Pumped storage power plants are a technology that has been used for energy storage for over 100 years. In view of the energy transition, they are once again coming into focus as they offer a flexible and sustainable solution for the power supply. EnBW is actively promoting this expansion and has commissioned PORR Tunnelling with the conversion of the Rudolf-Fettweis plant.
Breakthrough achieved
On 13 January 2025, a decisive milestone in the construction phase was reached: the energy diversion tunnel is now fully connected to the cavern. The advance of the energy diversion tunnel towards the cavern began on 10 August 2024 at the junction with the access tunnel. Since 2 January 2025, work has also been carried out in the opposite direction from the cavern to create the connection. The last two metres of rock were removed by a targeted explosion. The energy discharge tunnel is now fully connected to the cavern.
Next steps on the road to completion
In addition to the energy diversion tunnel, the PORR tunnelling team is currently working on the advance of the side tunnels. The formwork, reinforcement and concreting work for the crane runway beams in the cavern will also be completed by February 2025. A further key step is the excavation of the cavern at depth, which is considered the next milestone for the project.
PORR's special civil engineering division is also currently involved. In the cavern crown, a back-anchoring system is being constructed for the crane runway, as well as for the support of the cavern and power plant ceiling. The special civil engineering team is installing 52 four-strand permanent anchors with double corrosion protection here.
The aim is to start operating the pumped-storage power plant by 2027, thereby making an important contribution to the energy transition.
