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The potential for application of photovoltaic (PV) technology in irrigated agriculture has increased in recent years due to a wider availability of affordable PV modules, and a desire to reduce dependencies on conventional non-renewable energy sources. The irrigation management strategy determines the frequency and duration for which pumping is required, thus influencing the PV system sizing. The objective of this research is to investigate the variability of PV system sizing with alternate irrigation management strategies. A model interlinking the daily crop water requirement, the soil moisture status, the irrigation requirement, the power production from the PV array, the power used by solar pumps, and the state of charge of the battery bank was used for determining the reliability of a chosen PV system size under variable operating and meteorological conditions. The model was used for determining the PV sizing requirement to achieve a desired reliability for operating a 1.4 ha center pivot installed in Outlook, Saskatchewan, Canada considering a typical, moderate application depths (20-35 mm) as well as more frequent light irrigations (5-8 mm) management strategies. The strategy of using frequent light irrigations required a significantly smaller PV system than the standard soil moisture threshold based strategy to achieve the desired reliability. These results emphasize that the chosen irrigation management strategy can have a significant impact upon the economic and technological feasibility of a PV irrigation system. The modeling tools demonstrated here can be used to determine the optimum size of the PV irrigation systems while taking into consideration the interrelated factors of irrigation management, soil water characteristics, and climatic variations. |
