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A comparison between monofacial and bifacial PV systems in Ghana showed how changes in system parameters can affect bifacial gains. The researchers found that changing the albedo of a ground system can increase bifacial gain from 5.25% to 14.5%.
Scientists from the Kwame Nkrumah University of Science and Technology in Ghana, the Bui Power Authority and the Norwegian University of Life Sciences have evaluated the performance of existing and simulated terrestrial and floating monofacial solar installations in Ghana and compared them with the energy performance of simulated bifacial systems of the same dimensions and design.
The existing facilities are a 50 MW terrestrial photovoltaic installation and a 400 kW floating photovoltaic array. Both are connected to the 404 MW Bui Dam hydroelectric plant.
“One of the main scientific knowledge gaps missing from the literature review is the lack of comprehensive data on the performance of terrestrial and floating solar PV systems (monofacial and bifacial) specifically designed and tested in the low-latitude regions of West Africa. ”, the researchers highlighted. Using different approaches to solar integration in the hydropower plant, the group tried to determine the optimal system parameters to improve performance.
The groups evaluation results show that the gain of non-optimized bifacial ground PV systems and bifacial floating PV (FPV) systems is 2.51% and 4.57%, respectively, compared to their monofacial counterparts. The researchers noted that while this was not significant enough to justify installing a new system, additional gains could be made by optimizing the systems features.
For example, changing the ground albedo of a gravel ground PV system to a white surface increased the bifacial gain from 5.25% to 14.5%. The team also determined that the optimal tilt angle for bifacial and FPV terrestrial PV systems was 15% to achieve maximum annual power generation of 79.5 GWh and 620.9 MWh respectively.
For the study, Bui Power Authority obtained meteorological data measured daily in 15-minute steps for 2022, including global horizontal irradiance over a horizontal surface, ambient temperature and wind speed. Buis available power generation data for the operational 400 kW monofacial FPV system covers the period from September 2022 to February 2023, while the power data generated by the 50 MW land-based monofacial system is from the entire year 2022.
The researchers used the System Advisor Model (SAM) tool and a modified weather file from the National Solar Radiation Database to simulate the performance of a bifacial FPV system over water and land. Based on the evaluation, the team found that to obtain the best performance and increase the bifacial gain, the parameters of albedo, inclination angle and ground cover ratio should be 0.5, 15 and 0.3 respectively.
“With 1% of the total surface of water bodies in Africa, FPV has the potential to generate 101 GWp of energy, an annual addition of 46.04 TWh and water savings of 743 million m3/year,” they stressed. the academics. “The installation of floating photovoltaic panels (FPV) on hydropower reservoirs could help stabilize hydropower generation during dry seasons, decrease evaporation losses, improve energy efficiency and support the populations growing energy demand. rapidly expanding African country.
The full results of the evaluation are available in the study “ Comparison of ground-based and floating solar photovoltaic systems performance based on monofacial and bifacial modules in Ghana – ScienceDirect ” bifacials in Ghana – ScienceDirect), published in Energy Nexus . The scientists recommended that economic analyzes be performed due to the difference in costs between monofacial and bifacial PV modules. |
