Kallnach power plant

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Kallnach power plant
Machine house of the plant from 1913
Machine house of the plant from 1913
location
Kallnach power plant (Canton of Bern)
Kallnach power plant
Coordinates 584 012  /  207 838 coordinates: 47 ° 1 '17 "  N , 7 ° 13' 42"  O ; CH1903:  584,012  /  207838
country Switzerland
place Kallnach
Waters Aare
f1
power plant
owner BKW energy
construction time 1909–1913, renewed in 1980
Listed since 1970s (machine house)
technology
Bottleneck performance 1913: 9.7 megawatts

1980: 8 megawatts

Average
height of fall 		20 m
Standard work capacity 51 million kWh / year
Turbines Plant from 1913:
6 double Francis turbines (dismantled)

Plant from 1980:
1 tube turbine

Others
Website BKW AG, Kallach power plant

The Kallnach power plant is a run-of-river power plant that was built between 1909 and 1913 and was renovated in 1980. The water of the Aare is dammed up at Niederried to Niederriedsee and diverted for energy use through a 2100 meter long tunnel to Kallnach , where the height difference of 22 meters is used by an underground bulb turbine . The underwater is led in a straight line through the Grosse Moos through an open three-kilometer-long canal and into the Hagneck Canal near Walperswil . The bulb turbine has an output of 8 MW; the average annual production is 51 GWh. The power plant is owned by BKW Energie .

history

Construction of the first plant

In order to meet the steadily increasing demand for electrical energy at the beginning of the 20th century, BKW decided to build a new power plant to complement the three existing plants in Hagneck , Spiez and Kandergrund .

The foundation for the weir of the Niederried reservoir was made in caisson construction by the company of Conradin Zschokke . The weir was designed for a maximum discharge of 1400 m³ / s, but the power plant only had to guarantee a residual water volume of 7 m³ / s. Because with this small amount of residual water, the water level of the Aare in Aarberg came to be below the inlet of the old Aare, the residual water needed there had to be fed directly from the newly built weir via a 5.2 km long canal. The weir was equipped with a fish ladder , a ship's ramp and a raft channel, although the use of the latter was already questioned when it was opened, as hardly any wood was cut on the Aare at the beginning of the 20th century .

The supply tunnel was excavated by blasting. On the Kallnach side, where the tunnel leads through loose rock, mountain damage occurred in some cases in the form of subsidence on the surface, which had to be backfilled.

At the end of the upper water canal was the valve house, where the three riveted pressure lines began, which led to the machine house, where six double Francis turbines were located. The turbines were supplied by Piccard, Pictet & Cie from Geneva , generators and transformers came from BBC . The two towers of the building served as the exit for the high-voltage cables.

The underwater canal was excavated with a bucket chain excavator , which could move up to 2000 m³ of earth daily.

The total construction costs amounted to 9.3 million Swiss francs.

  • Aerial view of the facility

  • Emblem above the portal

  • Runner of one of the double Francis turbines

  • Underwater channel

business

The power plant went into operation on July 1, 1913. The system initially only supplied electricity at 40 Hz, the standard frequency of the BKW network at the time. Operation with 50 Hz was planned from the beginning so that energy could also be supplied to the network of the Freiburg power plants operated at this frequency . The power plant had a maximum output of 9.7 MW.

In 1921, the entire BKW network at that time was converted to 50 Hz.

In 1950 there was a transformer explosion in the power plant. The oil fire that followed was difficult to put out because the fire brigades did not yet have suitable extinguishing agents . Finally it was possible to smother the fire with a carbon dioxide extinguisher and wet bags.

The plant was in operation until November 14, 1978.

Kallnach power plant (the power plants on the Aare between Bern and Lake Biel)
Red pog.svg
Location map of the power plants between Bern and Lake Biel. The plants to the west of the Wohlensee are operated by BKW.

Renewal of the power plant

The system from 1913 could process a maximum of 60 m³ / s, according to other sources 70 m³ / s, water, an amount that is significantly less than the average runoff of the Aare. For these reasons, it was decided in 1959 to make better use of the river's water, which led to the construction of the two power plants in Aarberg and Niederried-Radelfingen , which were designed to process 170 m³ / s.

Despite the new power plants, BKW did not want to shut down the Kallnach power plant, as in this case the plant would have had to be dismantled. In addition, the underwater channel of the power plant has a significant influence on the groundwater level in the Grosse Moos, so that it would probably have had to continue to operate if it had been shut down.

BKW therefore decided to replace the old system with a new one as cheaply as possible. After the construction of the new power plants on the Aare, the amount of water to be processed could be reduced to 45 m³ / s, so that the six existing turbines could be replaced by a single bulb turbine housed in a new underground machine house with an external generator. The supply tunnel and the underwater canal could be taken over from the old power plant unchanged. The plant went into operation in 1980 and has a concession that expires in 2043.

The new power plant normally only processes 20 m³ / s of water, which is just enough for the proper operation of the underwater canal. The amount of water to be processed in Kallnach is only increased when the flow of the Aare exceeds 190 m³ / s and the power plants on the Aare can no longer process all of the water.

  • Underground engine room

  • Sectional drawing of the new system

See also

Web links

Commons : Kraftwerk Kallnach  - Collection of images, videos and audio files
  • Kallnach hydropower plant. BKW , accessed on May 6, 2015 .
  • Peter Hässig: The Kallnach hydropower plant . In: The Seebutz . Gassmann, Biel 2004, p. 111-120 ( Link [PDF]).
  • Peter Hartmann: The renewal of the Kallnach power plant . In: VAW Mitteilungen . No. 34 . Zurich 1979, p. 139–146 ( Link [PDF; accessed on May 3, 2015]).
  • La nouvelle centrale des Forces motrices bernoises, près de Kallnach . In: Bulletin technique de la Suisse romande . tape 40 , no. 6 , 1914, pp. 61-67 , doi : 10.5169 / seals-30842 (French).

Individual evidence

  1. ↑ Ulrich Jampen: When electricity came to Zealand . In: The Seebutz . Gassmann, Biel 2003, p. 85-92 ( Link [PDF]).