ELECTRICAL SUBSTATIONS IN SPAIN
Electricity substations in Spain: what they are and why they’re key to the national electricity system
Electricity substations are essential for the efficient transmission and distribution of electricity. These facilities act as connection points to transfer electrical power from generating plants to end consumers. They ensure that electricity reaches homes, businesses and industries in a stable and safe manner.

What are electrical substations?
Electrical substations are installations designed to establish the right voltage levels for producing, converting, regulating and distributing electrical power. They make changes in the voltage, frequency, number of phases or vector group to ensure electricity is transmitted correctly from power stations or power plants to the places where it is needed.
As vital elements along the electricity grid, their main functions are to control and manage electrical power efficiently, as well as to integrate renewable energies into the grid. Since the construction of the first electrical substation in 1882 in New York, their evolution has been key, especially with the introduction of power transformers in the 1930s, which allowed for more precise control and flexible distribution of electrical power.
Types of electrical substations in Spain
There are different types of electrical substations, whose classification depends on different criteria, such as location or site:
- Indoor substations: These are concealed within buildings and are designed to blend discreetly into urban environments and reduce their visual impact.
- Outdoor substations: These substations are ideal for rural or peri-urban areas where there is enough space to build and no need for concealment.
- Offshore substations: Located at sea, the main purpose of these substations is to transfer electricity from offshore wind farms to onshore substations. They are characterised by their robustness and resistance to adverse weather conditions and vibrations caused by waves.
- Mobile substations: They can be moved from one location to another as required. They’re mainly used in emergency situations, such as natural disasters, or when new infrastructure is being built or when existing substations are being upgraded.
Parts of an electrical substation



These are the elements that make up an electrical substation
In addition to the main parts, electrical substations may be equipped with a variety of auxiliary components, such as emergency back-up generators, batteries and cooling systems. This equipment plays a crucial role by providing back-up power in black or brownouts and by ensuring the optimal operation of the main components.
How do electrical substations work?
Power substations play a crucial role in the energy infrastructure. These facilities receive the electrical power generated in power stations and power plants to raise the voltage of the electricity and ensure it is safely transported over long lines to urban areas and other consumption centres.
Once there, the voltage is reduced again for transfer over medium-voltage lines, which transmit the energy to transformer stations located close to the consumers, where it is adjusted to levels that are safe for household use.
Map of Iberdrola España's electricity substations


Our innovation in electrical substations in Spain
The evolution of electrical substations responds to the need for greater capacity and efficiency in producing and distributing electrical power. The increase in demand has led to the expansion of facilities and the adoption of more advanced technologies, in addition to providing greater security and reliability in the supply of electricity.
Iberdrola España has more than 97,000 transformer stations and almost 1,200 substations to supply electricity to more than 11 million supply points around the country.
Iberdrola España electrical substations
Iberdrola España's electricity distribution company, i-DE, manages the company's electrical substations. Below we’ll describe several of them:









i-DE workers at the electrical substation of Las Cinco Torres in Madrid