Autor: Roland Gruber , 05.02.2013

The Sohlstufe Lehen power plant, a run-of-the-river power plant in the northern part of the city of Salzburg, is to be commissioned soon. The two generators with a weight of 37 tons are the core pieces of the new plant.

They were brought to the site in a heavy load  transport and lifted into the powerhouse on March 7, 2013. They are scheduled to be installed within the next few weeks, together with the turbines, which will arrive soon. The power unit of the plant will be launched in mid 2013 and will produce about 81 million kWh of clean electricity in a year on average.

The realization of the Sohlstufe Lehen power plant, which now enters its final constructing stage, is one of the most exciting and interesting power plant projects in Austria. The biggest part of the construction works has been completed and the mechanical engineers are set to equip the power plant with the electromechanical components. On Thursday, March 07, 2013, the heavy load transporters arrived at the construction site, delivering the synchronous generators, which will soon transform the mechanical energy of the turbines into electricity. The heavy load of 37.3 tons was supplied by renowned Austrian manufacturer ELIN Motoren GmbH, based in Preding/Weiz. The three-phase synchronous generators run with a nominal rotation speed of 600 rpm and have a nominal output of 9,000 kVA each. Quality ELIN Motoren generators stand for top degrees of efficiency and a robust design, which guarantees high availability. The generators are to be installed together with the turbines within the next few weeks and should be operating by midyear.

The machine units are designed for a design flow of 125 m³/s. In total, the two Kaplan turbines, when operating at full capacity, will process 250 m³/s of water from the Salzach River. The runners are dimensioned accordingly, with a diameter of four meters. Their nominal rotation speed is 115 rpm, which is transformed into 600 rpm of generator rotation speed by the interconnected spur gear unit. With a head of 6.60 meters the two turbines have a bottleneck capacity of 13.7 MW. With this output the newest power plant of Salzburg AG company will produce 81 million kWh of clean electricity per year
on average, sufficient for 23,000 households in the northern part of Salzburg.

From the beginning, producing energy has not been the only focus of the project, although the convincing capacity figures may suggest otherwise. The construction of the power plant, which is close to being finalized, brings additional benefits, which is why the plant has experienced a huge support by the residents of Salzburg. Firstly, the flood control is improved through the project's various accompanying measures. Secondly, the groundwater situation in Salzburg is stabilized. Thirdly, as one of the most important aspects of this project, the power plant helps prevent the increasing bed degradation of the Salzach River. The comprehensive river engineering measures along with the production of clean, green electricity form a synergetic unit. The representatives of the project attached importance to meeting a high ecological standard with the plant right from the start. A passage for fish at the existing vertical hard basin drop structure will be installed, a flood discharge flume will be recultivated and riparian forests will be reforested - to name only a few ecological measures. Furthermore the new design of the surrounding Glanspitz natural area influenced the shape of the project. Currently a local recreational area is being built with footpaths and bike trails for the residents of Salzburg, whose many ideas helped in the creation. There are plans for playgrounds and resting spots and an expansion of sports and spare time facilities is being elaborated as well.

The energy supplier of the province of Salzburg is investing no less than 85 million euros in the project of the Sohlstufe Lehen power plant. The construction works began in the summer of 2010 and are now close to being completed. The project involved the local residents to a large extent. The focus of all participating parties lay on the development of the construction site, which resulted in directing the biggest part of the heavy load traffic through an individual highway access. The constructive dialogue with the residents of Salzburg played a key role in the successful construction of a hydropower plant of this size in an Austrian provincial capital. Another great achievement is the architectural design of the weir by architects Erich Wagner and Max Rieder. Salzburg AG has set a sign for the development of the city by combining a whole range of various additional benefits in one plant – more than any other hydropower plant in Austria.

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The new Sohlstufe Lehen in Salzburg, Austria











The new Sohlstufe Lehen power plant helps prevent the increasing bed degradation of the Salzach River. As planned, the power plant will be put into operation this summer. (photo credits: Salzburg AG)

Video about the working progress (in German)

1st machine unit component



The synchronous generator with a weight of 37 tons is being heaved carefully into the plant. (photo credits: Salzburg AG)

The synchronous generator



The synchronous generator by ELIN Motoren has reached its final destination. (photo credits: Salzburg AG)

Technical characteristics

Video about the project (in German)