In June 2008, France and Spain decided to establish an electrical interconnection between Perpignan, France, and Figueres, Spain, by establishing a DC underground cable using, wherever possible, the routes of existing infrastructure. The investigation initially focused on a route using a trench, but that was not possible. So a tunnel solution was adopted to cross the Pyrenees Mountains. The underground cable route has an overall length of 64.5 km (40.1 miles), with 32 km (19.9 miles) in Spain and 32.5 km (20.2 miles) in France. In the tunnel, 8.3 km (5.16 miles) of cable is installed.
Following are images of the process. The project is discussed in detail in the June issue of T&D World in "Crossing Mountains to Connect Two Countries."