Construction of both plants, by Austria’s Tyrolean utility company TIWAG, commenced in spring 2005 and is expected to cost US$42M. The projects are designed to produce a combined 99GWh/yr.
The 9.9MW Schwarzach hydro plant has a design discharge of 4.6m3/sec and a head of 264m. It is expected to generate 59GWh/yr, and water from its 290km2 catchment area will be diverted downstream from the community of Hopfgarten in the Defreggen valley into a 4.3km penstock which links the intake to the power house in the Isel valley, near the village of Huben. Electricity will be transported via an underground cable to a nearby substation at the existing Kalserbach hydro plant.
Dorferbach hydro plant has a maximum capacity of 9.8MW and is set to generate 40GWh/yr. It has a design discharge of 1.8m3/sec and a head of 685m, and will divert water from a 27.2km2 catchment area, draining the southern flank of the 3672m high Grossvenediger mountain.
Both plants will have a single vertical Pelton turbine, with six and four nozzles respectively, and a synchronous generator. All planning stages from pre-feasibility study to tender procedure, site management and surveying are carried out by TIWAG personnel.
