Solar energy (solar energy), refers to the sun's thermal radiation (see the three ways of thermal energy transmission: radiation), the main performance is often said that the sun's rays. In the modern general use for power generation or to provide energy for water heaters. Since the birth of life on earth, mainly to the sun to provide the heat radiation can survive, and since ancient times humans also know how to sun dry objects, and as a method of making food, such as salt and salted fish and so on. In the case of fossil fuels declining, solar energy has become an important part of human energy use, and continue to develop. The use of solar energy with light and heat conversion and photoelectric conversion in two ways, solar power is a new renewable energy. Broadly speaking, solar energy also includes the Earth's wind energy, chemical energy, water and so on.