The project of building a high-voltage power line between the towns of Langreo (Asturias) and Velilla del Río Carrión (Palencia) through the Cantabrian Mountains is known as the electrical highway Sama-Velilla. This project aims to build a double circuit of 400 KV power stations connecting Lada and Velilla, which means running for almost 124 miles through a total of 19 municipalities. The project would cross protected areas, the habitats of endangered species such as the brown bear and the Cantabrian capercaillie. Proponents of the project appeal to the need to export the excess energy out of Asturias. For the coming years it seems that various current electricity generation projects will have excess capacity and according to the proponents, the two existing lines are insufficient.

However, since the proposal of the project in 2007, opposition has increasingly been growing from citizens, social movements, town councils, environmental groups and political parties. Thus, all the municipalities affected by the electric highway have expressed their rejection of it. Opponents claim the line will deface some the only remaining pristine valleys in the region and they also claim that the impacts of the electro-magnetic radiation from the line are uncertain but that it could be damaging to human and animal health. On the opposite side, the Asturian government, together with the Ministry of Industry and the company promoting the project, Red Eléctrica de España, are defending the construction of the high power lines.

Among the many actions taken by the opponents there are several demonstrations in both Asturias and León, the appearance before the European Commission and the submission of 27,000 claims against the project. These were rejected by REE and the opponents replied by starting a legal process. In february 2008, the platform against the sama-velilla electrical highway joined other groups in Spain struggling with the same sorts of projects (Valencia and Cataluña), to coordinate efforts against high power lines.

Currenly, the project is frozen mainly due to the Spanish economic crisis and lack of investment. The current right-wing government has announced that the project is not urgent and wont be executed before 2016.

Affected municipalities: Langreo (Asturias), San Martín del Rey Aurelio (Asturias), Laviana (Asturias), Aller, (Asturias), Cebanico (León), Cistierna (León), La Ercina (León), La Pola de Gordón (León), La Robla (León), La Vecilla (León), Matallana de Torío (León), Prado de la Guzpeña (León), Santa Colomba de Curueño (León), Valderrueda (León), Vegacervera (León), Vegaquemada (León), Villamanín (León), Guardo (Palencia), Velilla del Río Carrión (Palencia).

Tensión nominal: 400 kV.

Número de circuitos: Uno.

Número de conductores por fase: Dos.

Tipo de conductor: Dúplex Rail.

Cable de tierra: Dos cables compuestos de tipo Tierra- óptico.

Tipo de apoyos: Torres metálicas de celosía.

Cimentaciones: De patas separadas de hormigón en masa.

Puesta a tierra: Anillos de varilla de acero descarburado.