Twelve percent - this was the gradient that the Herrenknecht Gripper TBM had to climp through hard rock for the hydropower project Glendoe.
To produce energy environmentally friendly in the Scottish Highlands, water was dammed up above Loch Ness and led to hydropower plant turbines via a tunnel with a length of almost eight kilometers. The particularly great fall height allows for a high production capacity of the plant - which is able to supply a metropolis with a quarter of a million inhabitants with electricity.
In September 2006, a Herrenknecht Gripper TBM was launched to drive the tailrace tunnel. Along the headrace tunnel section, the TBM is put to the test due to a gradient of approx. twelve percent and an altitude difference of 600 meters. Having achieved continuously high performance rates in hard rock (up to more than 270 meters per week), "Eliza Jane" reaches its target on January 7, 2008.