In this post, you’ll learn about what is a solar power plant and different types of solar power plants.
Solar power plant
Among the various non-conventional sources of energy, the solar energy seems to hold out the greatest promise for mankind, as it is freely available, inexhaustible and non-polluting. Solar power is a form of energy harnessed from the power and heat of the Sun rays. It is renewable and therefore it is a “Green” source of energy.
“A solar power plant is based on converting sunlight into electricity, either directly using photovoltaic or indirectly using concentrated solar power. Concentrated solar power systems use lenses and tracking systems to focus a broad area of sunlight in a small beam “.
Solar power is the cleanest, most reliable form of renewable energy available and it can be used in several forms to help in power supply for residential premises and business.
Solar-powered photovoltaic panels convert sun rays into electricity by exciting electrons in silicon cells using photons by the light from the sun.
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Meaning of Solar Power
Solar energy is the use of sun energy directly as thermal energy (heat) or through the use of photovoltaic cells in solar and transparent photovoltaic glass to generate electricity.
Types of Solar Power Plant
Following are the two types of large scale solar power plants:
- Photovoltaic power plants
- Concentrated solar power plants (CSP) or Solar thermal power plant.
1. Solar Photovoltaic Power Plants
The process of converting light (photons) into electricity (voltage) is known as a solar photovoltaic (PV) effect. Photovoltaic solar energy cells convert sunlight into solar energy (electricity).
They use a thin layer of semiconducting material, usually silicon, or silicon alloys encased between a sheet of glass and a polymer resin. When exposed to sunlight, the particles of solar energy known as photons strike the surface of a photovoltaic cell, the semiconducting material exhibit a property known as the photovoltaic effect.
This causes them to absorb the photons and release electrons, an electron in the semiconducting material become energised. These electrons are then flowing through the material generating direct current. These are also used for residential needs on a smaller scale.
2. Concentrated Solar Power Plants or Solar Thermal Power Plant
Concentrated Solar Power Plants (CSP) do not convert sunlight directly into electricity. Instead, they use mirrors, lenses and tracking systems to focus a large area of sunlight into a small beam. It is then used as the heated source, similar to a conventional power station.
There are a few types of CSP power station but all use the same principle of heating the working fluid by direct sunlight.
The concentrated solar power plant or solar thermal power plant generates heat and electricity by concentrating the sun’s energy. That, in turn, builds steam that helps to fed a turbine and generator to produce electricity.
There are three types:
- Parabolic troughs
- Solar power tower
- Solar pond
1. Parabolic Troughs
This is the common type of solar thermal plant. A “solar field” contains several parallel rows of solar parabolic trough collectors. They use parabolically shaped reflectors to focus the sun at 30 to 100 times its normal intensity.
The method is used to heat a special type of fluid, which is then collected at a central location to generate high pressure, superheated steam.
2. Solar Power Tower
Solar power tower system uses hundreds to thousands of flat sun-tracking mirrors known as heliostats to reflect and concentrate the sun’s energy onto a central receiver tower. Energy can be concentrated up to 1500 times the energy coming from the Sun.
The concentrated solar energy is used to heat the air in the tower up to 700°C (1,300°f). The heat is captured in a boiler and utilised to generate electricity with the help of a steam turbine.
3. Solar Pond
It is a pool of saltwater that collects and stores solar thermal energy. It uses salinity-gradient technology. The bottom layer of the pond is hot up to 85°C and works as a transparent insulator, allowing sunlight to be trapped from which heat may be removed or stored for late use.
General Terms of Solar Energy
Following are some general terms which are commonly used with solar energy:
1. Solar Constant
The solar constant is the energy from the Sun, per unit time, received on a unit area of the surface perpendicular to the radiation, in space at the earth’s mean distance the Sun.
2. Beam Radiation
The solar radiation received from the Sun without a change of direction is beam radiation.
3. Diffuse Radiation
It is solar radiation received from the sun after its direction has been changed by the reflection and scattering by the atmosphere.
4. Air Mass
It is the path length of the radiation through the atmosphere, considering the vertical path at sea level as unity.
5. Zenith Angle
Zenith is the angle between the beam from the Sun and the vertical.
6. Solar Attitude
It is an angle between the beam from the Sun and horizontal i.e. (90° Zenith angle).
7. Solar or Short Wave Radiation
It is the radiation originating from the Sun, at a source temperature of about 6000°K and the wavelength range of 0.3 to 3.0 μm.
8. Long Wave Radiation
Radiation arising from sources at temperatures near normal ambient temperatures and thus exceeding 3 μm in all wavelengths.
9. Declination
Declination is the angular position of the Sun in the solar noon with respect to the plane of the equator (north positive).
That’s It
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