Electric connections

Electric power. What is it?

Electric power. What is it?

We define electrical energy as the form of energy that results from the existence of a potential difference between two points. When these two points are brought into contact by an electric conductor we obtain an electric current.

Physical aspects of electrical energy

From the physical point of view, electrical energy is negative electric charges (electrons) that move through the electric conductor, usually metallic, due to the potential difference between its ends. The reason metal conductors are usually used is because they have more free electrons.

Electric charges moving through the conductor are part of the atoms of the conductor's own substances.

In physics the potential for electrical energy is also called electrostatic potential energy.

At a somewhat more technical level of physics, the electric potential is the potential energy of the electrostatic field. It is the energy that has an electric charge distribution that is linked to the force exerted by the generated field of the same distribution. Along with magnetic energy, the potential of electric energy is the energy of the electromagnetic field.

Electrostatic potential energy can be defined as the work done to create a charge distribution from an initial configuration in which each of the components of the distribution does not interact with the other. The electrostatic potential energy can also be defined from the electrostatic field generated from the same distribution, and in this case its expression is independent of the field source.

It is a magintud that can be negative or positive, depending on if the work done so that they are in the adopted configuration is positive or negative. Two charges that interact in the same sign have positive energy, since the work done to bring them closer must overcome their repulsion. By the same token, two opposing charges have negative energy.

Electric power generation

Electrical energy can hardly be found freely in nature in a way that can be exploited. It can be observed in thunderstorms but the difficulty of storing and controlling such amount of energy makes them practically unusable.

There are several ways to generate electricity that we can classify in renewable or non-renewable. The forms of generating renewable electric energy are those in which no fuel is used or the fuel is inexhaustible (solar energy, wind energy, hydroelectric energy, geothermal energy, etc.). On the other hand, the forms of generating non-renewable electrical energy require a fuel that, however abundant, tends to be exhausted, such as nuclear energy, thermal energy (coal, oil, gas & hellip; etc.)

Use of electricity

Trains running by electric power Electric energy can be transformed into many other types of energy such as mechanical energy (electric motors, machines ...), thermal energy (heaters, stoves ...) or light energy. The great advantage that electric power gives us is the ease of transporting it.

The use of electricity is very widespread in modern society and current through the connection to the electricity grid or through batteries or accumulators: just think of the use of lighting buildings (public and private) and roads, In the power of apparatus and equipment, as well as in industrial production processes or in electric machines, such as electric motors.

Thus, the discovery of electric energy has represented a very strong technological, economic and social revolution. Its use has caused a strong and irreversible need due to its benefits compared to mechanical energy produced by the thermal engines (combustion engines). Among them was the fact of being able to be transported at a distance, the low operating noise of electrical equipment, the absence of exhaust fumes at the place of use and the smallest footprint of an electric machine.

Among the disadvantages is the fact that it is not a primary source. The use of electric power implies the need for a conversion infrastructure that inevitably introduces a loss of efficiency in the conversion process and upstream in transport along the power lines.

Electric power plants

Electricity, except for the lightning's atmospheric electricity and the Earth's weakly negative potential, is not a primary energy source of the earth so it has to be produced by transforming a source of energy primary. In this way, electrical energy is considered as a secondary energy source. In the process of transformation, the yield always less than 100%, occurs within the power plants.


In all electric power plants, except for photovoltaic solar energy, three elements are needed to produce electricity:

  • Turbine
  • Alternator
  • Transformer

Another important element for producing electricity is water in liquid form (as in hydroelectric plants) or in the form of high pressure steam (in thermal plants, geothermal power plants, nuclear fission and solar thermal plants) , In order to rotate the turbines to produce alternating current more consistently by the alternator.

The use of water presents the following problems arising from the need to heat it:

  • Water availability.
  • Thermal contamination of water, if not recovered, is dispersed into the atmosphere in the form of water vapor or fed back into lakes, rivers and the sea.

In the case of wind plants, no water is needed, since the turbines are driven by the force of the wind.

Electricity distribution and supply

Once production of electricity is complete, there is a need to transport it on a large scale. The large-scale transportation and distribution of electricity produced by the plants to the end users takes place through the transmission network and the distribution network.

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Last review: November 25, 2016