Solar Desalination in the Southwest United States: A Thermoeconomic Analysis Utilizing the Sun to Desalt Water in High Irradiance Regions

Abstract

Water scarcity and high irradiance overlap in the southwestern United States. This thesis explores solar energy as a method to power desalination in the Southwest. Ten solar desalination plants were modeled using photovoltaic reverse osmosis and concentrated solar thermal multi-effect distillation. Seawater and brackish water were considered, as well as liquid and zero liquid discharge plants. Using borrowed capital amortization, levelized energy costs were estimated to be 0.067 $/kWh-electric for photovoltaic systems and 0.009 $/kWh-heat for thermal systems. Photovoltaic reverse osmosis with liquid plant waste showed the best short-term financials while optimal long-term solar desalination methods were shown to be arbitrary, limited by solar conversion and desalination thermodynamics. A conceptualization and proof of desalination minimum work is presented. This study concludes that solar desalination cost remains higher than conservation, but has considerable potential as a new source of water in the Southwest, filling the gap between overdraft and renewable supply.