Mühltal hydropower plant

Mühltal hydropower plant
location
Coordinates	47 ° 59 '46 "  N , 11 ° 29' 6"  E Coordinates: 47 ° 59 '46 "  N , 11 ° 29' 6"  E
country	Germany Bavaria
place	Straßlach-Dingharting
Waters	Mühltalkanal ( Isar )
power plant
owner	Uniper power plants
operator	Uniper power plants
construction time	1920-1924
Start of operation	1924
technology
Bottleneck performance	11.2 megawatts
Expansion flow	80 m³ / s
Standard work capacity	70 million kWh / year
Turbines	3 Francis turbines
Generators	3 alternators
Others

The Mühltal power plant is a run-of-river power plant on the Isar . The power plant, which opened in 1924, is located west of Straßlach in the Upper Bavarian district of Munich . The electrical output of the power plant is 11.2 MW. The operator of the power plant has been Uniper Kraftwerke GmbH since 2016 .

location

The power plant is not located directly on the Isar, but is supplied with water via the Mühltalkanal, which is discharged from the Isar around 7.3 km above the power plant at the Ickinger Wehr and flows back into the Isar around 2 km below the power plant. A maximum of 90 m³ / s of water can flow through the canal to the power plant, which has a gradient of 17.4 m.

technology

The power plant consists of the so-called computer house, an intake structure with a rake to remove coarse dirt and nine barrier gates, the machine hall arranged in parallel behind it and the switch hall with a clock tower at right angles to it. Next to the computer house there are two large gates in front of the empty shot, with which the water can be directed past the power plant, as well as the entrance to the raft slide.

In the machine hall there are three large ones made by Escher, Wyss & Cie. Francis turbines made in Ravensburg with a vertical shaft and three-phase alternators from Brown, Boveri & Cie. The electrical power they generate with a voltage of 5,000 V is converted to 20,000 V by a group of three transformers in front of the south side of the power plant and fed into the power grid of the distribution network operator E.ON Bayern . Around 70 million kWh (70 GWh) of electricity are generated annually, which supplies around 17,500 households.

Architecture and art

The power plant buildings in the style of reduced classicism are under monument protection.

On the ceiling of the switching hall there is a ceiling painting by Gottlob Gottfried Klemm (1871–1955), a pupil of Franz von Stuck . It depicts a compass rose with the cardinal points and four figures from Greek mythology , namely the lightning-throwing father of gods Zeus , the sea god Poseidon , the lord of the winds Aiolos and the sun god Helios . They symbolize power, water, energy generation and distribution.

Transport links

At the end of the road leading from Straßlach into the Mühltal and the local Gasthof Mühltal, the Werksstraße bridges the Floßgasse and the Leerschuss and leads under the connecting passage between the machine house and the switching hall, along the undercurrent facade of the machine hall, over the three large arches of the water outlet to the south side of the power plant. The works street is freely usable for pedestrians and cyclists.

history

The power plant, including the Ickinger weir and the Mühltalkanal, was built by Isarwerke AG as Headquarters III between 1920 and 1924 . This company was founded by the Munich building contractor Jakob Heilmann , the bank Merck Finck & Co and Georg von Simson , partner of the Danat-Bank - Darmstädter und Nationalbank , under the management of his friend Wilhelm von Finck , for the construction and operation of the power plant been. The founders had been associated with their Isarwerke GmbH for a long time in the construction and operation of the Höllriegelskreuth and Pullach an der Isar hydropower plants . The Mühltal project was carried out under the direction of state building officer Franz Langlotz .

Except for an optimization of the turbines in 1936, the machines are still largely in their original condition. The control systems have been modernized again and again over the course of time up to the current remote control from Landshut.

In 1996/97, extensive renovation work was carried out on the decommissioned power plant, the Ickinger weir and the emptied sewer, which cost around 24 million euros.

The ceiling painting in the switching hall, which was painted over in the 1950s, was exposed and restored in the course of this renovation.

Water law permit and river ecology

In the 1990s, the water law permit for the diversion of Isar water into the canal was to be renewed. A broad alliance of nature conservation associations together with the fishing association, the Isar Valley Association and other partners campaigned to guarantee an increased amount of residual water in the natural river bed in order to give the Isar the dynamism of a wild river again. After long negotiations, a new permit was issued in 1998. It stipulated a residual water volume of 15 m³ / s and demanded an extensive renaturation of the river bed. For this purpose, the bank reinforcement from river blocks was removed on one side over a length of 7 km so that the Isar could freely develop into the neighboring alluvial forest . When the bed was moved, new gravel banks were created, on which some natural willow growth took place, so that a new softwood floodplain was created. The Ickingen weir received a new fish passage to increase the passage for fish, the debris from the canal has since been fed to the Isar as material for the construction of one's own bed. Visitor information and a nature trail have also been created at the power plant. The total cost of the measures implemented between 1999 and 2002 was around 3 million euros and was borne by the power plant operator.

Beyond the direct effects on the Isar, the construction measures in the area of ​​the power plant are considered a pilot project for the development of the Isar river system, for which development goals and a catalog of measures were drawn up in the following years. And they motivated politicians in Munich below to pursue the Isar plan there with the extensive renaturation of the river in the southern part of the city. Criticism of individual measures comes from the nature conservationists involved, for example, when the bank fortifications were dismantled, a new wedge-shaped fortification was created below the power plant, which leads to the undesirable deepening of the river bed. Apart from that, a near-natural river dynamic has developed, which redesigns the bed especially during floods . The open gravel areas have increased, the renatured Isar in the Mühltal area is described as a “largely natural river landscape”.

Raft slide

The use of the Isar to generate electricity fundamentally changed the rafting , which was already severely affected by the construction of the Walchensee power plant with its Isar transition . So that it does not come to a complete standstill, a raft slide was installed at the Mühltal power station - as well as at the other power stations on the Isar - which, at 345 m in length, is the longest raft slide in Europe. It has a gradient of initially 9%, which then decreases over 7% to a constant 5%. Their use is regulated by a traffic light . Usually enough water flows through it to keep the slide wet. For the rafts, the flow is increased.

For many tourists on the excursion rafts that run from Wolfratshausen to Munich , the rapid passage with a surge of spray in front of and on the front raft is one of the highlights of the excursion.

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  Raft slide at the Mühltal power station

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  The area from the south

Web links

Commons : Kraftwerk Mühltal  - Collection of images, videos and audio files

Individual evidence

1. ↑ Locations ( Memento from December 5, 2014 in the Internet Archive )
2. ↑ ^{a b c d e} Information board in front of the power plant
3. ↑ Federal Network Agency power plant list (nationwide; all network and transformer levels) as of July 2nd, 2012. ( Microsoft Excel file, 1.6 MiB) Archived from the original on July 22, 2012 ; Retrieved July 21, 2012 . 
4. ↑ Monument Viewer
5. ↑ Tom Soyer: Electrifying Gesamtkunstwerk , Süddeutsche Zeitung from 9./10. July 2011
6. ↑ ^{a b} Nico Döring: A tentative start and the music begins - The Isarplan in Munich: interim balance . In: Ralf Sartori : Die Neue Isar - Das Buch zum Isarplan, Part 2 , Buch & media, Munich 2012 (excerpts from the preprint online )
7. ^ ^{A b} Walter Binder: The redesign of the Isar in the south of Munich . In: Wasserwirtschaft, issue 3/2010. Pages 15-19
8. ^ Bavarian State Office for Water Management, Bavarian State Office for Environmental Protection: Isar River Landscape - from the state border to Landshut . 2001, ISBN 3-930253-85-2