Addressing water scarcity and energy sustainability through PV-desalination systems: A case study on the southern coast of Iran

Water scarcity, particularly in tropical climates, has made the development of alternative solutions, such as desalination technologies, inevitable. However, challenges such as energy supply, the cost of produced water, and the emissions associated with the power supply method must be optimized to make desalination plants more cost-effective and environmentally friendly. This study provides a comprehensive technical, economic, and environmental assessment of a photovoltaic-reverse osmosis (PV-RO) desalination plant in a tropical climate. By analyzing different installation capacities, the developed model aims to maximize the solar fraction (SF) and minimize energy costs under the economic conditions of Iran. For the case study of the RO plant, two load profiles were analyzed, with results showing that operating the RO plant with higher capacities during daylight hours leads to better economic and environmental performance compared to 24-hour operation with a mid-range capacity. In the optimum scenario, the results show that by installing 14.75 MW of PV panels, the demand for 25,000 m³ of fresh water can be met, while the total renewable energy production equals the energy demand of the desalination plant. The SF of this grid-connected system reaches 92 %, and by selling the 8 % excess power to the grid, the final levelized cost of energy (LCOE) is reduced to $0.062/kWh, with the levelized cost of water (LCOW) reaching less than $0.35/m³. Additionally, the proposed system reduces grid dependency by >80 %, preventing over 205,000 tons of CO₂ emissions over 20 years of freshwater supply.