Mishap delays start of new ÖBB power plant by years

The commissioning of the ÖBB Tauernmoos pumped-storage power plant in the Stubachtal Valley in the Hohe Tauern Mountains, scheduled for the end of 2025, has been delayed until summer 2028. As the "Salzburger Nachrichten" reported on Tuesday, two key components are not fitting. The two turbine spirals, each weighing 35 tons, must be rebuilt by the US manufacturer. ÖBB did not disclose the cause of the mishap, but it is understood to be due to a manufacturing defect.

The spirals resemble snail shells and connect the headrace tunnels to the turbines. The custom-made structures are almost eight meters in diameter and are designed to evenly direct up to 40,000 liters of water per second, flowing from the tunnels at high pressure, onto the turbines. The huge spirals were delivered in sections last year and were now to be welded together in the power plant cavern.

Turbine spirals should last 100 years

As ÖBB spokesperson Robert Mosser confirmed to APA, it was discovered during assembly that the shape of the spirals did not fit perfectly. "Therefore, an agreement was made with the manufacturer to have both components remanufactured." The spirals must withstand enormous loads and are designed to last 100 years. Because they are encased in concrete, any subsequent repair would have involved enormous effort and considerable expense. The extent of the additional costs for ÖBB due to the error is currently being investigated. The fact is that the turbines cannot be installed in the underground machine cavern until the spirals have been installed.

The Tauernmoos pumped storage power plant expands the existing Stubachtal power plant group, where ÖBB generates approximately one-fifth of Austria's traction current. For the power plant, the Tauernmoos Lake and the Weißsee Lake, located 220 meters higher, will be connected by tunnels. In the future, it will cover peak loads in the traction power grid during periods of high electricity demand and generate up to 460 GWh of electricity per year. Construction work has been underway since 2020. The estimated construction costs are approximately €360 million, which ÖBB is financing from its own resources outside of the framework plan.

APA