Solar-energy conversion is attractive because it is inexhaustible and nonpolluting. The main drawbacks are high cost and large area needed to collect enough solar power to make an impact on our daily total power demand. Nevertheless, a few solar power stations have been tried around the world to minimize the consumption of fossil fuels. Solar cells currently find unique applications in two particular areas. The first is for generating power for remote and rural areas. The extreme case is for space vehicles and satellites. Other examples are marine navigation lights, remote weather stations, telecommunication links, water pumps for irrigation, etc. Another area of applications is to replace low-power, high-cost batteries in consumer electronic products such as watches, calculators, exposure meters in photographic equipment, etc. It is also more convenient not having to change batteries periodically.
In applications where higher voltages are needed, solar cells can be connected in series. Similarly, they can be connected in parallel to supply larger currents. One approach to reduce the cost of the solar cell is to use a concentrator to focus light onto a smaller area. Actually the overall efficiency can increase with concentrated light intensity up to the equivalent of 100 suns. This is so because Jsc increases linearly with light intensity (before excessive heating), and the logarithmic increase of Voc also in turn improves the fill factor.