Page - 183 - in Clean Water Using Solar and Wind - Outside the Power Grid

Glossary 183 Scaling: precipitation of solid substances on the membrane in nano- and reverse osmosis filtration. Silicon: the basic material used to make solar cells. It is the second most abundant element in the earth’s crust, after oxygen. Silicon is a metal and, therefore, its atoms are organised into a crystalline structure. Solar home system (SHS): a stand-alone (not connected to the electricity grid) system composed of a relatively low-power photovoltaic module, a battery and sometimes a charge controller, which can power small electric devices and provide modest amounts of electricity to homes for lighting and radios. State of charge (SoC): the present battery capacity as a percentage of maximum capacity. SoC can be calculated by integrating the current over time. Surface water: water pumped from sources open to the atmosphere, such as rivers, lakes and reservoirs. System cost: this includes all components of a renewable energy system other than the photovoltaic panels or the wind turbine. This contains wiring, switches, a mounting system, one or many inverters, a battery bank and battery charger. Other soft costs include: financing, mechanical installation, electrical installation, system design, customer acquisition, permitting, inspection/certification, connection, operation and maintenance. Variable renewable energy: see Intermittent electricity. Water consumption: the volume withdrawn that is not returned to the source (i.e. it is evaporated or transported to another location) and so by definition is no longer available for other uses (see Water withdrawal). Water footprint: the amount of fresh water utilised, for example for energy production (such as litres/kWh). Water stress: defined as when renewable annual fresh-water supplies fall below 1,700 m3 per person and year; water scarcity (limitation to economic development and human health and well-being) is below Downloaded from https://iwaponline.com/ebooks/book-pdf/520710/wio9781780409443.pdf by IWA Publishing user