A milestone was reached in mid-May with the official start of tunnelling at the Murgwerk access tunnel, a key step in the comprehensive conversion project. The breakthrough of the energy discharge tunnel to the cavern and the completion of the crane runway beam had already been successfully completed in advance.

However, to ensure that the pumped storage power plant can go into operation in 2027, work on the Schwarzenbach plant is continuing in parallel. Following completion of the driving work on the access tunnel and the throttle valve chamber there, the team is preparing work on the 350-metre-deep shaft. The pilot drilling began at the end of June. This relatively narrow bore has a diameter of around 35 centimetres. It is being drilled using precise measuring instruments and will serve to prepare for the subsequent widening of the shaft. The shaft foot cavern was reached in less than two weeks. To widen the shaft to a diameter of around 3.10 metres, the PORR Tunnelbau team is mounting an 11-tonne reamer (drill head) on the drill string. Michelle Büber, project manager at EnBW, is sponsoring the shaft.

Work is also progressing at full speed in the cavern: blasting is proceeding according to plan, and the dome as well as benches 1 and 2 have already been completely excavated. With the advance of bench 3 in the cavern section of the Schwarzenbach plant, the next significant section is now imminent.

Thanks to this progress, the conversion of the Rudolf-Fettweis plant remains on schedule. The new pumped storage power plant will make a decisive contribution to the flexibility of the electricity supply and the stability of the power grid.