Physics trivia

Solar plants

Solar plants use the energy emitted by the Sun to produce electricity in a clean and sustainable way. Read this text and learn how solar plants work.

Solar panels are used in photovoltaic plants to produce electricity.
Solar power plants transform the radiation energy emitted by the Sun into electrical energy. There are two types of solar plants: photovoltaic plants and solar thermal plants Although both use the same source, the energy conversion processes performed by them are different.

What is a solar plant?

Solar plants are complex arrangements of equipment intended for the transformation of energy transmitted by solar radiation into electrical energy. According to the transformation process undergone by solar energy, the type of solar plant can be defined. Power plants that use the heat emitted by the Sun are called solar thermoelectric plants. The plants that use the other frequencies of sunlight, generating electricity through solar panels, are called photovoltaic plants .

→ Thermosolar plants

Solar thermal plants focus sunlight on a large reservoir of water through an arrangement of several concave mirrors . These mirrors are arranged so that their focuses are aligned, causing all light incident on them to be reflected on a single point.

Due to the concentration of light rays, the reservoir, which holds a large amount of water vapor confined, reaches very high pressures and temperatures. When the valves that confine the contents of the reservoir are loosened, this steam is released with sufficient velocity to drive large turbines, similar to those used in hydroelectric power plants . In this way, electric currents are generated by the process of electromagnetic induction .

The association of several concave mirrors allows the heating of water in solar thermal plants.

→ Photovoltaic plants

Photovoltaic plants generate electricity through the photoelectric effect , specifically the photovoltaic effect . The photoelectric effect arises when a material is exposed to light radiation , ejecting its electrons out of the material. The photovoltaic effect , used in photovoltaic plants, is a similar phenomenon, but more attenuated than the photoelectric effect, as light causes the appearance of a potential difference in the material without ripping off its electrons.

Photovoltaic cells are the basic units of solar panels.

Photovoltaic plants have a large number of solar panels, composed of photovoltaic cells. These cells are formed by semiconductor materials, such as silicon, capable of transforming solar energy into electric current.

Both photovoltaic and solar thermal plants use the energy of radiation emitted by the Sun. In addition to this virtually infinite and renewable resource, some materials are used for the construction of photovoltaic cells and reflecting mirrors, silicon being the most important of them. Fortunately, silicon is the most abundant material on Earth (27% of its composition).

What makes the manufacture of these fundamental elements of solar plants expensive are the techniques used and the purity of the elements used in their construction.

Advantages and disadvantages of solar plants

Benefits Disadvantages
They do not emit polluting gases. Cloudy climates, rain and snow can have a major impact on power generation by these plants.
They have a low maintenance cost. Locations far from the equator receive less light and, therefore, are less efficient in capturing solar energy.
As there is a high incidence of light in Brazil, they can be installed in several places. Proportionally, they produce less energy than thermoelectric plants, for example.
They usually take up little space.  

Solar plants in the world

Currently, China is the country with the largest installed capacity for solar energy generation: 42,800 MW. About 25% of all solar voltaic energy in the world is produced in this country. The second country in solar energy generation is Japan, with an installed capacity of 8600 MW . Then comes Germany, which captures about 13% of all solar energy offered globally.

Below, we have a list that presents the largest solar plants in power generation capacity in the world:

  • Solar Star (USA): can generate up to 579 MW.
  • Topaz solar farm (USA): at its peak production, it generates 550 MW of power.
  • Desert sunlight solar farm (USA): 550 MW peak power.
  • Longyangxia (China): capable of generating up to 480 MW of power.
  • Benban Complex (Egypt): In 2019, it will become the largest solar plant in the world, with an installed capacity of 1.8 GW .

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