This study assessed six tomato (Solanum lycopersicum L.) cultivars within an integrated solar-powered closed hydroponic system in Al Dhaid, UAE (25 degrees 16 ' 11.2 '' N, 55 degrees 55 ' 52.2 '' E). The system combined an insect-proof net house, closed hydroponics, root-zone cooling, ultra-low-energy drip irrigation, and a cost-effective solar-powered reverse osmosis (RO) desalination unit to address salinity constraints. The cultivars, selected for their adaptability to controlled environments in the UAE, were evaluated for yield, water-use efficiency (WUE), and fertilizer-use efficiency (FUE). Among them, Torcida recorded the highest mean yield (0.619 kg/m2/harvest), WUE (27.1 kg/m3), FUE (26.5 kg fruit/kg fertilizer), and marketable fruit ratio (66.3%), followed by Roenza, Eviva, and SV 4129 TH; Lamina was intermediate, while Saley, a bushy type, produced the lowest yield. The top cultivars achieved cumulative yields exceeding 7 kg/m2-surpassing regional open-field benchmarks (4-5 kg/m2; 3-6 kg/m3). Compared with conventional cooled hydroponic greenhouses (3.5 kg/plant; 8 kg/m3), the system demonstrated similar productivity using three times less water. The RO unit produced water at baseline 1.05 USD/m3-58-68% below regional tariffs-while minimizing reliance on grid electricity and mechanical cooling. Overall, the integrated solar-powered hydroponic-RO model proved technically reliable, resource-efficient, and economically viable, offering a scalable solution for sustainable vegetable production in hyper-arid regions.