ABSTRACT
To use solar energy, it is necessary to know how much is available in a particular location. Most countries now provide insolation maps which illustrate the amount of solar energy available over the year in a given location. Figures 10.4 and 10.5 show one for Africa and one for Europe, but they show different information. Figure 10.4 shows the annual average of each day’s sunshine falling on a horizontal surface taken over the years given. The key is in watt-hours per square metre. Figure 10.5 shows the figure in kilowatt-hours per square metre for optimally inclined south-facing PV modules. But it also includes an estimate of the amount of electricity that could be generated by a 1kW system with an efficiency of 75 per cent — although this might vary in practice.
