Brackish groundwater and solar energy for desalination plants

Water scarcity is a global problem that affects the quality of life and socio-economic activities. In this sense, the desalination of seawater and brackish groundwater founded in coastal plains and in the interior basins of arid regions, has become a viable option to obtain water both in quality and quantity. However, in coastal plains, the selection of the water intake site for the operation of reverse osmosis desalination systems is of special interest. Seawater can be captured through wells near the coast, designed in such a way that all or most of its flow comes from the sea. Beach wells have advantages over direct intake wells, since there is better sediment filtering which reduces costs in pretreatment and savings in membrane cleaning, and less energy requirement in the process because fewer salinity. If hydrogeologic conditions of the aquifers are known this is an innovation for the must water intakes in desalination plants around the world. On the other hand, if it is taken into account that 50–60% of the cost per cubic meter in reverse osmosis systems when operating with sea or brackish water is represented by the energy required and that photovoltaic solar energy can be used in three quarters parts of the Mexican territory, it is considered convenient to include this alternative in the projects and operation of desalination plants, such as the case of the “La Paz Aquifer”. Other sources of renewable energy as wind, geothermic or oceanic energy, and of clean energy as nuclear, can be considered for desalination purposes if they have some energy storage like pumped energy storage plants (PAEB for its acronym in Spanish).