Transmission grid

The infrastructure responsible for delivering electricity to customers is known as the transmission grid.

What is the transmission grid?

The transmission grid includes electrical lines, substations, and transformation centres that enable electricity to be taken from the transmission network where it is generated, and transported it to where it is consumed.

Distribution companies are in charge of maintaining, developing, and operating this grid, which consists of:

Electric substations: they transform electrical energy between various suitable voltage levels for efficient distribution. They are commonly located near power plants or on the outskirts of cities, although in large cities they are housed in underground facilities.
Transformation centres: these convert medium voltage into low voltage in order to supply energy to different consumption centres.
Distribution and transmission lines:
- High voltage lines exceed 30 kV and are generally used to transport large amounts of energy over long distances, connecting with the transmission network and large electrical production centres.
- Medium voltage lines support voltages ranging from 15 kV to 30 kV. They are used to transport energy from electrical substations to transformation centres, connect renewable generation centres, or industrial customers. Low voltage lines can be installed on metal towers, wooden and concrete poles, or be underground.
- On the other hand, low voltage lines are the ones that ultimately deliver energy to consumers: households, public lighting, industry, etc.
Metering equipment: Metering equipment tracks energy usage and production at the supply point.

The electricity distributor responsible for delivering power to your location is determined by your geographical location and cannot be selected.

The access toll or access fee that appears on your bill is used to cover the costs of maintaining the electrical grid and delivering energy to your supply point. The Government sets the price of this toll, which is the same for everyone, regardless of location or company.

Role of the electrical grid in the energy transition.

In order to achieve the decarbonisation of the economy, it is essential for energy generation to be emission-free, as well as for energy demand to be met with clean technologies. The electrical grid plays a crucial role in that process.

The energy transition poses significant challenges for the electrical grid, such as the integration of renewable energies and energy storage, electric vehicles, distributed generation, and the development of self-consumption.

Climate change and increasingly frequent extreme weather events, pose a challenge to the network, which must be strengthened to enhance its resilience.

The digitalisation and technological innovation are key in this process, as they allow for a more flexible and adaptive operation of the grid.

To meet these challenges, it will be necessary to design new flexibility mechanisms such as demand management and implement technologies such as the Internet of Things (IoT), artificial intelligence (AI), and big data, which allow for better observability of the network. This digitalisation leads to greater efficiency in electrical distribution, optimising maintenance, improving fault detection, and facilitating the integration of renewable energy sources, allowing for better service quality at a lower cost for the system.

The Endesa distribution and transmission grid

Through our subsidiary e-distribution, we manage an extensive electrical distribution network, which plays a key role in the energy supply.

Endesa 2023 transmission grid

12.5 million customers
1,337 substations
319,136 km transmission grid lines
131,452 transformation centres

Versión accessible

E-distribution supplies electricity to 24 provinces in Spain, spanning eight Autonomous Communities (Andalusia, Aragon, Balearic Islands, Canary Islands, Catalonia, Extremadura, Castile and León, and Galicia) as well as the Autonomous City of Ceuta.

The number of customers with access contracts to our distribution networks reaches 12.5 million and the length of our distribution network lines is 319,136 kilometres, of which 41.1% are underground lines.

The e-distribution management strategy focuses on optimising the existing infrastructure and investing in new technologies to enhance the quality and efficiency of the service.

Facilities in the electricity transmission grid in Spain	2023
Length of transmission grid lines (km)	319.136
Length of high voltage transmission grid lines (km)	19.711
Length of medium voltage transmission grid lines (km)	115.069
Length of low voltage transmission grid lines	184.356
Substations (number)	1.337
Substations (MVA)	91.255
Transformation centres (number)	131.452