Techno-economic analysis of various configurations of stand-alone PV-RO systems for Pakistan

The global water scarcity crisis has led to increased demand for reverse osmosis (RO) desalination technology. In response to the rising global temperatures, there is a growing focus on renewable energy sources such as solar photovoltaic (PV) and wind energy to power small-scale RO plants. This paper presents a comprehensive technoeconomic analysis of stand-alone photovoltaic reverse osmosis (PV-RO) systems in Pakistan. It focuses on the design and optimization of PV-RO systems for Karachi and Lahore, evaluating the systems with and without energy recovery devices. A parametric study was conducted to optimize system performance, considering various configurations. The analysis includes a comparison of costs when operating with PV, diesel, and grid power. It was found that for Karachi, a four-stage PV-RO system without an energy recovery device provides water at $1.359 per cubic meter, while in Lahore, a three-stage system with an energy recovery device achieves $1.336 per cubic meter. These systems offer significant annual savings compared to diesel-powered systems, with Karachi and Lahore saving up to $10,138 and $17,664 respectively over ten years. The findings of this study show that PV-RO systems, especially those with multiple stages and energy recovery devices, offer a costeffective and sustainable solution for water desalination in these regions.