Conventional PV cells are made to convert light hitting the front side of the cell to electricity. With a few extra processing steps bifacial PV cells can be made so that light hitting from both sides contributes to the current produced by the cell. When placed into modules designed with transparent backsheets or glass-glass construction, bifacial PV modules are born. This idea is not new, but this technology has, thus far, remained in the fringe of the PV market. We believe that bifacial PV may begin to enter the mainstream of the PV industry in the next few years.
Ask yourself, if the first PV cell that was invented was bifacial, how would PV modules and systems be different from today’s PV technologies? We believe that bifacial PV could represent a revolutionary opportunity for increasing the efficiency and lowering the cost of solar energy systems. Field data, characterization methods and standards, and predictive models are needed.
Sandia National Laboratories, the National Renewable Energy Laboratory, and the University of Iowa are working together to better understand the performance characteristics of bifacial PV modules and systems. This work is divided into the following categories:
- Outdoor bifacial PV performance data
- Bifacial characterization and rating standards
- Performance modeling of bifacial PV systems
- Joshua S. Stein Sandia National Laboratories (Principal Investigator; Field data and modeling)
- Cliff Hansen
- Dan Riley
- Chris Deline National Renewable Energy Laboratory (Co-PI; Characterization and modeling)
- William Marion
- Sarah MacAlpine
- Silvana Ayala Pelaez
- Fatima Toor University of Iowa (Co-PI; Ray Tracing)
- Amir Asgharzadeh Shishavan
Publications and Presentations
- Riley, D. et al. 2018 Performance of Bifacial PV Modules with MLPE vs. String Inverters, WCPEC-7, Waikoloa, HI.
- Ayala Pelaez, S. 2018. Model and Validation of Single-Axis Tracking with Bifacial PV, WCPEC-7, Waikoloa, HI.
Asgharzadeh, A. 2018 A Comparison Study of the Performance of South/North-facing vs East/West-facing Bifacial Modules under Diffuse Shading Conditions, WCPEC-7, Waikoloa, HI.
- Ayala Pelaez, S. et al. 2018. Comparison of Bifacial Solar Irradiance Models with Field Validation (152 downloads) . 10th PV Performance Modeling Collaborative Workshop, Albuquerque, NM
- Asgharzadeh, A. et al. 2018. Bifacial PV System Performance: Investigation of Shading Conditions (134 downloads) . 10th PV Performance Modeling Collaborative Workshop, Albuquerque, NM
- Ayala Pelaez, S. et al. 2018. “Comparison of bifacial solar irradiance model predictions with field validation” Submitted to IEEE Journal of Photovoltaics.
- Asgharzadeh, A. et al. 2018. “A Sensitivity Study of the Impact of Installation Parameters and System Configuration on the Performance of Bifacial PV Arrays.” IEEE Journal of Photovoltaics 8(3): 798-805.
- Stein, J.S., 2018. “Solar PV Performance and New Technologies in Northern Latitude Regions“. Alaska Rural Energy Conference, Fairbanks, AK.
- Stein, J.S. et al., 2017. “Comparison of modeling methods and tools for bifacial PV performance“. 9th PV Performance Modeling and Monitoring Workshop, Weihai, China.
- Deline, C., et al., 2017. “Bifacial PV performance Models: Comparison and Field Results“. BiFiPV 2017 Workshop, Konstanz, Germany
- Hansen, C., et al., 2017. “A Detailed Performance Model for Bifacial PV Modules“. 33rd European PV Solar Energy Conference and Exhibition. Amsterdam, Netherlands.
- Stein, J. S., et al., 2017. “Outdoor Field Performance of Bifacial PV Modules and Systems“. 33rd European PV Solar Energy Conference and Exhibition. Amsterdam, Netherlands.
- Asgharzadeh, A. et al.., 2017. “Analysis of the Impact of Installation Parameters and System Size on Bifacial Gain and Energy Yield of PV Systems“. 44th IEEE PVSC. Washington, DC.
- Stein, J. S., et al., 2017. “Outdoor Field Performance from Bifacial Photovoltaic Modules and Systems“. 44th IEEE PVSC. Washington, DC. SAND2017-6464C.
- Hansen, C. W., et al., 2017,. “A Detailed Model of Rear-Side Irradiance for Bifacial PV Modules“. 44th IEEE PVSC. Washington DC. SAND2017-6554 C.
- Marion, B., et al., 2017. “A Practical Irradiance Model for Bifacial PV Modules“. 44th IEEE PVSC. Washington DC.
- Riley, D., et al., 2017. “A Performance Model for Bifacial PV Modules“. 44th IEEE PVSC. Washington, DC.
- Hansen and Riley, 2017, “Performance Model for Bifacial PV Modules”, Presentation at the 8th PVPMC Workshop, Santa Ana Pueblo, New Mexico.
- Asgharzadeh, A., et al., 2017, “Ray Tracing Models for Bifacial PV Performance“, Presentation at the 8th PVPMC Workshop, Santa Ana Pueblo, New Mexico.
- MacAlpine et al., 2017,”Progress Toward Efficient Bifacial Rear Irradiance Models”, Presentation at the 8th PVPMC Workshop, Santa Ana Pueblo, New Mexico.
- Deline, C., S. MacAlpine, B. Marion, F. Toor, A. Asgharzadeh and J. S. Stein (2017). “Assessment of Bifacial Photovoltaic Module Power Rating Methodologies – Inside and Out.” Journal of Photovoltaics,V. 7(2), p. 575-580.
- Stein et al., 2017, “Field Performance of Bifacial PV Modules and Systems”, Presentation at the 8th PVPMC Workshop, Santa Ana Pueblo, New Mexico.
- Stein, J.S., Burnham, L., and, Lave, M. (2017). 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. Albuquerque, NM, Sandia National Laboratories. SAND2017-5872.
- Deline, C., S. MacAlpine, B. Marion, F. Toor, A. Asgharzadeh and J. S. Stein (2016). Evaluation and Field Assessment of Bifacial Photovoltaic Module Power Rating Methodologies. 43rd IEEE Photovoltaic Specialist Conference. Portland, OR.
- Hansen, C. W., J. S. Stein, C. Deline, S. MacAlpine, B. Marion, A. Asgharzadeh and F. Toor (2016). Analysis of Irradiance Models for Bifacial PV Modules. 43rd IEEE Photovoltaic Specialist Conference. Portland, Oregon. SAND2016-0803 C.
Bifacial Open Source Software
- 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 (32 downloads)
Bifacial Workshops (click on links to access information and presentations)
|2018||6th Bifacial (BiFi) Workshop||Denver, USA||Workshop webpage|
|2017||5th Bifacial (BiFi) Workshop presentations||Konstanz, Germany||Workshop webpage|
|2016||4th Bifacial (BiFi) Workshop presentations||Miyazaki, Japan||Workshop webpage|
|2015||3rd Bifacial (BiFi) Workshop presentations||Antofagasta, Chile||Workshop webpage|
|2014||2nd Bifacial (BiFi) Workshop presentations||Chambery, France||Workshop webpage|
|2012||1st Bifacial (BiFi) Workshop presentations||Konstanz, Germany||Konstanz, Germany|
External Bifacial Resources and References (please send me additional references to add to this site)
- Castillo-Aguilella, J. E. and P. S. Hauser (2016). “Multi-Variable Bifacial Photovoltaic Module Test Results and Best-Fit Annual Bifacial Energy Yield Model.” IEEE Access 4: 498-506.
- Anoma, M. A., D. Jacob, B. C. Bourne, J. A. Scholl, D. M. Riley and C. W. Hansen (2017). “View Factor Model and Validation for Bifacial PV and Diffuse Shade on Single-Axis Trackers“. 44th IEEE PVSC, Washington, DC.
- SolarWorld White Paper: “Calculating the Additional Energy Yield of Bifacial Solar Modules“