Techno-economic optimization of a grid-connected solar-wind - pumped hydro hybrid system for energy and desalination...

The growing demand for electricity and fresh water in remote and coastal regions necessitates sustainable solutions that reduce reliance on fossil fuels. Hybrid renewable energy systems, which combine solar, wind, and storage technologies, have proven effective in ensuring a reliable supply and environmental sustainability. However, few studies have addressed large-scale hybrid applications that simultaneously meet electricity and desalination needs in coastal areas, and the integration of pumped-hydro storage with PV and wind in Egypt's high-potential regions is underexplored. In particular, previous work has rarely incorporated realistic mixed residential, agricultural, and desalination load profiles or applied Diversity Factors to represent actual consumption behavior. This paper investigates the techno-economic feasibility of a hybrid system integrating photovoltaic (157.6 MW), wind (166.8 MW), and pumped-hydro storage (223,661 kWh) to supply Ras Ghareb, Egypt, using HOMER Pro simulations and real data for 5000 residential homes, agricultural machinery for irrigating 2000 acres of farmland, and the power demands of a desalination plant. The optimized system achieves a Renewable Fraction of 93.8% with no unmet load. Economically, the proposed system demonstrates strong performance, with a Net Present Cost of - $94.7 million, an Internal Rate of Return of 53%, and a simple payback period of 1.9 years, driven by selling surplus power to the grid. The qualitative sensitivity trends indicate that the system remains robust under reasonable variations in resource conditions and pricing assumptions. Environmentally, the system reduces annual CO₂ emissions by 291.7 million kg, SO₂ emissions by 1.26 million kg, and NO_x emissions by 0.62 million kg. These results also provide relevant insights for ongoing national energy and water strategies, particularly regarding renewable expansion and long-duration storage in coastal regions. The findings confirm the system's technical reliability, financial feasibility, and environmental benefits, positioning the system as a scalable model for sustainable energy in remote and coastal regions.