Solar thermal energy (STE) is a technology for harnessing solar energy for thermal energy (heat). Solar thermal collectors are defined by the USA Energy Information Administration as low-, medium-, or high-temperature collectors.
- Low temperature collectors are flat plates generally used to heat swimming pools.
- Medium-temperature collectors are also usually flat plates but are used for creating hot water for residential and commercial use.
- High temperature collectors concentrate sunlight using mirrors or lenses and are generally used for electric power production.
STE is different from photovoltaics, which convert solar energy directly into electricity.