What is electricity? Types and applications

Electricity is a form of energy that arises from the difference in electric potential between two specific points, achieved by linking them through an electrical conductor. This contact generates an electric current, which involves the transfer of negative electrical charges (electrons) through a conductive material, usually one or more metals. This current flows from the point where it is generated and/or stored to the point of consumption. The electricity generated is frequently transformed into other forms of energy, such as light, mechanical or thermal energy.

The generation of electrical energy encompasses all the processes that make it possible to convert primary energy sources, present in the natural environment, into usable electrical energy. The exponential increase in energy consumption experienced in recent decades has led to a significant increase in the production of electricity, a trend that is expected to continue growing in the coming years. In this regard, the International Energy Agency (IEA)  projects a 60% increase in energy consumption worldwide over the next three decades.

Faced with a growing demand for energy and in a world that is increasingly concerned about the environmental and climatic effects associated with CO₂ emissions, the debate around how electricity is generated has become very significant, especially with regard to energy produced from renewable sources.

Types of electricity based on their form

If we talk about the types of electrical energy, there are different classifications to organize them according to different criteria. If we differentiate between energies by the forms they take, we can distinguish three types: 

Static energy is the result of the accumulation of electrical charge in a specific area, usually on the surface of objects. This phenomenon occurs when electrons move from one surface to another through contact, especially in insulating materials. When two insulating surfaces come into contact, they can accumulate an electric charge, resulting in one object having a positive charge (from losing electrons) and another with a negative charge (from gaining electrons).

Its applications include a number of practical uses, such as xerography for laser printing, where a photosensitive drum is charged and the toner is attracted. It is also used in air filters to improve filtration efficiency by attracting electrically charged particles. In the application of automotive paints, static electricity ensures an even distribution of paint particles, achieving a high-quality finish.

Then there is dynamic energy. Electrons release a substance, usually inside an electrical generator. This process may involve different sources of energy, these include burning fossil fuels, hydro-electric power and wind power. The release of electrons creates a flow of electric charge. There are two types of dynamic energy: Alternating current and direct current. 

Dynamic electricity has a number of applications including electrical circuits, and these are essential for the operation of appliances, automotive systems and other devices. Electricity transmission systems which use alternating current to transmit electricity efficiently over long distances from the power stations.

Finally, electromagnetic energy manifests itself through waves of electric and magnetic fields that are propagated in space and move at the speed of light. The area where these waves exist is called the electromagnetic field. Although the sun is the main natural source of electromagnetic energy, human activities also generate significant amounts of artificial electromagnetic radiation in our environment.

Some of the environments where we find electromagnetic energy are: Medium and high voltage lines, electricity transformers and some domestic appliances such as refrigerators, hair dryers, etc. Electromagnetic energy is also present in electronic devices such as computers, alarm systems, radios, televisions, mobile and cordless phones, microwaves, Wi-Fi and Bluetooth.

Methods for generating electricity

The way in which energy is acquired is not the only method that exists to classify the different types of electrical energy. There are different methods of generating electricity for consumption, which also enable us to distinguish between them and that can be divided into two large groups: 

Renewable electricity generation:  

Renewable energies come from natural sources, such as wind power, hydropower, and solar heat. They are inexhaustible and environmentally friendly sources. In Spain, 46% of the energy used is renewable. Some examples of renewable sources include:

• Wind energy: It is generated through wind turbines in wind farms, which transform the kinetic energy of the wind into electricity. Although it is inexhaustible, its stability is subject to atmospheric conditions.

• Solar Energy: It is obtained when sunlight hits solar panels, generating electrons and creating a flow of electricity. Smart solar panels adjust their orientation to follow the sun's path, increasing efficiency. 

• Hydropower: It uses the force of moving water to generate electricity using hydro turbines. Although it is a renewable, in-demand and sustainable source, it requires a larger infrastructure due to the construction of dikes or dams.

   

Non-renewable electricity generation: 

Non-renewable energy sources are characterized by using limited natural resources to generate electricity. These sources are often less accessible, as they are concentrated in specific locations on the planet. They are classified into two main groups according to their method of extraction:

• Fossil fuels: This type of energy is obtained by burning resources such as oil, coal or natural gas. Although the current trend points towards a decrease in dependence on these fossil fuels to advance decarbonisation, they still play an important role in the energy matrix.

• Nuclear fuels: Nuclear fission is the most commonly used process to generate nuclear energy, releasing a large amount of energy. However, this process generates radioactive nuclear waste and this is a significant, controversial issue.

   

Unusual facts about electricity

There are many species of animals that use electrical energy to hunt. Platypuses, echidnas and bumblebees represent extraordinary examples of terrestrial animals with the ability to perceive electric fields, using them for prey detection or communication. 

The first city in Spain to have public lighting powered by electricity was Girona in 1886. During a session held on 4 December 1885, the Girona City Council decided to implement a certain number of incandescent lamps. Instead of opting for the installation of direct current machines, it was decided to adopt alternating current dynamos. 

Electricity is present in our body. Electricity is critical to the heartbeat as it drives the contraction of the muscles in this organ. This electrical interaction can be clearly visualised by an ECG machine, which displays a line with regular peaks on the screen.

As you can see, electricity has become fundamentally integrated into our daily lives, giving us access electricity in our homes 24 hours a day. It facilitates a number of everyday activities, from cooking and using electronic devices to enjoying entertainment. In this context, global energy consumption is constant and growing. Therefore, it is essential to take a responsible and efficient approach to the use of electricity.