ABSTRACT
The cost of solar cells was immaterial compared with the cost of the entire satellite, its launch, and its maintenance in space. For terrestrial applications, low cost was the most important and efficiency was only secondary. Since about 1972, the development of solar cells to convert light to electricity split into two branches. One was for space applications, achieving high efficiency and durability in the space environment. In the 1990s, the World Bank established programs to provide electricity for the people in regions that could not be connected to the electric grid. Concentrating Thermal Solar Power technologies use mirrors to reflect and concentrate sunlight onto an absorber where it is converted to heat. A working fluid carries this heat into a conventional thermal power plant where the heat produces steam that drives one or more turbines, which then turn generators to produce electricity.
