Edoardo Teresi, Cristian Chiavetta, Gabriele Freni, Letizia Caroscio, Alessandra Bonoli
ABSTRACT Freshwater scarcity is intensifying in Mediterranean regions due to population growth, tourism, intensive agriculture, and climate-driven hydrological stress. In parallel, countries highly dependent on energy imports and lacking resilient water infrastructure face structural disruptions in water supply. While seawater desalination has emerged as a viable solution worldwide, its deployment remains limited in several regions due to cost and energy constraints. This study assesses the techno-economic feasibility of integrating renewable energy into seawater desalination to support an affordable and sustainable water supply. A Life Cycle Costing approach is applied to a 12,500 m 3 /day seawater reverse osmosis plant operating under six alternative energy configurations. Energy modeling is conducted using HOMER Pro, based on updated regional economic and environmental data. The analysis provides the first comprehensive techno-economic assessment of hybrid solar-wind-grid solutions for Mediterranean desalination, demonstrating that optimized renewable oversizing can significantly reduce water costs without relying on energy storage. Results indicate that renewable-powered scenarios can reduce the Levelized Cost of Water by up to 20% compared to grid-only systems, while improving resilience to fossil fuel price volatility. The most cost-effective scenario performs competitively with conventional municipal water tariffs and remains significantly more economical than emergency alternatives. Using a Mediterranean case study (Gela, Italy) as a reference, this work demonstrates the potential for renewable-powered desalination to support secure, low-carbon, and climate-resilient water supply in energy-constrained and water-stressed regions worldwide.