applied sciences  
Is Small Scale Desalination Coupled with Renewable Energy a Cost-Effective Solution? [PERSON] and [PERSON]  
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create adverse economic and environmental impacts such as the minimization of water resources and the increase of greenhouse gas (GHG) emissions. One of the solutions deployed in the last decades for island and coastal areas overcoming the disadvantages of water transfers has been desalination. Desalination is commonly defined as the process of removing dissolved salts from saline or brackish water to make it suitable for human use and consumption, i.e., domestic, agricultural, and industrial purposes. It is considered as an important alternative for the supply of fresh water, especially in water scarce regions. Desalination processes take a saline water source and put in energy to produce two separate streams, a stream of fresh water and a stream of brine (concentrated salt water) (Figure 1). It is desirable that a desalination technology be highly efficient, which means to use a minimal amount of energy and produce a large volume of fresh water and a small volume of highly concentrated brine. The desalination of seawater and brackish groundwater is commercially available and still a fast advancing technology, which already provides fresh water to many towns and cities worldwide through large-scale applications as well as from well-established very small-scale applications for ships, yachts, etc. Despite its high cost, desalinated water is also used for land irrigation (agriculture) today [5,6]. The desalination technologies may be categorized as thermal desalination (distillation) processes, membrane processes, and charge based desalination technologies (ion exchange processes). Thermal methods are based on the water phase change. Heat is used to evaporate the salty water (leaving salt behind) and then the water vapour is condensed to obtain fresh water. Membrane desalination processes use differences in osmotic potentials (pressures) across a semi-permeable polymer membrane to physically separate salt from water. Charge-based separation techniques are based on the fact that salt consists of charged ions, which can be withdrawn from water by applying an electric potential. Thermal technologies are highly effective at large capacities (several thousands of m\({}^{3}\)/d) while charge-based separation technologies are best suited for smaller operations (few hundreds of m\({}^{3}\)/d) and brackish water. Membrane desalination methods are the most popular, have been optimized and commercialized for a broad range of capacities, from very large-scale industrial use (hundreds of thousands of m\({}^{3}\)/d) to very small-scale (less than 1 m\({}^{3}\)/d) in-home applications [7]. Reverse osmosis (RO) is a commonly used water purification technology that employs a semipermeable membrane to remove ions, molecules, and larger particles from drinking water. In RO, a pressure is applied, higher than the osmotic one that is driven by chemical potential differences of the solvent.