Types of electricity

Electricity can be classified into different types depending on how it is conducted and how it behaves.

1. Basic electricity

Matter, which is everything around us, is made up of tiny units called atoms. Atoms are so tiny that we cannot see them with the naked eye, but they are the "building blocks" that make up everything that exists, from a chair to the air we breathe. 

Electricity comes from the movement of electrons between atoms. Each atom is composed of three fundamental particles: protons, which have a positive charge; neutrons, which have no charge; and electrons, which have a negative charge. The protons and neutrons form the nucleus of the atom, while the electrons orbit around this nucleus.

Electricity is generated when electrons move from one atom to another. This movement of electrons, known as electric current, is what powers all the electrical devices and systems we use.

2. Static electricity

Static electricity occurs when there is an imbalance of electrical charges on the surface of an object. Under normal conditions, an object has a balanced number of protons and electrons, making it electrically neutral. However, when you rub an object, such as a balloon, against another material, electrons can transfer from one material to the other. This process creates an imbalance of charges: one object accumulates more electrons (negative charge), while the other is left with fewer (positive charge).

This imbalance of charges does not produce a continuous flow of electricity like an electric current. Instead, the accumulated charges remain on the surface of the object until they find a way to discharge, which can happen suddenly, as in a spark when you touch something made of metal after accumulating static electricity.

3. Dynamic electricity

Dynamic electricity refers to the continuous flow of electrons through a conductor. This type of electricity is what we commonly use in our homes and electronic devices.

Dynamic electricity is divided into two types:

• Direct current (DC): electrons flow in a single direction, from the negative to the positive pole. This type of current is common in batteries and portable electronic devices. For example, when using a flashlight, electric current flows from the battery, through the bulb, and back to the battery, creating a closed circuit.
• Alternating current (AC): electrons do not flow in a single direction, but change periodically. Alternating current is more efficient at transmitting electricity over long distances, which is why it is the most common form of electricity used in homes and industry.

Electricity can be generated from a variety of sources, each with specific characteristics and applications. They are mainly divided into two categories: renewable and non-renewable.

1. Electricity from renewable sources

The main sources of renewable electricity and their generation methods are:

• Hydropower: is one of the oldest forms of electricity generation. It is based on the movement of water in rivers or streams, using turbines.

• Wind energy: harnesses the power of the wind to generate electricity by means of wind turbines. Wind farms can be onshore or offshore.

• Solar energy: generated from solar radiation, it is mainly used in two ways:
  • Photovoltaic solar panels: directly convert sunlight into electricity.
  • Solar thermal plants: use mirrors or lenses to concentrate sunlight and generate electricity through steam.

• Geothermal energy: obtains electricity from heat stored beneath the Earth's surface. Steam from underground reservoirs is used to turn turbines and generate electricity.
• Tidal power: electricity is obtained from different marine phenomena:
  • Ocean thermal energy conversion: the difference in temperature between surface and deep water produces thermal energy from which electricity is obtained.
  • Offshore wind: uses the force of the wind captured from wind farms installed in the sea.
  • Tidal: generates electricity with the movement of rising and falling tides.
  • Wave: based on the movement of the waves to generate electricity.
  • Current energy: harnesses the kinetic energy of ocean currents to produce electricity.

• Biomass: Harnesses organic matter from plants and animals to generate electricity and heat. This energy source includes agricultural, wood, and forest industry wastes. It is considered a renewable energy source because its origin is organic and it can be replenished through cultivation and reforestation.

2. Electricity from non-renewable sources

Non-renewable sources remain a significant part of the global energy mix. They have been essential in industrial development and continue to play an important role in electricity production.

• Natural gas: versatile and efficient, widely used in power generation and other sectors such as heating and industry. Natural gas plants are adaptable to fluctuations in energy demand.
• Coal: it has been a cornerstone of electricity generation for many years. Its abundance and capacity to generate large amounts of energy have been essential for supplying growing populations.
• Crude oil: although mainly used in transportation, it also contributes to power generation, providing flexibility and capacity to adjust to demand.
• Nuclear energy: is a source of electricity that provides large amounts of energy in a continuous and efficient manner.

Our total installed capacity in renewable energies has exceeded 5,000 MW (megawatts), with projects ranging from hydroelectric and wind power generation to solar initiatives in Spain and Chile.

Advancing in power generation: more than 5,000 MW in renewables

Our infrastructure includes a wide range of renewable energy assets. In Spain, we operate 12 hydroelectric plants and one wind farm, and we are in the process of developing additional projects. These include two new wind farms, Delta 2 and PI, as well as 3 photovoltaic projects: Valdesolar, Kappa, and Sigma. Internationally, our presence is expanding with major wind and solar projects in Chile. Our goal is to reach an installed capacity of 6 GW (gigawatts) by 2025 and 20 GW by 2030.

Renewable energy production begins in Andalusia

One of the highlights is the Sigma project, our first major venture in Andalusia. Located in Jerez de la Frontera (Cadiz), Sigma has five photovoltaic plants with an installed capacity of 204 MW (megawatts). This initiative has required an investment of close to 150 million euros and has created more than 500 local jobs. Sigma is designed to supply energy to approximately 43,000 homes and contribute to the reduction of 191,000 tonnes of CO₂ per year, equivalent to the annual emissions of approximately 83,000 cars.