Comparative numerical investigation and techno-environ-economic analysis of solar PV and onshore wind powered reverse osmosis plant for sustainable water-energy nexus

This study presents a comprehensive techno-economic assessment of a reverse osmosis (RO) plant, designed to produce 147.2 m³ of potable water per day for 100 households using renewable energy sources, namely bifacial photovoltaic (PV) and wind turbine (WT) systems, as alternatives to conventional grid electricity. A detailed numerical modeling coupled with Water Application Value Engine (WAVE) and System Advisor Model (SAM) simulation tools is utilized to evaluate the sustainable system configurations capable of meeting the RO plant with 112 kW power demand. The energetic performance of the hybrid RO plant is comprehensively evaluated under two configurations (PV-RO and WT-RO) based on energy, economic, and environmental analyses under harsh conditions in Dhahran, Saudi Arabia, for one complete year. The simulation results show that to optimistically meet the power demand of the RO plant, the PV system design is desired to be 592 mono-crystalline silicon modules with an efficiency of 21.54%, covering a total area of approximately 700 m², with an estimated capital cost of $163,895. This configuration achieved a levelized cost of electricity (LCOE) of 3.35 ¢/kWh, an internal rate of return (IRR) of 5.21%, a net present value (NPV) of $34,565, and a payback period of 12 years. In comparison, the wind-powered RO plant optimized for a 14-turbine array with a rated power of 10 kW each required a higher capital investment of $214,085. This resulted in an LCOE of 3.99 ¢/kWh, an IRR of 2.34%, and an NPV of $10,738, with a payback period of 15.4 years. For the levelized cost of water (LCOW), PV-RO results are more favorable at 0.79 $/m³ compared to $0.825/m³ for wind-RO. The carbon footprint analysis also showed that the WT-RO system emits 20.55 gCO₂/kWh, while the PV-RO system records 38 gCO₂/kWh. Both of these values are significantly lower than those of fossil fuel-based power systems. Overall, the results demonstrate that the PV-RO configuration is the preferred option when economic performance is the primary objective, owing to its lower LCOE, LCOW, and shorter payback period, whereas the WT-RO configuration offers the lowest carbon footprints and may be preferred where environmental impact is the dominant design criterion.