Ötztaler Wasserkraft GmbH intends to build a hydropower plant to use the drop between Tumpen and Habichen on the Ötztaler Ache to generate power. The scheme proposes a diversion power plant for run-of-river operation with a design flow of 22 cubic metres per second. The proposed hydropower plant will consist of the following components: reservoir, water intake structure including a residual flow power station, a headrace channel, a powerhouse and tailrace channel.
The project partners work together in a consortium consisting of the two project municipalities of Umhausen and Ötz, Auer Wasserkraft GmbH based in Umhausen, and TIWAG.
The reservoir has a storage capacity of only around 7,000 m3 and is used exclusively for drawing off water and not for storing the available water over time. Up to 22 m3/sec of the inflowing water will be used to generate electricity. At Habichen, where the powerhouse is located, three Francis turbines will convert the energy of the water into eco-friendly electricity for 15,000 households.
The water is fed back into the river via the subterranean tailrace channel.
|Natural catchment area||769.9 km²|
|Mean discharge||26.5 m³/s (Tumpen flow gauge)|
|Design flow QA||22.0 m³/s|
|Altitude of headwater level (full supply level)||919.00 m a.s.l.|
|Altitude of tailwater level for QA||841.80 m a.s.l.|
|Gross head||77.20 m|
|Ned head for QA||75.37 m|
|Length of headrace channel||1,000 m|
|Turbines||3 Francis turbines|
|Max. turbine output||14.48 MW|
|Average annual output||approx. 61 GWh|
|Residual flow power plant|
|Design flow QA||4.0 m³/s|
|Gross head||3.20 m|
|Turbine||1 Archimedean screw|
|Max. turbine output||103 kW|
|Average annual output||approx. 625,000 kWh|
Based on the approvals obtained and because expiration of the approval under nature conservation laws was imminent, implementation started in the spring of 2020, twelve years after the project was first proposed. Commissioning is scheduled for 2022. More than 85% of the total investment volume will go to local Tyrolean companies, and over 95% of the companies employed and services provided will be sourced from Austrian businesses.
Will the power plant expose local residents to an increased risk of floods and mudslides triggered by the Acherbach stream?
As the Acherbach flows into the Ötztaler Ache upstream of the power plant, the structure can in no way influence these natural hazards. Moreover, the bedload retention basin built in recent years has a retention volume of 200,000 m3 and is designed for an event that occurs once every 150 years on average.
Will the power plant change the risk of flooding by the Ötztaler Ache for the village of Tumpen?
The future flood hazard for Tumpen will be lower than it is now once the power plant has been completed. This aspect was dealt with extensively in the project proceedings and was confirmed by the expert reviewers. In case of flooding, which is to be expected once a year, the sluice gates will be positioned automatically, and the deepening of the river bed will cause the floodwater level at the weir to be about 1.5 m lower than today's level.
Will it still be possible to stage the Kayak World Championship after the power plant has been built?
The Kayak World Championship route starts at the Wellerbrücke bridge considerably below the point of confluence. Consequently, no construction work will be carried out there. The power plant is designed for run-of-river operation and will therefore not affect the water regime in this part of the river in any way. There is no influence of the power plant on the Kayak World Championship.
What kind of ecological changes are to be expected along the residual water section between the water intake structure and the point of confluence?
The water regime is reduced in the residual water section of the river but this will not cause degradation of the body of water. This has been confirmed by a number of different experts including the WWF reviewer.
Besides, the residual water section will be closed to hikers year round due to rockfall hazard.
For more information, please contact Managing Director Klaus Mitteregger on tel. +43-699-12572365 or building contractor Klaus Auer on tel. +43-664-4214455.