"We are slightly ahead of our schedule. If everything continues in this way, we can reckon with completion of the new power plant as early as the end of 2011," says a delighted Dr. Herbert Schröfelbauer, chairman of the board of AHP. Completion was originally planned for 2012. "The structural framework is in place, we are now working on the interior fittings of the pumped storage power station," explains Limberg II project manager Erich Wagner.
Top performances in the tunnelling
March 2006 saw the ground breaking ceremony on what is currently the largest power plant construction site in Europe. In record time, a tunnel system measuring a total of 5.8 kilometres was erected during the course of the opening up of the construction site. In the process it was possible to achieve top tunnelling performances of up to 24 metres per day.
The transformer cavern (61 metres long, 15 metres wide, 16 meters high) and the engine shaft, which is as large as the nave of St. Stephen’s cathedral, were completely broken through in July and December 2007, respectively.
In February of this year it was possible to complete work on the pressure tunnel, which is 750 meters long and angled at 45 degrees. At the end of March, the 900-ton-heavy and 240-meter-long drill of the headrace tunnel reached its goal after 3.5 kilometres.
In May 2008, excavation was accomplished on the approx. 20 by 30 meter service chamber in the Höhenburg section, which stands at an altitude of 2,000 meters. It is here that the pipe assembly for the plating of the inclined chute is now being temporarily housed. Manufacture of the piping was started at the beginning of July. The plating of the inclined chute should be finished at the end of May 2009.
Winter preparations successfully completed
By the end of November of this year, ahead of the first heavy snow fall, it was also possible to complete the preparatory measures for winter in the area of the Höhenburg construction site at an altitude of 2,000 metres. The large amounts of snow that fall here during the winter, and the associated risk of avalanche, make an access to this building section impossible from the beginning of December until the end of April. It is an enormous logistical challenge with which the power plant construction experts are confronted.
Thus, more than 20,000 tons of concrete aggregate such as sand and gravel, 9,000 tons of binding material such as cement and flue ash, and 3,500 tons of sheet steel, among others, which are required for the manufacture of the pressure tunnel plating in the service chamber’s temporary pipe manufacture, are transported up the mountain.
Works on the engine shaft are running according to plan
Rapid progress is being made on the concreting of the engine shaft, which began in mid January. The suction line, which has a diameter of more than four meters, has already been installed. After commissioning of the power plant, this will be used for drainage of the water that has already been employed in energy generation. Work is in progress on the lower generator floor. Work has also been started on preparatory measures for the concreting of both the intake and discharge structures in the Limberg dam and Mooserboden reservoir sections.
The preliminary works for the construction of the power transportation line, which will run from the engine shaft over the Bürgkogel down to the Tauern transformer station at the start of the Kaprun valley, have begun as well. The necessary access routes are being constructed, many of which will be used temporarily while others should remain as forest paths. 250 specialists are currently employed at the Limberg II construction site.