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The lack of clean water and access to energy are two major obstacles to global sustainable systems. The development of solar photovoltaic (PV) technology gained the attention of water desalination projects due to its cost decline, carbon-free emission, and the on-site energy production. However, studies on in-depth analysis of the performance of these systems remain rare. This study performs a comprehensive a design optimization and seven-factor analysis (energy, exergy, economic, environmental, energoeconomic, exergoeconomic, enviroeconomic - 7E) of a grid-tied PV system powering a large-scale seawater reverse osmosis (SWRO) plant. First, an optimal design model is developed based on real hourly measured data for the SWRO load demand and renewable resources, while considering net energy metering mechanism. The objective function is delineated to diminish the energy cost of the system, concomitant with the imposition of operational constraints. Second, an analytical model is established to perform exergetic calculations for the optimal design. Third, a sensitivity analysis is conducted to show how the model parameters affect the system design and costs. The results show that the optimal system relies on a 4.25 MW solar PV array and a 3.125 MW grid-tied inverter. This configuration reduces the levelized cost of energy by 48.3 % and carbon emissions by 50 % compared to a grid-only system. The implementation of net-metering has also maximized the designed system's revenues to 263,834 $/year. Further, the optimally designed system achieves a lower levelized cost of water (0.2217 $/m3), minimal capacity shortage, and negligible unmet load ratios (0.048 %) despite grid outages. From the exergetic assessment, the proposed system has a high exergy efficiency (9.3 %) which can be achieved despite the high value of the exergy loss. Moreover, the energoeconomic and exergoeconomic indicators have recorded tiny values (3.35E-5 kWh/$ and 0.0311 kWh/$, respectively), which are considered a desired outcome. Notably, a profit of 4285.4$ is achieved through the sale of carbon emissions reduction. The sensitivity analysis revealed an increase in the system's total cost of 4.91 % and 9.36 % and the system's energy cost of 4.91 % and 8.7 % if the energy purchase price raised by 10 % and 20 %, respectively. Also, it indicates that a fall in the electricity sellback rate of 10 % would remarkably raise the system's energy cost by 47.3 %. Finally, reducing the PV-Inverter costs by 15 % would drop the system's net present and energy costs by 51.4 % and 60 %, respectively. Overall, the insights from this study have the potential to expedite the realization of sustainable development goals 6, 7, and 13, particularly in developing nations abundant in solar energy resources. • A design optimization model for a grid-tied solar PV-powered SWRO systems is proposed. • An energetic calculations model for a comprehensive 7E analysis is developed. • Proposed system reduced energy cost to 0.0393$/kWh and water cost to 0.2217$/m3. • Achieved high exergy efficiency (9.3 %) and favorable energy economic and indicators • Sensitivity analysis reveals that lower PV-inverter costs cut energy cost by 60 %. [ABSTRACT FROM AUTHOR]

• Solar-wind-diesel hybrid system is proposed for a large-scale reverse osmosis desalination plant. • A 3E fuzzy decision-making optimization model is developed for ten distinct energy systems. • Performance of flow batteries and pumped hydro storage technologies are investigated and compared. • Hybrid system with battery option results in better energy, economic, and ecological benefits. • Sensitivity analysis on storage cost show more savings in NPC and COE with pumped hydro than the battery. This paper aims to propose a conceptual design model for sustainable hybrid renewable stand-alone energy system (HRSES) to meet the electricity demand of a large-scale reverse osmosis desalination plant in Baltim, Egypt. The model investigates the feasibility of different HRSES alternatives and develop a fuzzy-based multicriteria decision-making model for meticulously selecting the optimal energy solution. Both zinc-bromine flow battery and turbine-pumped hydro energy storage technologies are integrated independently with wind, solar, and diesel power sources. Firstly, the proposed model uses HOMER software to execute an energy-economic-ecological optimization analysis for studying the practicability and components sizing of nine HRSES alternatives. Second, an integration between Fuzzy-AHP and Fuzzy-VIKOR decision-making methods is executed to choose the best design considering ten performance criteria. In the second stage, the fuzzy environment is engaged to expedite decision-makers to express their ratings in linguistic terms and to achieve more sensible and accurate results. Among ten feasible alternatives, the results reveal that the optimal system consists of 5 × 20-kW wind turbines, 328-kW photovoltaic array, 100-kW diesel generator, 112 batteries and 235-kW converter. This system has the best economic performance among all alternatives with least NPC, COE, and payback-period of $1,048,046, 0.101$/kWh and 1.1 yr, respectively. Besides, it has a treasured share of renewable of 95.55%; hence, it produces a realistic CO 2 of 25,426.46 kg/year. Lastly, the sensitivity analysis illuminates that the future load growth and low-interest rate hurt upcoming investments while the projected reduction in the cost of energy storages has an encouraging influence on financing decisions. [ABSTRACT FROM AUTHOR]

• Large-scale reverse osmosis desalination powered by hybrid renewable energy source. • The optimal off-grid power system was photovoltaics/wind/diesel/battery/convertor. • The emitted carbon dioxide of the optimal system outperformed diesel system by 81.5%. • Energy storage systems are required to meet the energy demand during night times. Seawater desalination is a viable source of potable water, particularly for the coastal and remote areas. However, their sustainability is limited by the intensive energy demand of the present methods. Renewable energy is an inexhaustible source of energy, accompanied by cost reduction benefits and clean power generations. Seawater desalination powered with renewable energy sources is being attractive, mainly if the utility-grid is absent. This paper aims to design a renewable energy system, to meet the electrical load demand of large-scale reverse osmosis desalination plant (1500 m3/d), and to find the optimal sizing and techno-economic and environmental feasibility assessment of several off-grid power systems. Two off-grid scenarios with different combinations of hybrid power systems were proposed and compared with the base-case of diesel. The first scenario consists of a photovoltaic, wind turbine, diesel, and generator, while the second scenario is equipped with battery storage devices. A total of eleven hybrid renewable energy systems were modelled, analyzed, and compared with the aid of HOMER Pro software to identify the best performance and the optimal plan configuration. The optimization results show that the proposed photovoltaic/wind/diesel/battery/convertor system outperformed the other alternatives and exhibited reduction potential of 60.7%, 73.7%, 62% and 81.5% lower than the existing diesel with regards to the net present cost, renewable fraction, cost of energy, and carbon dioxide emission, respectively. The optimum case consists of 451 kW solar panels, 25 wind turbines, 250 kW diesel power, battery storage of 352 string, and 358 kW system converter. The results obtained by the optimal plan with low cost and environmental protection aspects would provide a new sight for real field applications of large scales reverse osmosis applications. [ABSTRACT FROM AUTHOR]