Techno-economic evaluation of solar photovoltaic-powered reverse osmosis desalination for different locations in Saudi Arabia

Water scarcity is a critical issue in arid regions, particularly in Saudi Arabia, where conventional freshwater sources are limited. This study presents a techno-economic investigation of the optimal design and performance of a multi-stage photovoltaic-powered reverse osmosis (PVRO) system across various Saudi cities under different operational conditions. Key parameters, including daily permeate production, recovery ratio, feed water salinity, and the number of RO stages, are analyzed to identify configurations that minimize specific water costs while ensuring efficient energy use. The results show that increasing permeate production from 3 to 24 m³/d leads to higher energy requirements and specific water costs, with Abha's water cost, for example, rising from $0.515/m³ to $0.676/m³. Recovery ratio optimization improves system efficiency, with water costs in Abha decreasing from $0.822/m³ at 15 % to $0.428/m³ at 45 %. The study also reveals that increasing the number of stages reduces energy consumption and specific water costs by enhancing water recovery. For instance, in Abha, shifting from a one-stage to a four-stage configuration reduces specific water costs by 29.6 %, from $0.761/m³ to $0.536/m³. Feed water salinity significantly impacts performance, with input power increasing by 86.4 % as salinity rises from 25,000 ppm to 55,000 ppm. These findings highlight the importance of optimizing panel and battery configurations to balance capacity and efficiency. The study underscores the need for tailored PVRO designs that account for local environmental conditions, such as solar irradiance and water quality.