Page - 115 - in Clean Water Using Solar and Wind - Outside the Power Grid

Wind 115 power parks have a capacity of around 50% and will probably increase to 55–60% once 10 MW turbines have been installed (Svensson, 2018). It is apparent that the variability of wind power generation can be minimised if many wind turbines are connected in a large grid. When generation is connected over a large geographical area the local variations in wind can compensate for each other. As a result, the intermittency of wind generation can be reduced significantly. This means that off-grid wind turbines are more sensitive to changes in wind and local stand-alone wind turbines will have a relatively higher variability than a wind farm. Wind energy technology is a mature technology and the systems operate at very high rates of availability. Availability of the turbine is the proportion of time the turbine is ready for operation. Onshore turbines typically have availabilities of 98%, while offshore turbine availabilities are slightly lower (95–98%). Today’s turbines already extract nearly 50% of the energy conveyed in the wind. Solar PV and wind can sometimes compensate for each other and create a less variable power production if they are connected. The wind may blow on a cloudy day or during the night, thus compensating for lack of solar power. 9.3 FURTHER READING WEC (2016), Chapter 10 provides an easy-reading introduction to wind power. World Bank (2017) presents detailed information about global access to wind power. IRENA (2015c) reports on technology quality for small wind turbines. A key issue is to limit the cost in developing markets but still maintain the reliability and quality of the systems. For the interested reader the textbook by Manwell et  al. (2011) gives an excellent introduction to wind power systems. The capacity factor for onshore wind power is of the order 25% while offshore can reach 50%. Downloaded from https://iwaponline.com/ebooks/book-pdf/520710/wio9781780409443.pdf by IWA Publishing user