Photovoltaics: Unlimited Electrical Energy from the Sun

The first practical solar cell was developed at Bell Laboratories in 1954. With the advent of the space program, photovoltaic cells made from semiconductor‐grade silicon quickly became the power source of choice for use on satellites. The systems were very reliable, and cost was of little concern. In the early 1970s, the disruption of oil supplies to the industrialized world led to serious consideration of photovoltaics as a terrestrial power source. This application focused research attention on improving performance, lowering costs and increasing reliability. These three issues remain important today even though researchers have made extraordinary progress over the years. This article details that progress.