A new penstock has been installed for the extension of the Tierfehd hydroelectric power plant, which generates 261 MW and is located in the Linth valley of the Swiss canton Glarus. In addition, a new bifurcation had to be integrated to the existing penstock with a heigth of 1,200 m. Due to this extension the power plant Tierfehd tranforms to a pumped-storage hydroelectricity. Now it is possible to produce valuable peak load energy.

An excellent weldability was a major condition to the successful assembly of the new penstock and the bifurcation. For these, fine-grained thermomecanically rolled structural steels of the DI-MC 355 and 460 types were used, with thicknesses going from 15 to 120 mm. For the sickle plate of the bifurcation, the high-strength fine grained structural steel Dillimax 690 was used. It had a thickness of 210 mm with additional through-thickness properties (Z35).