Solar Technologies — The Basics

There are three major applications for solar power. They are passive solar heating, solar thermal electricity generation and photovoltaics. The first two involve using the sun’s heat to make a fluid — usually water — hot, and if you make it very hot you can use the steam to run a turbine to generate electricity, exactly as in fossil fuel-fired power plants. They are included for completeness and because solar heat can, in the right place, significantly contribute to energy supply. The third application, photovoltaics, is the main focus of this book. It is a technology that has no moving parts and requires no material inputs once it is installed, and generates electricity directly. It is also the one that has made great progress technically and economically in the last few decades, and looks set to explode further.