Domains
Hydropower;Tunnel & Underground
Client
AXPO AG
Time frame
Construction cost
CHF 1'800'000'000
Services
- Design
- Technical site supervision - QA/QC
Phases
- Final design
- Permit-obtaining procedure
- Tender design
- Construction design
- Construction
- Commissioning, completion
Services in JV with partners
The Project
Europe’s highest dam powers a hydroelectric power station inside a cavern.
The Linthalproject is exceptional because it combines a record-breaking engineering effort (the dam, over one kilometer long, is also the longest in Switzerland) with a vision of sustainable development. The power station is reversible. This means that it can pump water to the upper reservoir (Muttsee) for later use. It works like a large storage battery, storing electricity for when it is needed.
Maxi-hydroelectric power station in the heart of the Alps
The Limmern PSPP (1’000 MW) is a new underground hydroelectric power plant integrated into the existing power plants of Linth-Limmern hydroelectric complex, boosting the overall installed capacity from 480 MW to 1’480 MW. The plant is using the enlarged Lake Mutt (2’474 m a.s.l.) as an upper reservoir and the existing Lake of Limmernboden (1’854 m a.s.l.) as a lower reservoir. The underground power station consists of a power-house cavern with the 4 machine groups of 250 MW each (in pumping and turbine mode). It also includes a transformer cavern with the 4 transformers of approximately 200 tons each that convert the voltage of the generators from 18 kV to 400 kV. The energy produced feeds into the Swiss extra-high voltage grid. Other underground works for the project: a head-race pressure tunnel with prestressed concrete lining; a surge shaft with reinforced concrete lining; 2 head-race pressure tunnels (2 x 1’030 m, D 5.20 m and 40° inclination ca. 84%); 2 tailrace pressure tunnels (2 x 500 m, D 5.50 m) with prestressed concrete lining; and several access tunnels and caverns including a smoke extraction shaft (L 252 m, D 4.20 m, inclination 98%).
The Linth Limmern project was extremely motivating both in terms of its scale, diversity, and the rare opportunity for us to be involved from the preliminary design review to commissioning
Personally, it constituted a significant portion of my professional life, spanning 7 years dedicated solely to it. Carried out in a JV, it also provided the opportunity to meet numerous colleagues from other engineering firms, as well as from the client.
