Electricity transmission grid

We have more than 45,000 km of line circuits that make up a meshed, reliable and secure network serving the entire country.

What is the transmission grid?

The electricity transmission grid is the backbone of the electricity system. It connects the electric power generation centres with distribution points and large consumers, as well as linking the national electricity system with neighbouring countries' systems.

Since the electricity generation plants and demand are in different locations, a grid is needed to transmit this energy efficiently and safely.

It is an essential service of general interest, so this activity is regulated through national regulations.

A meshed and secure network

The transmission grid comprises a set of facilities that forms a connected system so that electricity is accessible to the entire community safely and reliably. In Spain, the transmission grid operates mainly at 400 kilovolts (kV) and 220 kV on the peninsula, while in the Balearics and Canary Islands it runs at 220 kV, 132 kV, and 66 kV.

It consists of over 45,000 kilometres of high-voltage line circuits, more than 700 sub-stations, 6,000 bays, and over 200 transformers. These assets configure a meshed, reliable, and secure grid, providing the highest level of service quality to the national electricity system.

Transformers of generation groups, elements connecting these groups to the transmission grid, consumer installations for their exclusive use, and direct lines are not part of the transmission grid.

Primary transmission grid

Lines, switchyards, transformers, and other electrical elements with nominal voltages equal to or greater than 400 kV.
Interconnections with non-peninsular territories' electricity systems.
International interconnections.

Secondary transmission grid

Lines, switchyards, transformers, and other electrical elements with nominal voltages equal to or greater than 220 kV not included in the primary grid and other facilities with nominal voltages lower than 220 kV that perform transmission functions.

Network elements

Substations

They are the facilities that act as nodes between generation and the transmission grid, or between this grid and the distribution one.

Power lines

They are the circuits that transmit electricity, forming a meshed network to ensure supply throughout the country.

Transformers

They are the components of the electricity system that enable the flow of power between different voltage levels.

Other elements

Sub-stations require secondary systems to operate. For example, control, protection, and communication systems.

Learn more about our infraestructure

Construction and maintenance

To design and build a transmission grid facility, we always start with a rigorous social, technical, and land survey of where it will be located.

Once the infrastructure is in service, we ensure it is always in optimal availability, reliability, and safety conditions by following an annual maintenance programme.

How is the development
of the transmission grid planned?

Electrical planning is the regulatory instrument approved by the council of ministers that establishes the necessary developments in the transmission grid.

Access the planning