Electricity transmission grid facilities

In 2024, in an economic context marked by persistent high uncertainty, particularly of a geopolitical nature, investment in the transmission grid increased to 976 million euros, a 31.0% rise compared to the previous year.' These investments contributed to integrating a greater amount of renewable energy generation, boosting interconnection capacity, and improving the grid’s mesh structure, thereby ensuring supply security and service quality; in line with the guiding principle of 'maximising the use of the existing grid by renewing, expanding capacity, and leveraging new technologies.

Throughout 2024, transmission grid assets expanded by 487 kilometres of circuit and 197 substation bays, bringing the total length of line circuit in the national grid to 45,674 kilometres, a 1.1% increase compared to 2023. In addition, transformer capacity increased by 2,235 MVA, bringing the total installed transformer capacity nationwide to 97,216 MVA (2.4% higher than in 2023).

Facilities in the electricity transmission grid in Spain

Km

Annual evolution of the electricity transmission grid in Spain

Annual evolution of the transmission grid by systems

Among the projects carried out in the transmission grid in 2024, the following are the most important, according to their geographical area of development:

Andalusia: the synchronous static compensator ('statcom') at the Tabernas 220 kV substation was commissioned to improve supply security. Additionally, expansions were carried out at the Don Rodrigo and Puebla de Guzmán 220 kV substations. The El Zumajo-Puerto Real 220 kV line was also commissioned to improve support for distribution, and capacity increases were completed for the Atarfe-Tajo Encantada-Capacena, Casaquemada-Onuba, and Benahadux-Órgiva 220 kV lines, to promote the integration of renewables and resolve technical restrictions. In the 400 kV grid, the Tabernas substation was expanded to reinforce railway axes, along with the Pinar del Rey and Tajo de la Encantada substations to allow for new generation connections. Lastly, the Litoral de Almería 400 kV substation was upgraded to adapt it to gas-insulated technology, while the new Guadaira 220 kV substation was commissioned to support the distribution network in the area.

Aragon: several projects were completed to strengthen the transmission grid, support the distribution network, and enable better management of renewable resources. These initiatives include expansions at the Esquedas, Los Vientos, and Híjar 220 kV substations, and the Fuendetodos, Magallón, and Mezquita 400 kV substations. The new El Espartal 220 kV and Almendrales 400 kV substations were also commissioned to evacuate renewable energy generation.

Furthermore, the capacity increase for the Grado-Monzón 220 kV lines was completed. This will facilitate the integration of renewable energies and minimise technical restrictions in the area. Additionally, the implementation of dynamic line rating (DLR) devices on the Escucha-Híjar and Escatron-Hijar 220 kV lines was finalised, allowing for better renewable integration and reducing technical restrictions.

Balearic Islands: the Ibiza-Bossa 132 kV line was completed, and the new San Jorge 132 kV substation was commissioned to improve supply security.

Canary Islands: the Puerto del Rosario-Gran Tarajal 132 kV line and the input/output at Vallitos 66 kV were commissioned to improve supply security. Additionally, the capacity of the Granadilla-Arona, Jinamar-Lomo Apolinario, and Matorral-Lomo Maspalomas 66 kV lines was increased. The new Chío 66 kV substation was also commissioned, which will connect the islands of Tenerife and La Gomera, enhancing supply quality and security. Finally, two new transformers were commissioned at the Buenos Aires 220 kV substation, while the El Sabinal, Abona, and Corralejo 66 kV substations were expanded.

Castile and Leon: among other projects, the Magaña, Moncayo, and Alcocero de Mola 220 kV substations were expanded to promote the integration of renewables, resolve technical restrictions, and connect new generation.

Castile-La Mancha: expansion works were completed at the Puertollano 220 kV substation to support the distribution network, and the Brazatortas 220 kV substation was expanded to meet the power supply requirements of the railway lines. Finally, the Pradillos 220 kV substation was expanded to facilitate the connection of new generation. Additionally, the Manzanares 400 kV substation was expanded to improve the integration of renewable

Catalonia: the expansions of the Mangraners and Maials 220 kV substations were commissioned to improve supply quality in the area and facilitate the connection of new generation. Additionally, the Abrera 220 kV substation was upgraded to adapt it to gas-insulated technology. Notably, the commissioning of the circuit connecting the Mas Figueres and Palau 220 kV substations was completed to reduce technical restrictions in the area.

Extremadura: the new 220 kV lines Trujillo 1-Los Arenales and Cáceres-Los Arenales were commissioned to support the distribution network. Additionally, the input/output at the new Quintana de la Serena 400 kV substation, which will supply the railway line, was completed. New 400 kV substations at Fuente de Cantos and Maguilla were also commissioned to promote the integration of renewable energy generation and improve the resolution of technical restrictions in the region. Finally, the capacity of the Aldeadávila-Arañuelo 400 kV line was increased.

East of the Peninsula: the Benejama, Catadau, Morella, La Plana, and Requena 400 kV substations, as well as the Benejama and Novelda 220 kV substations, were expanded to improve distribution network support and facilitate the connection of new generation. Additionally, the capacity of the Godelleta-La Eliana and Torrente-La Eliana 400 kV lines was increased.

In the Murcia Region, the Peñarrubia 400 kV and San Pedro del Pinatar 220 kV substations were expanded to support the distribution network and facilitate the connection of new renewable generation.

Central Spain region: various improvements were made to the transmission grid to increase the capacity of electrical supply to new consumers. Expansions were completed at the Parla, Buenavista, Arroyo de la Vega, and Ardoz 220 kV substations, as well as at the Anchuelo and Morata 400 kV substations, to improve support for the distribution network and facilitate the connection of new generation. Additionally, the capacity of the Arganda-Loeches, Arganda-Valdemoro, and Hornillo-Pinto Ayuden 220 kV lines was increased.

Northern Spain region: in the Basque Country, the Gática 220 kV substation was renewed, and the 400 kV line between Güeñes and Ichaso was completed. This line is part of the axis that will connect the western Basque Country (Abanto-Güeñes axis) to Navarre’s 400 kV grid (Muruarte-Castejón axis), facilitating greater integration of renewable energy generation and ensuring the committed exchange capacity values between Spain and France.

In Galicia, expansions were completed at the Conso, Lousame, and Trives 220 kV substations to facilitate the integration of renewable energy sources, resolve technical restrictions, and enable the connection of new generation. The Lousame-Tibo 220 kV lines were completed, along with the reinforcement of the Cartelle-Castrelo line and the commissioning of dynamic line rating devices (DLR) at the Pazos de Borbén-Tomeza and Tibo-Tomeza 220 kV lines. Finally, work continues on the northern connection with Portugal, with the commissioning of the input/output lines that supply the new Beariz 400 kV and Fontefría 220 kV substations.

In La Rioja, the Santa Engracia 220/400 kV substation was expanded to facilitate the connection of new generation.

In Navarre, the capacity increase of the double-circuit La Serna-Tudela 220 kV line was completed to improve the integration of renewable energy and resolve technical restrictions.

In Cantabria, the Mataporquera 220 kV substation was renovated to adapt it to gas-insulated technology, and the expansion of the Aguayo 220 kV substation was completed to facilitate renewable the integration of renewable energy and resolve technical restrictions.

Interconnections continue to play a key role in the energy transition to achieve greater integration of renewable energy sources and progress in decarbonisation. The strengthening of international interconnections remains a priority for the coming years in the development of the transmission grid, as highlighted in the 21-26 Plan.

The latest interconnection commissioned between the electricity systems of Spain and France (Baixas-Santa Llogaia) at the end of 2015 doubled the electricity exchange capacity between Spain and France (from 1,400 MW to 2,800 MW), helping to reinforce the security of the two electricity systems and favouring the integration of a greater volume of renewable energy. However, despite this extension, the degree of interconnection in Spain remains below the targets set by the European Union, of 10% and 15% for 2020 and 2030 respectively.

The Spanish National Energy and Climate Plan (NECP) made this clear and proposed increasing the exchange capacity with Portugal to 3,000 MW and with France to 8,000 MW, by means of 3 new electricity interconnections. These objectives were confirmed in the latest revision of the NECP, approved in 2024. The interconnection between Gatika (Spain) and Cubnezais (France) will be the first fundamentally submarine interconnection between Spain and France ('Gulf of Biscay' project); and two other projects across the Pyrenees (Navarre – Landes, and Aragon – Marsillon)¹.