“Pumped storage power plants can absorb large amounts of energy and release it again during times of peak demand. This makes them a much-needed part of the energy transition”, says PORR CEO Karl-Heinz Strauss. “This project is particularly important for energy balance in Upper Austria”. With surplus electricity, water from Lake Traun is pumped almost 500m up into a storage facility in the mountains. In times of increased demand, green electricity is supplied from there; it does not have to be bought on the market or produced using fossil fuels.
The power plant is not only an important undertaking, but also a complex one: For example, in addition to earthworks and engineering work, the remit also includes the construction of the Traunsee outlet structure, the tunnelling and gallery construction, the construction of two plumb shafts, and the excavation of an inclined shaft with an unusually steep incline of 60°. Here PORR is applying its extensive experience in building pumped storage power plants. In addition to the Ebensee project, PORR is also currently constructing the caverns and galleries for the Limberg III pumped storage power plant in Salzburg, Rodund in Vorarlberg, both in Austria, as well as Forbach in Germany.
Spectacular work steps
The groundbreaking ceremony by Energie AG in October means that the preparatory work on the Ebensee pumped storage power plant is now underway. The pure construction time is around four years, and the power plant is scheduled to start trial operations at the end of 2027. “The necessary work steps sometimes seem spectacular due to the sheer size of the project. For example, the Traunsee outlet structure, a steel construction weighing several thousand kilograms, will be manufactured on the other side of the lake and then launched like a ship and pulled into place”, says Strauss.
“The expansion of energy storage facilities such as this pumped storage plant is a basic requirement to ensure the availability of electricity in the future energy system. Depending on the design, pumped storage power plants are able to cover a very wide range on the turbine and/or pump side. This allows them to react extremely flexibily and quickly to changes in demand and electricity generation. Thus, they make an important contribution to the security of supply”, explains Energie AG COO Stefan Stallinger.
Once completed, the cavern power plant will have output of 170 MW and a storage capacity of 1.32 million m3. The storage capacity allows ten full-load hours of operating time for power generation. The gross head is 491m.
In line with its Green and Lean strategy, PORR is also focusing directly on sustainability when it comes to construction site operations. For example, photovoltaic systems are being installed on the roofs of construction offices and the accommodation for the construction workers; e-vehicles are also being used.
Facts and figures at a glance:
| Project type: | Power plant construction, tunnelling |
| Scope of services: | Construction of a pumped storage power plant |
| Client: | Energie AG Oberösterreich Erzeugung GmbH |
| Contractor: | PORR Bau GmbH |
| Project duration: | October 2023 to February 2028 (trial operation end of 2027) |
| Contract volume: | EUR 167m |
