Panels photovoltaic solar energy

Photovoltaics

Photovoltaics

Solar photovoltaic energy consists in the direct transformation of solar radiation into electrical energy. This type of energy is often referred to directly as photovoltaic energy.

This transformation into electrical energy is achieved by taking advantage of the properties of semiconductor materials through photovoltaic cells. The base material for the manufacture of photovoltaic panels is usually silicon. When sunlight (photons) hits one of the faces of the solar cell, it generates an electric current. This generated electricity can be used as an energy source.

Manufacturing photovoltaic cells is a costly process, both economically and in time. The silica with which the photovoltaic cells are manufactured is a very abundant material on Earth. However, the processing of silicon is laborious and complicated. By means of very complicated processes, silicon ingots are made. Subsequently, wafers ( photovoltaic cells) will be cut from these silicon ingots.

Another source for obtaining silicon is the recycling of the electronics industry.

Other higher performance materials are currently being prepared.

It is important that all the cells that make up a solar photovoltaic panel have the same characteristics. After the manufacture of photovoltaic cells, a classification and selection process must be followed.

Efficiency of photovoltaic energy

Photovoltaic panels - photovoltaic solar energy

Depending on the construction, photovoltaic modules can produce electricity from a specific range of light frequencies, but in general it can not cover the entire solar range (in particular, ultraviolet, infrared and low or diffuse light). Therefore, much of the energy of incident sunlight is not used by solar panels, which could give much higher efficiencies if illuminated with monochromatic light.

Therefore, another design concept is to divide the light into different wavelengths and direct the beams in different cells tuned to these ranges. This has been projected to be able to increase efficiency by 50%. Scientists from Spectrolab, a subsidiary of Boeing, reported the development of multi-union solar cells with an efficiency of more than 40%, a new world record for photovoltaic solar cells. Spectrolab scientists also predict that concentrating solar cells could reach efficiencies of more than 45% or even 50% in the future, with theoretical efficiencies of about 58% in cells with more than three junctions.

Currently, the best rate of conversion of sunlight into photovoltaic energy in new commercial products achieves an efficiency of the solar module of around 21.5%.

Applications of photovoltaic solar energy

Utilization of photovoltaic solar energy for public lighting

The main application of a photovoltaic solar energy installation is the production of electrical energy from solar radiation.

Energy production can be large-scale for general or small-scale consumption for consumption in small dwellings, mountain shelters or isolated sites.

Mainly there are two types of photovoltaic installations:

  • Photovoltaic installations for grid connection, where the energy produced is used entirely for sale to the distribution network.
  • Isolated photovoltaic network installations, which are used for self-consumption, be it an isolated dwelling, a telecommunication relay station, water pumping for irrigation, etc.

Within the applications of photovoltaic energy not connected to the grid we find in many areas of daily life. Photovoltaic energy is used in small devices such as calculators, as for public lighting in certain areas, to power electric motors and even cars and airplanes have been developed that work exclusively by taking advantage of solar radiation as an energy source.

History of photovoltaic energy

The photovoltaic energy generated with the photovoltaic effect was recognized for the first time in 1839 by the French physicist Becquerel. However, it was not until 1883 that the first solar cell was built by Charles Fritts with an efficiency of 1%. During the first half of the 20th century there were several improvements to increase its efficiency.

In 1946, Russel Ohl patented the modern union between the semiconductor materials that is currently used. But the most important technological advance came in 1954 when Bell Laboratories, experimenting with semiconductors, developed the first silicon photovoltaic cell, with a yield of 4.5%.

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References

  1. Roper, L. David. World Photovoltaic Energy
  2. REN21 (2009). Renewables Global Status Report: 2009 Update
  3. Swanson, R. M. (2009). Photovoltaics Power Up
  4. «Photovoltaic Effect»  Mrsolar.com
  5. «The photovoltaic effect»  Encyclobeamia.solarbotics.net.
  6. «La fotovoltaica ya se codea en costes con la nuclear». El periódico de la energía. 

Last review: May 24, 2018