Wynau power plant

Wynau power plant
View in west direction, photo 1997
location
Coordinates	626 314  /  233936 coordinates: 47 ° 15 '21 "  N , 7 ° 47' 11"  O ; CH1903:  six hundred and twenty-six thousand three hundred and fourteen  /  233936
country	Switzerland  Bern Solothurn
place	Oberwynau
Waters	Aare
Height upstream	400  m above sea level M.
power plant
owner	Onyx Energie Mittelland AG
operator	BKW
Start of planning	1980
Start of operation	1996
technology
Bottleneck performance	10.4 megawatts
Average height of fall	5 m
Expansion flow	220 m³ / s
Standard work capacity	51 million kWh / year
Turbines	1 × tube turbine
Others
was standing	2020

Wynau power plant (until 1992)
On the left machine house with attached boiler house, weir with bottom outlet in the middle and raft ramp on the right. Photo taken around 1925 by Walter Mittelholzer
location
Coordinates	626286  /  233839
Height upstream	410  m above sea level M.
power plant
Start of planning	1891
construction time	14 months
Start of operation	1896
Shutdown	1992
technology
Bottleneck performance	6.4 megawatts
Average height of fall	4.5 m
Expansion flow	200 m³ / s
Standard work capacity	41 million kWh / year
Turbines	4 × Kaplan turbines 2 × Propeler turbines
Others
was standing	2020

The Wynau hydropower plant , also called Wynau I , is a run-of-river power plant on the Aare near Wynau , which was commissioned in 1895. The operator of the system is onyx Energie Mittelland AG . The power plant built in 1891 was replaced by a new one in 1996. The machine house is on the right bank of the Aare, on the left bank is the Schwarzhäusern power plant , which was built in 1921 and uses the same weir . The impoundment and the machine house are located in the canton of Bern , half of the underwater is in Bern and half in Solothurn , because the canton border runs in the middle of the river after the weir.

history

The power plant goes back to the initiative of the businessman Robert Müller-countryman from Lotzwil . In 1891 he bought a piece of land near Oberwynau an der Aare and submitted a planning application for a power station to the governor . The entrepreneur could not carry out the planning and financing himself, which is why he bought the project for 300,000  SFr. sold to Siemens & Halske from Berlin . The German company set up an office in Switzerland on the basis of this order and began building the plant in 1893, which it completed within 14 months. In February 1895, while construction was still going on, the Diskonto-Gesellschaft and Basler Handelsbank founded Elektrizitätswerke Wynau AG, which was supposed to operate the power station. The power plant cost 2.1 million SFr. and went into operation on January 23, 1896. The first customer was the municipality of Langenthal, which used the electricity for street lighting. At the beginning there was not much interest in the new form of energy, so that the plant had difficulties selling electricity. The power station was therefore sold to Langenthal and 27 other communities in Oberaargau as early as 1903 , which guaranteed the purchase of electricity. In 1921 the number of parishes involved rose to 45.

The Wynau power plant was supplemented in the 1920s with the Schwarzhäusern power plant on the other side of the river. The first major renovation took place in the 1930s, and in the 1990s the facility was replaced by a new building with a new weir.

In 2000, Elektrizitätswerke Wynau AG became Onyx Energie Mittelland AG, in which BKW acquired the majority in 2006. Since then it has been run as an independent subsidiary of BKW.

• Power plants near Wynau
• 

  left power plant Schwarzhäuser, right power plant Wynau. Picture taken between 1925 and 1937

• 

  Picture 1997, on the left the new construction of the Wynau power plant, behind it the old headquarters, on the right Schwarzhäusern

technology

First power plant

The power plant uses the gradient between Bannwil and the canton border between Bern and Solothurn . The original weir was 125 m long and blocked the river vertically, creating a 4.5 km long impoundment. It was provided with a raft lane and a fish ladder .

The machine house was located in a bay on the right bank of the river and in 1895 there were five vertical-axis Jonval turbines in its hall . The machines supplied by Rieter produced a combined output of 3000 hp. In 1908 a sixth turbine was installed. The two excitation turbines were arranged between the main turbines in the middle of the machine room.

Machine room in 1899

The turbines drove horizontal-axis generators via bevel gears - an arrangement that was chosen because the construction of high-speed turbines was not yet fully developed. Initially, the turbines had a combined output of 2.2 MW and generated 18 GWh annually. In 1906 a 700 kW steam turbine was installed in an adjoining building , which was used as a reserve in the event of insufficient output or failure of the hydropower plant. The chimney of the boiler house is visible in old pictures .

The output of the power plant was soon no longer sufficient, so that the Schwarzhäusern power plant was built on the left bank of the river between 1921 and 1923 . It uses the same weir system as the Wynau power plant and is equipped with four propeller turbines. The plant had an output of 6.2 MW when it opened .

Over the years, the output of the turbines at the Wynau power plant has increased. By 1926, all Jonval turbines had been replaced by Bell Francis turbines . Five single-stage Francis turbines with an output of 800 hp were in use, and during floods the sixth turbine, a three-stage Francis turbine with an output of 1500 hp, was put into operation.

In 1932 a diesel generator with an output of 2.7 MW was also installed as a thermal reserve .

In 1936 and 1937 the plant was converted to high-speed turbines with umbrella generators and the output of the power plant was increased. There were four Kaplan turbines and two propeller turbines in use, which had been delivered to Ateliers de constructions mécaniques de Vevey (ACMV). The turbines had a combined output of 11,100 hp, the generators could deliver a maximum of 6.8 MW. After the renovation, the average annual production reached 35 GWh.

New building in 1996

The existing plant was shut down in 1992 and replaced by a new one, which went into operation in 1996. The weir was rebuilt and the machine house was integrated into the weir. The six turbines were replaced by a single one with a maximum output of 10.4 MW.

Wynau tunnel project

A further expansion of hydropower in Wynau would be possible through the construction of a 2900 m long tunnel through the Wynauer Feld, which would only return the water to the Aare in Murgenthal . In addition to the already installed turbine, another turbine with a suction capacity of 220 m³ / s would have been installed in the machine house, which would have had an output of 16 MW. This would have increased the plant's standard energy capacity to 139 million kWh per year, which would again significantly increase production.

The environmental associations objected to the construction of this diversion power plant because the Aareknie Wolfwil-Wynau has been listed in the federal inventory of landscapes and natural monuments of national importance since 1996 . In its 2003 decision, the Federal Supreme Court rated the landscape worthy of protection higher than the need to increase electricity production. Nothing about that changed after the Fukushima nuclear disaster some countries decided to phase out nuclear energy. In 2013, BKW rated the further expansion of hydropower as unattractive because of cheap green electricity imported from abroad, so that the CHF 100 million project is not being pursued particularly actively.

Distribution network

The generators generated an output voltage of 450 V at a frequency of 50 Hz. It was increased to 9 kV for transmission in the local networks by air-cooled transformers . In the localities it was stepped down again so that voltages of 125 V, 220 V and 500 V could be made available.

In 1943 the Wynau electricity works supplied an area of ​​494 km², which comprised 62 communities with a total of 71,000 inhabitants. The highest output was 13.8 MW, the annual energy consumption 13.8 GWh.

In addition to the general supply, the power plant also delivered direct current for the 1200V contact line of the Langenthal-Jura-Bahn (LJB), which was generated with a converter system.

Web links

Commons : Kraftwerk Wynau  - collection of pictures, videos and audio files

Individual evidence

1. ↑ ^{a b} Wynau and Schwarzhäusern power plants. onyx Energie Mittelland, accessed on May 16, 2020 . 
2. ↑ Nikiaus Baer: An energetic past . In: Siemens (ed.): Monitor . February 2008, p. 23 ( siemens.ch [PDF; accessed on May 16, 2020]).
3. ↑ Walter Ryser: Insights into a hidden energy world. In: Unter-Emmentaler. Retrieved on May 16, 2020 (German). 
4. ↑ ^{a b c d} W.E. Bossard: Switzerland's hydropower . Ed .: EDA, Department for Water Management. January 1, 1914, p. 39 ( admin.ch ).
5. ↑ R. Hofmann: The propeller turbines of the new Wynau electricity works . 1924, p. 175 , doi : 10.5169 / SEALS-82880 .
6. ↑ ^{a b c d e f g} The Wynau electricity works . In: Bern Week . tape 34 , no. 51 , 1944, doi : 10.5169 / SEALS-649623 .
7. ↑ power plant Wynau the power stations Wnyau A.-G. Langenthal - Plant I (plant on the right) . In: Schweizerischer Wasserwirtschaftsverband (Ed.): Guide through the Swiss water management . tape 1 , 1926, pp. 554 .
8. ^ IUB Engineering (ed.): New Wynau power plant . 1997 ( engineering-group.ch [PDF]).
9. ↑ Stefan Stöcklin: Energy: The tunnel of the impulse. In: Observer. August 12, 2013, accessed May 16, 2020 .