Page 918 - Basic Electrical Engineering

of electrons released from silicon depends upon the intensity of light falling
on it. One PV cell or Solar cell produces about 1.5 W of electricity when
exposed to bright sun. Individual solar cells are connected together to form a

panel or module capable of producing upto about 100 W of electric power. A
number of such panels are then connected in series and parallel to produce a

considerable amount of electricity. Common applications of PV systems are
found in street lighting and indoor lighting, particularly in far flung and hilly

areas where conventional electric supply may be expensive because of its
long route.

Commercial solar cells producing electricity have an efficiency of about 15
per cent only. Low-efficiency system means larger arrays would be required
for electricity generation, and hence would cost more. However, research is

being conducted to improve the efficiency of solar cells so as to make the
system economically viable. Government of India provides subsidy to

manufacturers and users of solar appliances to encourage their use.

Figure 13.4 Wind turbine–generator

13.7.2 Wind Energy to Produce Electricity