Global Site Selection for Hybrid Solar Thermal Desalination: Advancing the Energy-Water Nexus with Open-Source Tools

Abstract

Solar desalination leverages renewable energy to advance SDG 6 (Clean Water and Sanitation) and SDG 7 (Affordable and Clean Energy), addressing energy consumption and water scarcity challenges. Despite advancements in using solar energy for desalination technologies like multi-effect distillation (MED), large-scale implementation remains limited due to site requirements. Concentrated solar power (CSP) plants need dry, sun-rich land near an electrical grid, while desalination needs proximity to water bodies and demand. Hence, collocating CSP with MED necessitates balancing resource demands such as climate, market dynamics, land topography, water availability, infrastructure, land use, and increased frequency of disaster risk due to global warming. This work focuses on these challenges from a site techno-economic perspective, developing an open-source multi-dimensional tool that integrates Geographic Information Systems (GIS) data, the System Advisor Model (SAM), an in-house techno-economic model, and multi-criteria decision-making (MCDM). This tool assesses site feasibility across resolutions from 0.5 to 50 km. Simulations under current climate conditions identified 61 countries with suitable locations for CSP-MED plants, with 60% of the sites located in Australia, the United States, Mexico, South Africa, Egypt, Spain, and Namibia. Dynamic simulations under different carbon emissions scenarios (low, medium, and high) for 2030 and 2050 demonstrate that climate change will only minimally impact the feasibility of CSP-MED processes, with payback periods increasing by a maximum of 6 months under high carbon emission scenarios. Overall, it is expected that the developed tool can be used to assist with national and state/provincial-level strategic planning for deploying large-scale solar-desalination projects.

Keywords: Solar desalination, energy-water nexus, concentrated solar power, multi-effect distillation