Page - 123 - in Clean Water Using Solar and Wind - Outside the Power Grid

Handling variable production 123 10.2 STORAGE OF ENERGY A solar PV system is limited to working only in daylight unless it is integrated with an energy storage system. A solar thermal system with a medium for thermal storage can operate through the day. Heat can be stored during the day and excess daytime heat can potentially be stored, as shown in Chapter 6. Often solar PV and wind can complement each other to provide a more reliable power source (Weiner et  al., 2001). Meteorological data will decide whether the accumulated wind and solar energy production can satisfy the power demand. The combination of solar, wind and battery storage is often too costly for poor areas that may be satisfied, at least primarily, with less ambitious energy supply. 10.2.1 Storage requirements in low-income versus high-income countries The priorities concerning variable energy sources appear to be quite different in high-income and in low-income regions. In the former case power availability around the clock is emphasised, even if it means a higher cost for control and storage. For the user in a low-income country there is a higher acceptance that power is not available around the clock, particularly for those people who previously had no electric power. 10.2.2 Storage technologies There is no “one-size-fits-all” solution to storage need. There are several different technologies available and the type of need as well as economy will determine the kind of technology to be used. Different technologies are suitable depending on the timescale: • Timescale of minutes to less than an hour: The purpose of the storage is to keep the power delivery from solar and wind smooth. Also, short variations in the consumption can be compensated for. In any intermittent production the need for storage capacity must be well thought out. Downloaded from https://iwaponline.com/ebooks/book-pdf/520710/wio9781780409443.pdf by IWA Publishing user