Sustainable Water Production: Solar Energy Integration in Multi-Effect Desalination Plants
Ali K. Muftah, Leila Zili-Ghedira, Mabruk M. Abugderah, Walid Hassen, Nidhal Becheikh, Badr M. Alshammari, Lioua Kolsi
Abstract
This study addresses the increasing demand for sustainable water production by investigating the integration of solar energy into a multi-effect desalination (MED) plant located in Zuara, Libya. It is acknowledged that regions with high water demand frequently experience elevated levels of solar radiation; thus, this approach seeks to reduce dependence on fossil fuels and mitigate harmful emissions. Three operational modes were analyzed and compared: (1) daytime-only solar operation, (2) hybrid solar–boiler operation, and (3) solar operation with thermal energy storage. A validated mathematical model, informed by real empirical data, was used to assess energy and exergy efficiencies as well as production costs per cubic meter of desalinated water. The results indicate a trade-off between cost-effectiveness and environmental impact. The fossil fuel-based mode demonstrated the highest energy efficiency but also produced the greatest pollution. Conversely, the solar-only daytime mode, while free of emissions, was the costliest (USD 1.4/m3) due to its limited operational hours. The hybrid mode offered a compromise, presenting lower costs (USD 0.79/m3) and moderate land use, yet it still relied on fossil fuels. The thermal storage mode facilitated continuous, clean desalination at a higher cost (USD 0.97/m3) and required the largest solar field area. This study demonstrates the potential of solar-powered MED plants for sustainable water production, particularly in regions characterized by abundant sunlight and water scarcity. Furthermore, this research provides a comprehensive framework for selecting the optimal operational mode based on specific priorities, such as minimizing environmental impact, reducing costs, or maximizing operational flexibility.