Töging am Inn – stream from the river – Bavaria

It’s the quietest up here in the moated castle. But if on Tuesday these gears with the red and black gears start to crunch one after the other and let a few meters of wire rope off the coils, if because of that the slides lower one after the other in front of the inlets, then will one generator after the other also leaked down in the power house. After almost 100 years of industrial history, it will be very quiet in the long-standing listed hydropower plant in Töging am Inn. And then at the latest, says Bernhard Gerauer, “every second counts”.

Because when the Tögingen power plant goes offline this Tuesday, the 15 large, rigidly constructed Francis turbines will have done their job forever. Just a stone’s throw away, however, three new machine sets are due to start up next spring, this time driven by three huge Kaplan turbines, on which the blades of the screws can be adjusted. In this way, depending on the water supply, its speed can be regulated much more easily to the speed required to keep the frequency of 50 Hertz in the power grid. Because of these much more efficient turbines, among other things, the Tögingen Inn power plant will be able to produce around 700 gigawatt hours of electricity per year after the ongoing renovation, 140 gigawatt hours more than before and enough for 200,000 average Bavarian households. This 20 percent increase alone already exceeds the amount of electricity that the 2200 smallest hydropower plants in Bavaria produce each year.

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And electricity is needed in Bavaria, especially when it is regenerative. The electricity yield from hydropower is expected to increase from 12.5 to 13.5 terawatt hours by 2022, Minister for Economic Affairs Hubert Aiwanger announced two years ago in a government declaration on the energy transition. The conversion in Töging alone will bring 14 percent of this additional terawatt hour. But because it is by far the largest hydropower project in all of Germany at the moment, the state government will once again clearly miss the expansion target that has been pulled out of the drawer at regular intervals.

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At least that shouldn’t fail with Bernhard Gerauer. He is project manager for Töging at the Austrian Verbund AG. It had taken over the Bavarian Inn power plants from the Eon Group in 2009, and in 2013 the border power plants on the Inn were added in exchange for their own business in Turkey, which until then had belonged to Verbund and Eon each half. There are a total of 21 plants including the Danube power plant in Jochenstein east of Passau. In Töging, in the Altötting district and around 20 kilometers as the crow flies from the border, the association commissioned the first study for the 250 million euro renovation in 2011. Gerauer has been a project manager since 2014. Now, two years after the foundation stone was laid for the new power plant, he can already check whether the first turbine is properly seated. It measures 4.30 meters in diameter and you can see the gap to its concrete and steel shell. “It’s a matter of tenths of a millimeter,” says Gerauer, because such a turbine shouldn’t jam when 136 cubic meters of water per second shoot through this pitch-dark shaft with tremendous pressure, just like through the two shafts next door. In the inlets, the workers still climb over scaffolding and look very small in relation to the huge concrete structure.

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But there shouldn’t be much of all of this in the coming year. Already now, heavy dump trucks drive up almost every minute in order to recreate the overburden stored nearby from the deep excavation pit. Because the new power plant is being built right next to the old one, where there used to be a kind of overflow for emergencies. A wide concrete strip will peek out from above and below, the rest will be backfilled with earth and greened in order not to compete with the industrial monument next door, which is still buzzing in front of it until Tuesday.

The power plant in Töging is the oldest on the Inn and not just a core of industrialization in southeastern Upper Bavaria. It is also the nucleus of the city of Töging, which has two red flashes of blue waves in its coat of arms and, until 100 years ago, was little more than a loose collection of farms. But then the newly founded “Innwerk, Bayerische Aluminum AG” had a factory built in Töging from 1919 to 1924 and a power station for this factory, because enormous amounts of direct current are required for electrolysis in the production of aluminum.

It was only since aluminum production in Töging was stopped in the mid-1990s that the power plant only produced alternating current for the general energy supply. Six of the 15 generators have always done this, eight have been converted for this purpose, and one has been shut down. If the power station is to come to a complete standstill soon, the question will also arise of how the monument could be used in the future. There are “processes”, says Verbund spokesman Wolfgang Syrowatka, but it should definitely be something that does justice to the importance of the power plant for the company and for the city. Something other than a cultural use, for example as a combined energy and city museum, is hardly an option.

But a lot is still needed anyway, because the entire system, and thus also the construction site, actually stretches over almost 30 kilometers. In Jettenbach near Waldkraiburg, a weir guides most of the water from the Inn into the Inn Canal. While the river meanders through the landscape around 30 kilometers further to Töging, the canal is around ten kilometers shorter, has much less gradient and thus creates the necessary height in Töging. Such a construction with a canal is called “diversion power plant”. A plant of this size would certainly no longer be feasible 100 years after it was built, says Bernhard Gerauer. But the power plant is already there. And it remains, just much newer.