Seite - 122 - in Clean Water Using Solar and Wind - Outside the Power Grid

122 Clean Water Using Solar and Wind: Outside the Power Grid 10.1.3 Intermittent desalination Intermittent use of a desalination plant to meet baseload water demand requires oversizing the plant relative to what would be needed under steady operation. Another difficulty is that the long-term reliability and the operational life of membranes are affected by intermittent operation and variable pressure (Lienhard et  al., 2016). Intermittent power supply for desalination causes damage to the equipment. The membranes in a reverse osmosis plant are the most sensitive parts of the system. They are designed to have a constant pressure so they will last a long time, but with variable pressure their usual operational life of eight years (with a well operated plant) may reduce to two years. Research is needed to study and further understand the phenomena taking place within RO membranes operating under variable pressure and intermittent conditions. Another important problem observed in transient operation of desalination systems is the increased risk of membrane scaling, bio, organic and mineral fouling, collectively known as fouling. Increased fouling also necessitates greater cleaning activities and the membranes may need to be replaced earlier (Lienhard et  al., 2016, Chapter 2). A desalination plant that requires a certain production around the clock will need power for 24 hours, but the solar PV is available for only around eight hours/day. Thus, the power of the solar PV system must be at least three times the size of a power plant that operates around the clock. Intermittent power supply for desalination is shortening the operating life of the equipment. To produce a certain amount of energy, a solar PV system operating eight hours per day will require a power rating three times higher than a system operating around the clock. Downloaded from https://iwaponline.com/ebooks/book-pdf/520710/wio9781780409443.pdf by IWA Publishing user