Solar energy is radiant light and heat from the Sun that is harnessed using a range of technologies such as solar power to generate electricity, solar thermal energy, and solar architecture. It is an essential source of renewable energy, and its technologies are broadly characterized as either passive solar or active solar depending on how they capture and distribute solar energy or convert it into solar power. Active solar techniques include the use of photovoltaic systems, concentrated solar power, and solar water heating to harness the energy. Passive solar techniques include orienting a building to the Sun, selecting materials with favorable thermal mass or light-dispersing properties, and designing spaces that naturally circulate air.
The Sun produces electromagnetic radiation that can be harnessed as useful energy.
Solar water heaters facing the Sun to maximize gain
Parabolic dish produces steam for cooking, in Auroville, India.
Solar water disinfection in Indonesia
Solar thermal energy (STE) is a form of energy and a technology for harnessing solar energy to generate thermal energy for use in industry, and in the residential and commercial sectors. Solar thermal collectors are classified by the United States Energy Information Administration as low-, medium-, or high-temperature collectors. Low-temperature collectors are generally unglazed and used to heat swimming pools or to heat ventilation air. Medium-temperature collectors are also usually flat plates but are used for heating water or air for residential and commercial use.
Roof-mounted close-coupled thermosiphon solar water heater.
The first three units of Solnova in the foreground, with the two towers of the PS10 and PS20 solar power stations in the background.
Building integrated unglazed transpired solar air collector with grey walls and white canopy/collection ducts
Solar Evaporation Ponds in the Atacama Desert.