Page - 177 - in Clean Water Using Solar and Wind - Outside the Power Grid

Outlook to 2030 and further 177 15.2 DESALINATION RESEARCH AND DEVELOPMENT It is an important research topic to adapt desalination technology to the variability of renewable energy sources. The intermittent power production of solar PV implies that solar-powered desalination membranes will undoubtedly operate outside their optimum operation window. Therefore, it is essential to investigate the long-term reliability of variable and intermittent operation (non-stable pressure and flow rate) on membrane reliability. This includes salt passage at the ion level, fouling (colloidal, biological and organic) and scaling (mineral and salt precipitates) of membranes (Lienhard et  al., 2016; Zaragoza, 2018). A lot of research is ongoing into finding new types of membranes for RO. Graphene is one of the strongest materials known. A graphene membrane is only one atom layer thick and has much higher permeability than today’s membranes. This means that less pressure and electric energy will be required for desalination. Other challenges include the overall design and optimisation of the components in the integrated system. Control and management aspects should be taken into consideration at the design stage so that the energy flow in the system can be assured for all possible operational conditions. Another challenge is related to small-scale technology. Small-scale operations struggle to be cost-competitive with utility-scale water operations. 15.3 SOFT ISSUES Supplying clean water using renewable energy includes many “soft” issues, as described in the preceding chapters. Integration between energy supply and water operations should be better understood. It is essential that energy production is adapted to the needs from the loads such as the pumps, desalination units and water remediation units. 15.3.1 Education and training Off-grid energy generation and water operations are small-scale and decentralised. There are lessons to learn from experiences so far, Downloaded from https://iwaponline.com/ebooks/book-pdf/520710/wio9781780409443.pdf by IWA Publishing user