Performance of Bifacial PV Modules and Systems.” 28th NREL Silicon Workshop, Winter Park, CO, 2018.
Riley, D., et al., “Performance of Bifacial PV Modules with MLPE vs. String Inverters.” WCPEC-7, Waikoloa, HI, 2018.
Stein, J. S. and D. C. Jordan, “Glass-Glass Photovoltaic Modules – Overview of Issues.” DuraMAT Fall Workshop, Stanford, CA, 2018.
Stein, J. S., “Solar PV Performance and New Technologies in Northern Latitude Regions.” Alaska Rural Energy Conference, Fairbanks, AK, 2018.
Asgharzadeh, A., et al., “Ray Tracing Models for Bifacial PV Performance.” Presentation at the 8th PVPMC Workshop, Santa Ana Pueblo, NM, 2017.
Asgharzadeh, A., et al., “Analysis of the Impact of Installation Parameters and System Size on Bifacial Gain and Energy Yield of PV Systems.” 44th IEEE PVSC. Washington, DC, 2017.
Deline, C., et al., “Bifacial PV Performance Models: Comparison and Field Results.” BiFiPV 2017 Workshop, Konstanz, Germany, 2017.
Deline, C., S. MacAlpine, B. Marion, F. Toor, A. Asgharzadeh and J. S. Stein. “Assessment of Bifacial Photovoltaic Module Power Rating Methodologies – Inside and Out.” Journal of Photovoltaics, 7, no. 2(2017):575-580.
Hansen, C., et al., “A Detailed Performance Model for Bifacial PV Modules.” 33rd European PV Solar Energy Conference and Exhibition, Amsterdam, Netherlands, 2017.
Hansen, C., et al., “A Detailed Model of Rear-Side Irradiance for Bifacial PV Modules.” 44th IEEE PVSC, Washington DC, 2017. SAND2017-6554 C.
Hansen and Riley, “Performance model for bifacial PV modules.” Presentation at the 8th PVPMC Workshop, Santa Ana Pueblo, NM, 2017.
MacAlpine, et al., “Progress Toward Efficient Bifacial Rear Irradiance Models.” Presentation at the 8th PVPMC Workshop, Santa Ana Pueblo, NM, 2017.
Marion, B., et al., “A Practical Irradiance Model for Bifacial PV Modules.” 44th IEEE PVSC, Washington DC, 2017.
Riley, D., et al., “A Performance Model for Bifacial PV Modules.” 44th IEEE PVSC, Washington, DC, 2017.
Stein, J. S., et al., “Comparison of modeling methods and tools for bifacial PV performance.” 9th PV Performance Modeling and Monitoring Workshop, Weihai, China, 2017.
Stein, J. S., et al., “Outdoor Field Performance from Bifacial Photovoltaic Modules and Systems.” 44th IEEE PVSC, Washington, DC, 2017. SAND2017-6464C.
Stein, J. S., et al., “Outdoor Field Performance of Bifacial PV Modules and Systems.” 33rd European PV Solar Energy Conference and Exhibition, Amsterdam, Netherlands, 2017.
Stein, et al., “Field Performance of Bifacial PV Modules and Systems.” Presentation at the 8th PVPMC Workshop, Santa Ana Pueblo, NM, 2017.
Stein, J. S., L. Burnham, and M. Lave, “One Year Performance Results for the Prism Solar Installation at the New Mexico Regional Test Center: Field Data from February 15, 2016 – February 14, 2017.” Sandia National Laboratories, Albuquerque, NM, SAND2017-5872.
Deline, C., S. MacAlpine, B. Marion, F. Toor, A. Asgharzadeh, and J. S. Stein, “Evaluation and Field Assessment of Bifacial Photovoltaic Module Power Rating Methodologies.” 43rd IEEE Photovoltaic Specialist Conference, Portland, OR, 2016.
Hansen, C. W., J. S. Stein, C. Deline, S. MacAlpine, B. Marion, A. Asgharzadeh and F. Toor. “Analysis of Irradiance Models for Bifacial PV Modules.” 43rd IEEE Photovoltaic Specialist Conference, Portland, OR, 2016. SAND2016-0803 C.
bifacial_radiance: Contains a series of Python wrapper functions from NREL to make working with RADIANCE easier, particularly for the PV researcher interested in bifacial PV performance.
bifacialvf: A self-contained view factor (or configuration factor) model from NREL which replicates a 5-row PV system of infinite extent perpendicular to the module rows. Single-axis tracking is supported, and hourly output files based on TMY inputs are saved. Spatial nonuniformity is reported, with multiple rear-facing irradiances collected on the back of each module row.
3Dbifacial_VF: Matlab functions and example scripts to model rearside irradiance using a 3D view factor approach. Able to simulate variations across individual modules in an array. Code is available here: Sandia_Bifacial-PV_View-Factor-code_0.2-1.zip (428 downloads)
Bifacial Workshops (click on links to access information and presentations)
|2018||6th Bifacial (BiFi) Workshop||Denver, USA||Workshop webpage|
Degradation Assessment of Fielded CIGS Photovoltaic Arrays: In this project, conducted at the U.S. DOE Regional Test Centers (RTCs), we are establishing outdoor performance testing protocols for CIGS PV modules and developing accurate predictive performance models.
Predicts how quickly corrosion will occur and what damage it does given certain environments and materials to PV modules. The project provides information to select the right materials for design or to develop materials for corrosion-resistance for a particular environment.
This project is focused on PV system functional safety, especially as it pertains to emergency personnel safety, using a science and engineering basis to characterize and address hazards.
Formed in 2018, PV CAMPER is an international community of research institutions committed to sharing high-fidelity meteorological and performance data in order to advance photovoltaic (PV) research and expand solar markets. To date, PV CAMPER has 10 members and a network of 13 field sites that span both hemispheres and most major climate zones.
Each member institution operates one or more field laboratories and is actively engaged in performance and reliability research. To facilitate collaboration and ensure data quality across all sites, PV CAMPER representatives have agreed to deploy similar instrumentation, methods of data collection, and O&M protocols. The result is a global network of outdoor laboratories that can be leveraged for research investigations ranging from experimentation to simulation and validation studies.
Learn more at the PV CAMPER webpage.
Started in 2016, the PV Lifetime Project is measuring PV module and system degradation profiles over time with the aim of distinguishing different module types and technology. Outdoor energy monitoring in different climates will be supplemented with regular testing under repeatable test conditions indoors. The focus will be on the PV module, as well as other hardware components attached to it (junction boxes, bypass diodes, and module-level electronics). Hardware will be installed at Sandia National Laboratories in New Mexico, at the National Renewable Energy Laboratory in Colorado, and at the University of Central Florida. The systems will be continuously monitored for DC current and voltage, as well as periodic I-V curves at the string level. Once degradation trends have been identified with more certainty, results will be made available to the public online. This data is expected to enable an increase in the accuracy and precision of degradation profiles used in yield assessments that support investments made in new PV plants.
Over 800 PV modules are currently being monitored by the program.
Fact Sheets and Key Publications:
Hansen and Jordan, Sample size guidelines for PV lifetime project, (Albuquerque, NM: SAND2017-483R, 2017).
Stein and Jordan, “Glass-Glass Photovoltaic Modules – Overview of Issues.” Fall DuraMAT Workshop, Stanford, CA, 2018.
Stein, et al., “PV Lifetime Project: Measuring PV Module Performance Degradation: 2018 Indoor Flash Testing Results.” WCPEC-7, Waikoloa, HI, 2018.
Stein et al., “PV Lifetime Project – Challenges of Measuring PV Module Degradation.” 2018 PV Module Reliability Workshop, Denver, CO, 2018.
Stein, J. S. “Challenges of PV Degradation Analysis: PVLIB and Performance Data Analysis.” Fall DuraMAT Workshop, Albuquerque, NM, 2017.
For more information, visit: pv-lifetime-modules/.
The PV Performance Modeling and Stakeholder Engagement project is a core capability including development, implementation, and validation of new performance sub-models in the areas of module thermal behavior, dynamic soiling, degradation, and stakeholder engagement through the PV Performance Modeling Collaborative (PVPMC) and International Energy Agency Photovoltaic Power Systems (IEA PVPS) program.
PVPMC brings together researchers from academia and industry to share the latest ideas to accurately model and predict the performance of PV systems in the field. The PVPMC has held ten workshops in four countries, hosts a website that receives over 10,000 views/month, and shares open-source software to over 6,000 users worldwide. We will continue this effort through 2021.
The mission of the IEA PVPS program is to enhance international collaboration involving photovoltaic solar energy as a cornerstone in the transition to sustainable energy systems. The objective of Task 13 is to improve the reliability of photovoltaic systems and subsystems by collecting, analyzing and disseminating information on technical performance and failures, providing a basis for assessment, and developing practical recommendations for sizing purposes. Sandia National Laboratories’ Joshua Stein represented the USA in this working group from 2014-2017 and will continue in the role through 2021. Stein will provide leadership in this group as a Task Leader for Task 1. In addition, this task will collect and deliver open-source PV performance datasets from around the world and help extend DuraMAT research to an international stage.
Prillman, M., “Finite Element Thermal Analysis Supporting a Transient Moving-Average Module Temperature Prediction Model.” Paper presented at the 12th PV Performance Modeling and Monitoring Workshop, Albuquerque, NM, May 2019.
Sandia is working to incorporate the PV Reliability Performance Model (PV-RPM) into the System Advisor Model (SAM) to improve PV performance model capabilities when considering component-level reliability.
Snow and ice accumulation on the front surface of photovoltaic (PV) panels is a recognized contributor to lifetime PV performance and reliability, and energy losses attributable to ice and snow are a growing concern.
This three-year project aims to increase the performance and resilience of PV systems deployed in regions of the US that regularly experience below-freezing precipitation, thus aiding in the adoption, integration and optimal operation of the nation’s solar resources.
Learn more at the SNOW project webpage.