After eleven months of construction, at the beginning of August 2021, the breakthrough in the approximately four-kilometer-long access tunnel to the future cavern power plant took place. The BERNARD Gruppe is working with planning partner AFRY on behalf of Österreichische Bundesbahn Infrastruktur AG (ÖBB) on the execution design for this construction project in Salzburg.
With the expansion of the Stubachtal power plant around the Tauernmoos pumped storage plant, the ÖBB focuses on sustainable and environmentally friendly mobility. Between the two existing reservoirs Weißsee (2250 m above sea level) and Tauernmoossee (2023 m above sea level) in the rear Stubachtal valley near the municipality of Uttendorf (Oberpinzgau), the unused net head of 220 m will be used to generate 460 gigawatt hours of traction current (approx. 124,320 Railjet journeys from Salzburg to Vienna, distance 312 km, travel time approx. 2.5 h).
The planned structural and electromechanical power plant facilities are largely housed in an underground tunnel and cavern system. The approx. 8 km long tunnel system provides access to the existing facilities and the new cavern power plant, which in future will be accessible from the public transport network at Enzingerboden regardless of the weather. The heart of this power plant are the two reversible Francis pump turbines with a total capacity of 170 MW, which are located in the underground machine cavern. The height of this cavern is equivalent to a twelve-storey high-rise building. The turbines are fed via the approx. 2 km long underground pressure tunnel, which transports 80 m³ per second in turbine mode and 70 m³ per second in pump mode. The generated traction current is fed via an underground 110 kV cable system to the Schwarzenbach substation (Uttendorf municipality), which has already been built, and from there it is fed into the 380 kV high-voltage grid of Austria Power Grid or into the 110 kV high-voltage grid of ÖBB.
The BERNARD Gruppe was commissioned in a planning consortium with the design and project management services for this construction project. In the past, our services included the preparation of EIA submission documents and tender documents. Currently our staff is working on the execution design and geotechnical construction supervision.
Matthias Pertl, BERNARD Group
Photo: © ÖBB, EQvis