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Researchers have simulated the operation of a bifacial PV system and reversible PEM fuel cells at restaurants in five US states. Taking into account the different profit rates on the back end of bifacial PV, they found that the LCOE was as low as $0.029 per kWh.
An international research group has simulated the coupling of bifacial photovoltaic panels with proton exchange membrane (PEM) reversible fuel cells (RFCs) to power commercial buildings.
The simulation was conducted at five locations in the United States: Tucson (Arizona), Los Angeles (California), Denver (Colorado), Dallas (Texas) and Minneapolis (Minnesota).
“One of the most striking results of the research is the significant cost reduction achieved by increasing the bifacial PV gain,” corresponding author Ahmad Mayyas told pv magazine . “This improvement reduced the levelized cost of electricity (LCOE) by 16%, the levelized cost of hydrogen (LCOH) by 14%, and the levelized cost of storage (LCOS) by 13%.” Another striking finding is the system’s adaptability to different climates – from the arid conditions of Tucson to the colder environment of Minneapolis – demonstrating not only significant energy efficiency improvements but also remarkable cost-effectiveness in diverse geographic locations.”
Energy demand data for the locations were obtained from the U.S. Department of Energy’s National Renewable Energy Laboratory (NREL), assuming full-service restaurants with average hourly load demand of 20.33 kWh, 27.87 kWh, 116.98 kWh, 46.62 kWh, and 32.51 kWh in Dallas, Denver, Los Angeles, Minneapolis, and Tucson, respectively. Meteorological data for these regions were obtained from the National Solar Radiation Database, which shows that global horizontal irradiance (GHI) ranges from 1,400 kWh/kWp/yr to 2,100 kWh/kWp/yr.
The bifacial PV system was simulated under different rear gain conditions of 0%, 5%, 10% and 20%. The system was assumed to supply power to the building, while surplus energy was used to produce hydrogen or sold to the grid if the hydrogen tank was full. When solar power is lacking, the reversible fuel cells come into action, producing electricity to meet the restaurant load. In case hydrogen runs out, the grid supplies electricity.
“Optimal sizes from the grid search optimisation technique were identified by carefully considering factors such as grid impact, capital costs and compliance with net metering principles,” the academics explain. “The primary objective of determining optimal sizes was to minimise excess energy export to the grid. Sizes larger than optimal could place unnecessary burden on the grid and increase capital costs.”
According to the optimization, the PV system capacity in Tucson was 300 kW, in Los Angeles 1,200 kW, in Denver 350 kW, in Dallas 300 kW, and in Minneapolis 900 kW. The electrolyzer/fuel cell sizes were 200/84.5 kW, 700/296.1 kW, 200/84.5 kW, 200/84.5 kW, and 400/169.2 kW, respectively. The inverter sizes were 100 kW in Tucson, 300 kW in Los Angeles, 100 kW in Dallas and Denver, and 200 kW in Minneapolis. The hydrogen tanks were 150 kg, 500 kg, 150 kg, and 250 kg, respectively.
“Increasing PV gain was shown to be a powerful lever for optimizing economic efficiency. In the Tucson area, which has a high GHI, the LCOE of PV systems is $0.034 per kWh for PV systems without bifacial gain,” the researchers stated. “However, at 20% bifacial PV gain, the LCOE decreases to $0.029 per kWh. Similarly, in Minneapolis, which has the lowest GHI, the LCOE of standard PV systems is $0.051 per kWh, decreasing to $0.043 per kWh with bifacial gain.”
Furthermore, the researchers found that for LCOH, there is a reduction of $0.6 per kg with increasing PV gain across all regions. “For LCOS, there is a reduction of $0.06 per kWh, and the overall system LCOE shows a reduction of at least $0.02 per kWh across all regions analysed,” they also explained.
Their findings were presented in “ Harvesting energy horizons: Bifacial PV and reversible fuel cells unite for sustainable building solutions,” published in the International Journal of Hydrogen Energy . The research was carried out by scientists at the Lawrence Berkeley National Laboratory in the United States, the US Army Corps of Engineers and the Khalifa University of Science and Technology in the United Arab Emirates. |
