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Kops II Pump Storage Power Station

The growing significance of renewable energies and the increasing demand for peak and operating electricity supplies on a liberalised energy market represent the main reasons for setting up the Kops II power station. In addition, the economy of the entire "Obere III Lünersee" can be augmented by Kopswerk II. The power plant is being provided with an additional turbine generating 450 MW ln this way, the "Obere III Lünersee" power Station group will be able to increase output by 36 % to 1,700 MW. In pump mode, the group's capacity will in fact, be increased by all of 85 %. The pump Storage power station is to be constructed with only one underwater feed, in other words, the operating water runs in the same tunnel both in turbine and pump mode. The power station is to be provided with 3 sets of turbines, each generating 150 MW- and possesses a drop height of 800 m. The entire facility is split into 3 contract sections: Section 1: pressure tunnel "Versal" including inlet structure, lock chamber and relief shaft as well as material and access tunnels. Section 2: "Außertafamunt" pressure shaft including access and material tunnels and surge tank. Section 3: Cavern power station plus all auxiliary facilities and underwater guidance system. The complicated accesses place high demands on the logistics. Excavation Started with the enlargement of the exploratory gallery to produce the cross-section of the utility tunnel (22 m²), which was driven further to reach the transformer cavern. The transformer cavern was then excavated and in turn, the machine cavern. The transformer cavern was excavated in a crown and 3 bench levels; the machine cavern in a crown and 10 bench levels. The crown drive in the machine cavern was carried out via 2 side wall headings and follow-up core excavation. Up to 32 m long pre-tensioned strand anchors, capable of sustaining a useful load of 1,250 kN, were installed as permanent supports in the machine cavern. A crane way was set up for installing the generators and turbines as well as for subsequent maintenance work. Two 150 t cranes will eventually use the crane way. The steep access and ventilation tunnel (70 m, 18.5 m²) leads to the surge tank from the transformer cavern, from which a 124 m long cooling and extinguishing water tunnel (186 m²) branches off. The 195 m long mucking tunnel (25 m² cross-section, gradient 23 %), via which the underwater area is opened up, was driven parallel to the excavation work in the upper water area. ln the underwater area, the pump water tunnel (65 m, 40 m²), the pump distribution pipeline (70 m) and the underwater tunnel (340 m, 56 m²) have to be driven one after the other. The vane actuator tunnel (76 m, 87 m²) is to be driven via the power station access tunnel and from there the turbine feed lines (each 23 m, 14 m²). These are excavated with a larger cross-section for operational reasons. Pumpable emulsion explosive (Emulgit), which is produced on the spot in mobile mixing plants, is used for blasting purposes.

 

  • Country: Austria
  • Region: Voralberg
  • Tunnel utilization: Utilities
  • Type of utilization: Power Generation
  • Client: Vorarlberger lllwerke AG
  • Contractor: Jäger Bau GmbH, Beton- und Monierbau Gesellschaft m.b.H., Ed. Züblin AG, Alpine Mayreder Bau GmbH
  • Main construction method: Trenchless
  • Type of excavation: Drill-and-blast
  • Lining: Shotcrete
  • Tunnel total length: 1650 m
  • Cross-section: Cavern power station 90/70 x 30 x 61 m high, Transformer cavern 35 x 16 x 20 m high, Surge tank - shaft height 32 m, diameter 13 m; 1,615 m of tunnels, with cross-sections varying from 11 to 87 m²
  • Contract Volume: € 350 million
  • Construction start/end: till late 2007