In spring 2023, Swissgrid and SBB submitted a planning application for the replacement of the high-voltage submarine cables between Brusino and Morcote. A total of six Swissgrid and two SBB cables will be replaced along the cable route, which is 2.8 km long. The total cost is approximately CHF 8.7 million. Work is scheduled to begin in 2024. Swissgrid’s 150-kV line between Manno and Mendrisio guarantees the supply of electricity for the Sottoceneri, while the 66-kV line is crucial to enable SBB to ensure the functioning of the railway network, especially in the Ceneri Base Tunnel.
By submitting the planning application to ESTI for the replacement of the high-voltage submarine cables, Swissgrid and SBB are laying the foundations for guaranteeing the supply of electricity for the Sottoceneri and the Ticino railway network. The total length of the cable route is 2.8 km (consisting of a land section measuring 400 m between the portals and the banks of the lake, and a lake section measuring 2,400 m). A total of six 150-kV Swissgrid cables and two 66-kV SBB cables will be replaced.
The cable routes between the Brusino and Morcote portals were built by AET and SBB in the 1980s (a second cable route was built by AET in 2008). Considering that underground cables have a lifespan of about 40 years, the oldest cables therefore need to be replaced. If everything goes smoothly, work should start in 2024 and be completed within around two years. The total investment amounts to CHF 8.7 million (Swissgrid: CHF 6.3 million and SBB: CHF 2.4 million).
Technical data and construction phases
All the cables laid in the 1980s will be replaced in the course of this project. Two 150-kV Swissgrid lines and one 66-kV SBB line are currently located on the lake bed. A three-phase line consists of six cables at Swissgrid and two cables at SBB. The new SBB cables will first be inserted into the two spare cable conduits that are currently empty. This means that the SBB line can be put into operation immediately. After that, the six Swissgrid cables will be replaced. The cross section of the copper cables used is 630 mm2 on the land route and 300 mm2 on the lake route. The transition from an overhead line to an underground cable is possible thanks to the overhead line/cable transition facilities in Brusino and Morcote.