Solar power harnesses the sun's heat and light emissions. It is the power we get from converting the sun's energy. The energy of the sun is abundant, clean, and environmentally friendly. Every day, we receive more energy from the sun than the entire world could use in 27 years! Solar power is highly renewable, as the energy from the sun is estimated to last another 4.5 billion years.
The basic difference between generation of solar power and the conventional power is:
* Solar power doesn't need large, polluting power stations
* Solar power can be generated at home and in industries
* Once installed, there is no further need of any raw materials to generate solar power
Converting the Sun's Energy
There are many different ways of converting the sun's energy, in the form of light, into electricity. Photovoltaic cells, more commonly known as solar cells, are made of semi-conductors. These energy converters convert the energy in sunlight into electricity. Sunlight, which is a stream of energy particles--photons--falls on the semi-conductors or the conductors and transfers its energy to them. The photons transfer their energy as they hit the silicon atoms in the solar cells, thereby releasing the electrons from their orbit around the nucleus, generating electricity.
To help concentrate the sunlight on a small area of photovoltaic cells, Fresnel lenses, mirrors, and mirrored dishes are used as concentrators. A Fresnel lens consists of concentric rings of segmental lenses with a short focal length. Multiple solar cells are combined to make a solar panel. For protection of these solar cells, glass, with an anti-reflective coating, is used as a cover. Solar panels usually produce 12 or 24 volts of DC power.
Boiling Fluids - Mirrors or reflective surfaces are used to concentrate the sun's energy onto a fluid reservoir. This leads to steam generation by boiling the fluid, which in turn spins a turbine to generate electricity. Using a turbine to generate electricity is similar to the conventional way of power generation, except that solar energy is used in place of non-renewable fossil fuels. Either DC or AC electric power can be generated using turbines.
Heat Engine - The heat engine, the most common one being a Stirling engine, has a gas- enclosed compartment. Through mirrors or reflective surfaces, the sunlight is concentrated on the engine, which heats the gas. This causes a piston to move, which runs the generator. The gas gets cooled and returns to go through the heating cycle again. These heat engines are silent. Depending on the generator, they can produce either DC or AC current.
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