Vertical bifacial solar farms: Physics, design, and global optimization
KAUST DepartmentElectrical Engineering Program
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AbstractThere have been sustained interest in bifacial solar cell technology since 1980s, with prospects of 30–50% increase in the output power from a stand-alone panel. Moreover, a vertical bifacial panel reduces dust accumulation and provides two output peaks during the day, with the second peak aligned to the peak electricity demand. Recent commercialization and anticipated growth of bifacial panel market have encouraged a closer scrutiny of the integrated power-output and economic viability of bifacial solar farms, where mutual shading will erode some of the anticipated energy gain associated with an isolated, single panel. Towards that goal, in this paper we focus on geography-specific optimization of ground-mounted vertical bifacial solar farms for the entire world. For local irradiance, we combine the measured meteorological data with the clear-sky model. In addition, we consider the effects of direct, diffuse, and albedo light. We assume the panel is configured into sub-strings with bypass-diodes. Based on calculated light collection and panel output, we analyze the optimum farm design for maximum yearly output at any given location in the world. Our results predict that, regardless of the geographical location, a vertical bifacial farm will yield 10–20% more energy than a traditional monofacial farm for a practical row-spacing of 2 m (corresponding to 1.2 m high panels). With the prospect of additional 5–20% energy gain from reduced soiling and tilt optimization, bifacial solar farm do offer a viable technology option for large-scale solar energy generation.
CitationKhan MR, Hanna A, Sun X, Alam MA (2017) Vertical bifacial solar farms: Physics, design, and global optimization. Applied Energy 206: 240–248. Available: http://dx.doi.org/10.1016/j.apenergy.2017.08.042.
SponsorsWe gratefully acknowledge Dr. C. Deline from NREL who read the initial draft of the paper and highlighted the importance of bypass diodes regarding the energy yield of bifacial farms. This work was made possible through financial support from the National Science Foundation through the NCN-NEEDS program, contract 1227020-EEC and by the Semiconductor Research Corporation, the US-India Partnership to Advance Clean Energy-Research (PACE-R) for the Solar Energy Research Institute for India and the United States (SERIIUS), U.S. Department of Energy under Contract No. DE-AC36-08GO28308 with the National Renewable Energy Laboratory, the Department of Energy under DOE Cooperative Agreement No. DE-EE0004946 (PVMI Bay Area PV Consortium), and the National Science Foundation under Award EEC1454315-CAREER: Thermophotonics for Efficient Harvesting of Waste Heat as Electricity.