Kühtai power plant construction

“Snail” walled in for 100 years of service

Exclusive insight into the gigantic underground cavern: the "water snail" will soon be walled in.(Bild: Hubert Daum)

The construction of the underground Tiwag power plant in the mountain cavern is progressing according to plan. The dimensions of the extension in Kühtai are breathtaking for the layman. The "snail" for the water inflow is being given a concrete casing, which must last around 100 years!

The mere fact that the expansion of the Tiwag Kühtai power plant cost over a billion euros gives an idea of the dimensions. And the exclusive insight that the energy company gave media representatives confirmed the superlatives.

Increasing annual production by 40 percent
The bus ride into the interior of the mountain reveals several tunnel branches similar to those of a labyrinth, until finally reaching the 40 meter high and 25 meter wide cavern. The future heart of the Sellrain-Silz power plant extension, which will increase annual electricity production by 40 percent.

For this purpose, the new "Kühtai" reservoir, which is about half the size of the existing "Finstertal" reservoir, was also created for the new pumped storage power plant. The water coming from both reservoirs will drive two Francis turbines underground. The turbine components have been delivered and installed in several stages since August 2023.

What project manager Klaus Feistmantl is explaining to journalists here on the screen will be shown live in September.(Bild: Hubert Daum)

No need for another 220 kV line into the Inn Valley
"Last opportunity to view the snail-like feed lines to the turbines," explains Project Manager Klaus Feistmantl, "they will soon be walled in for stabilization so that they can be used to generate electricity for the next 100 years." Tiwag's plans to put the pumped storage power plant into operation in 2026 are also stable. In times of surplus electricity, the water will be pumped back up into the Finstertal reservoir to generate new energy.

The electrical energy is supplied and discharged via a short, underground 220 kV cable connection to the existing Kühtai power plant. A new high-voltage line into the Inn Valley is not necessary. On September 14, anyone interested will have the opportunity to take a look behind the scenes at the power plant construction site.