Economic evaluation of desalination by small-scale autonomous solar-powered membrane distillation units

Solar-powered desalination is an attractive and viable method for the production of fresh water in remote arid areas. One of the most important factors determining desalination decisions is economics. This paper presents an economic assessment performed to estimate the expected water cost, which is the ultimate measure of the feasibility of the stand-alone system. Based on the calculations, the estimated cost of potable water produced by the compact unit is $15/m3, and $18/m3 for water produced by the large unit. Membrane lifetime and plant lifetime are key factors in determining the water production cost. The cost decreases with increasing the membrane and/or the plant lifetime.

Compact and Large autonomous solar powered membrane distillation systems were economically examined for the supply of potable water in the arid remote areas. Although the desalted water was produced using free energy, it is found that solar powered membrane distillation technology still expensive compared to other desalination processes. The expected potable water production cost was calculated to be $15/m3 and $18/m3 from the compact system and large system, respectively. It was found that increasing the reliability of the membrane distillation technology and plant lifetime could reduce the cost of the produced water significantly.