The Egyptians worshiped the sun god Ra, but in modern times the sun's power has mostly been taken for granted. That is probably a mistake. Each day, the earth receives a dose of solar energy equivalent to about 200,000 times the world's electrical-generating capacity. That makes solar power the ultimate renewable resource. But its potential remains largely untapped—chiefly because collecting and storing it remains expensive. The solar cell was developed by researchers at Bell Laboratories in 1954. Today, its far more efficient progeny are used in calculators, roof-top power systems, and spacecraft. Occasionally, they're grouped in fields to generate electrical power.

Related Links
Kyocera: "What is a Solar Cell?"

American Solar Energy Society: SolarGuide Factbase

DOE: National Renewable Energy Laboratory

National Center for Photovoltaics