After the end of the work, the metal rods of the valve gate were removed again. © Stadtwerke Tölz
The two turbines in the Isar power plant in Bad Tölz produce renewable electricity. After an extensive renovation, this now works even better.
Bad Tölz – The Isar power plant at the Tölz reservoir has been producing electricity for almost exactly 65 years. On May 28, 1958, after a good year and a half of construction, it was put into operation. Since then, it has been reliably generating renewable energy for the region day after day with its two turbines. With around 10 million kilowatt hours of electricity per year – enough for around 3500 households – it makes a significant contribution to the local energy transition. To ensure that this output is maintained for a long time to come, the heart of the power plant – the two turbines – has been undergoing major maintenance since summer 2022. According to the Tölzer Stadtwerke, this has now been completed.
"Electricity yield noticeably increased with the same amount of water"
As a rule, around 15,000 litres of water per second flow through each turbine. In order for the specialist company to be able to carry out the necessary replacement and cleaning work, the area must first be drained. "A crane and a professional diver set a so-called valve gate in order to be able to reach the components that are under water during normal operation," explains municipal utility press spokeswoman Martina Geisberger on request. Metal rod by metal rod – also known as a needle – is lifted into the water by the crane and anchored in a rail by the diver under water. At the end, the rods lined up next to each other form the needle gate. This is set on both the upper and the underwater side, thus draining the area between the barriers.
The municipal utilities used this not only for work on the turbines, but also for improving the concrete foundation, switching to biological – and thus degradable – machine grease and restoring the old Isar profile. "In this latter measure, the original head of 1957 was regenerated by the removal of the alluvial gravel, and immediately the electricity yield could be noticeably increased with the same amount of water," says Geisberger.
Power plant turbines in Bad Tölz refurbished
The estimated costs amount to around 300,000 euros per turbine – "money well invested, assuming that the Isar power plant will continue to reliably supply the region with clean hydropower for decades to come".
If you would like to get an idea of the interior of the hydroelectric power plant, you will have the opportunity to do so on Friday, 14 July, at the "Day of the Hydroelectric Power Plant". More information will follow soon.
You can find even more up-to-date news from the region at Merkur.de/Bad Tölz.