There are various technologies associated with solar power, but all of them come under two major groups. The solar thermal technology--which includes passive solar heating and solar concentrator power systems-- use the sun to generate heat. Solar power technology, the second group, converts solar radiation into electricity through photovoltaics--a technology capable of producing electricity when exposed to light.

Group 1: Solar Power Through Solar Thermal Technology

Solar thermal technologies vary from small—in which a parabolic disk cooks food and boils water--to large, in which centralized solar power plants use many acres of mirrors to collect the sun's power, focus it and heat water to steam that will power generators. Solar concentrator power systems use mirrors and lenses to concentrate sunlight onto a receiver, which converts the sunlight into heat. This heat is used to heat fluid, which is led through pipes to a steam generator, where it is converted into electricity.

Power plants with a capacity of 10 megawatts can power 10,000 households, and future power plants with capacities ranging from 30 to 200 megawatts are possible.

Flat-plate solar collectors are large, flat boxes dark-colored metal plates inside that absorb heat. This system is great for providing heated water for household use by passing water through pipes that are heated by the heat absorbed in these plates. Passive solar heating like this uses the sun's thermal power to heat the buildings. The south facing windows in the northern hemisphere invite the sun's warm rays in, helped by building materials that absorb the sun's thermal energy.

Another benefit of solar thermal technology, which isn't very apparent, and even seems oxymoronic, is its ability to cool buildings. This is done with absorption-cooling devices and desiccant cooling systems.

Group 2: Solar Power Through Photovoltaics

Photovoltaics is another way of collecting the sun's energy. Solar cells made of semi-conductors convert the energy in sunlight into electricity. Sunlight, which is a stream of energy particles known as photons, hits the semi-conductors and transfers its energy into them. These photons generate electricity as they hit the silicon atoms in the solar cells.

Mirrored dishes and fresnel lenses, which consist of concentric rings of segmental lenses, and are used to help concentrate the sunlight onto a small area of photovoltaic cells. Concentrated photons cause a photoelectric effect as they hit one of the pairs of negatively charged plates and liberate the electrons. These liberated electrons are attracted to the other negatively charged plate. This flowing of electrons from one plate to the other is an electric current.