Project
Background
The Gotthard line Airolo - Mettlen was built in 1933 (150 kV), the voltage was increased to 220 kilovolts at the end of the 1950s. Part of the line has reached the end of its service life and needs to be renovated due to its age. For the first time, an extra-high voltage line will be bundled with a national road tunnel. At the time of its planned commissioning, the approximately 18-kilometre-long Gotthard line will be the longest underground extra-high voltage line in Switzerland.
Swissgrid's extra-high voltage line Mettlen - Airolo runs over the Gotthard and is important for transporting electricity in Switzerland from north to south.
Extra high voltage in the road tunnel – a trailblazing project
The second tube of the Gotthard Road Tunnel will transport electricity as well as road traffic in the future. In cooperation with the Federal Roads Office (FEDRO), Swissgrid is installing a 220-kV cable line in the tunnel between Airolo (canton of Ticino) and Göschenen (canton of Uri). The new line will be laid in the service duct under the emergency lane.
The Swiss Federal Inspectorate for Heavy Current Installations (ESTI) granted planning approval for the construction of the cable line in March 2025. The new line between Airolo and Göschenen will cost more than CHF 100 million.
It is a pioneering project: this is the first time that an extra-high-voltage line will be laid in a motorway tunnel. At the time of its commissioning in 2030, the new cable line will be the longest underground extra-high-voltage line in Switzerland, covering a length of approximately 18 kilometres. The Gotthard project will provide new insights into the use of extra-high-voltage cable lines in long tunnels. The technical feasibility of the project has been investigated by the relevant authorities, and Swissgrid will comply with all safety regulations and emission limit values at the Gotthard.
