Hieflau Power Plant

The Hieflau power plant is a diversion plant on the river Enns and has the day storage reservoir in Wag. It was constructed in the 1950s and was expanded and modernised between 2007 and 2013, today the power plant has the highest output capacity of any hydropower plant in Styria.

In the Hieflau powerhouse, there are three machine units with vertical shafts and an installed capacity of altogether 63,000 kW. Every machine unit is made up of one Francis spiral turbine and one three-phase synchronous motor. The powerhouse, which is located in the same power plant of Hieflau-Erzbach, also uses a gradient level of the Erzbach for generating energy and for its own power supply. 

Wag Reservoir

The Wag reservoir, a reservoir created by dams, has a top water level of 565.5 m. The useful capacity is 1.66 million m3. From the surge tank and from the reservoir there are three 260 m long steel pressure pipes leading to the Hieflau powerhouse at the foot of the Wag plateau. 

At the Hieflau power plant, a big stack of ecological accompanying measures were implemented. In the immediate vicinity of the Gesäuse national park, four times more water will be fed into the river Enns after the rebuilding, so that even a reintroduction of the Danube salmon will become a possibility. In the course of the expansion measures, the Gstatterboden weir was equipped with a modern fish ladder. 

Technical data:

Owner: VERBUND Hydro Power GmbH
Operating company: VERBUND Hydro Power GmbH                                 
Beginning of operation: 1956/2009
Type:  Storage
Country, State: Austria, Styria
Waters: Enns
Capacity: 63 MW
Annual generation: 369.653 MWh
Turbines: Francis (3)
Fish bypass: yes