Towards Green Desalination: A Multi-Site Analysis of Hybrid Renewable Energy Integration in Saudi Arabian RO Plants

The integration of hybrid renewable energy systems (HRES) with reverse osmosis (RO) desalination plants presents a promising solution for sustainable water production, particularly in regions facing water scarcity and possessing a high renewable energy potential. This study conducts a comprehensive analysis of HRES optimized for 14 RO desalination plants across Saudi Arabia, addressing the critical need for techno-economic optimization in this context. The optimized systems demonstrate consistent renewable energy fractions ranging from 31 % to 36 % across various locations, with Duba achieving the highest value at 35.99 %. Total installed capacities vary widely from 3.022 MW in Farassan to 287.94 MW in Khobar, reflecting diverse local conditions and energy demands resulting from a wide interval of water capacity productions. Despite this variation, the Cost of Energy (COE) remains competitive across all projects, ranging from $0.0700/kWh to $0.0783/kWh. A detailed case study of Ras Al Khair, the only site incorporating wind turbines, reveals a 31.82 % renewable fraction with 47.7 MW PV and 45.5 MW wind capacity. Sensitivity analyses at this site indicate that increasing the renewable fraction from 0 % to 60 % raises the Net Present Cost (NPC) from $509 M to $685 M at 2 kWh/m(3) process energy intensity, with a dramatic spike to $2320 M at 80 % renewable fraction. While significant grid interaction persists, with annual purchases ranging from 311 GWh to 829 GWh, the study demonstrates that increasing renewable fractions can lead to long-term cost savings. These findings provide valuable insights for decision-makers and establish guidelines for implementing next-generation RO power plants in KSA, offering a framework applicable to countries facing similar challenges in water scarcity and energy transition.