A systematic review on the economic viability of solar desalination: influence of design innovations and enhancement strategies

Solar desalination is one of the well-known renewable-based systems for generating drinking water from wastewater. Although solar desalination systems have been widely investigated, a thorough economic assessment covering both active and passive configurations remains limited. The main capabilities of these systems are environmental friendliness, portability, easy operation, and low construction cost. The optimal design of a solar desalination unit aims to achieve high water productivity while minimizing the cost of produced water. A decrease in water generation in solar stills leads to an increase in the cost per liter (CPL) of the application. The fabrication cost and lifespan of solar desalination systems play crucial roles in decreasing the CPL and improving the benefit–cost ratio (BCR). Over the past decades, the economic analysis of these systems has gained significant importance for their optimization. This study reviews the economic aspects of solar desalination systems, including primary and operating costs, lifespan, BCR, and CPL, while considering water production rates and the geometric design of both active and passive configurations. Moreover, a detailed review of previous research is provided to offer a clearer understanding of cost-effective system designs. Some studies show that although enhancement techniques generally improve the productivity of solar stills, in certain cases they may have little or even negative effects on reducing the cost per liter. Additionally, poor system design and the use of high-cost enhancement methods can increase the CPL rather than reduce it.