There are four main types of solar energy technologies:

☛ Photovoltaic (PV) systems, which convert sunlight directly to electricity by means of PV cells made of semiconductor materials.

☛ Concentrating solar power (CSP) systems, which concentrate the sun's energy using reflective devices such as troughs or mirror panels to produce heat that is then used to generate electricity.

☛ Solar water heating systems, which contain a solar collector that faces the sun and either heats water directly or heats a "working fluid" that, in turn, is used to heat water.

☛ Transpired solar collectors, or "solar walls," which use solar energy to preheat ventilation air for a building.