Simultaneous optimization of power generation and desalination systems: a general approach with applications to Kuwait

There is a growing need to produce water and energy more sustainably by incorporating the following objectives: (1) enhanced solar utilization, (2) reduced fossil fuel usage, (3) increased desalination efficiency, and (4) decreased environmental emissions. This paper investigates the following hypotheses: (1) the aforementioned objectives require a novel systems-integration approach that identifies synergistic design and operational strategies, (2) the water-energy nexus must integrate power plants and desalination systems, and (3) optimal solutions must supplement existing infrastructure with emerging technologies. To reduce the carbon footprint, fossil-based power plants are augmented with solar energy. Because of seasonal variations in supply and demand for energy and water—and because of the diurnal nature of solar energy—a multi-period approach is utilized. As a result of complex water-energy interactions, a superstructure representation is created to embed potential configurations of interest. The optimization formulation incorporates multiple objectives and guides the design and operational decisions. This approach is applied to a case study on the Kuwait water-energy nexus, and considers the following: (1) seasonal variations in fuel availability, prices, power demand, and water needs; (2) multi-period optimization of fuel usage within the existing infrastructure; (3) the potential for solar retrofits; (4) the impact of several carbon-footprint constraints on the minimum cost; and (5) optimal design and operational strategies. In infrastructure renewal projects, the developed approach and targeted application can help decision-makers create simultaneous design and operational strategies that meet economic and environmental objectives. Graphical abstract: [Figure not available: see fulltext.]