chapter  11
50 Pages


I’d put my money on the sun and solar energy. What a source of power! I hope we don’t have to wait until oil and coal run out before we tackle that. I wish I had more years left.

Thomas Edison

Photovoltaic conversion is the direct conversion of sunlight into electricity with no intervening heat engine. Photovoltaic devices are solid-state devices; therefore, they are rugged and simple in design and require very little maintenance. Perhaps the biggest advantage of solar photovoltaic devices is that they can be constructed as stand-alone systems to give outputs from microwatts to megawatts. That is why they have been used as the power sources for calculators, watches, water pumping, remote buildings, communications, satellites and space vehicles, and even megawatt-scale power plants. Photovoltaic panels can even be made to form components of building skin, such as roof shingles and wall panels. With such a vast array of applications, the demand for photovoltaics is increasing every year. According to the International Energy Agency, the market for photovoltaic solar cells has grown exponentially, increasing from 227 MW in 2000 to 20,500 MW in 2010 and 76,000 MW in 2016. Total world installed capacity is now just over 300,000 MW. The global market created $113 billion in revenue in 2015 [1]. An example of a photovoltaic residential rooftop system is shown in Figure 11.1.