Manapouri Power Station
Manapōuri Power Station | ||
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Annual generation 5100 GWh[2] | | |
b Lake Manapōuri is a natural lake - the drop between it and the sea is used by Manapōuri station. ^c The former figure is based on the installed capacity of 854 MW, while the latter figure is based on the resource consent limited capacity of 800 MW |
Manapōuri Power Station is an
Completed in 1971, Manapōuri was built primarily to supply electricity for the
Since April 1999, the power station has been owned and operated by
Construction
The power station machine hall was excavated from solid granite rock 200 metres below the level of Lake Manapōuri. Two tailrace tunnels take the water that passes through the power station to
Access to the power station is via a two-kilometre vehicle-access tunnel which spirals down from the surface, or a lift that drops 193 metres (633 ft) down from the control room above the lake. There is no road access into the site; a regular boat service ferries power station workers in 35 km across the lake from Pearl Harbour, located in the town of Manapouri at the southeast corner of the lake.
This same access was for many years used to ferry tourists for public tours of the site, but since 2018 maintenance work by Meridian Energy means tours are closed "for an indefinite period".[4]
The original construction of the power station cost
Soon after the power station began generating at full capacity in 1972, engineers confirmed a design problem. Greater than anticipated friction between the water and the tailrace tunnel walls meant reduced
History
Early history
The first surveyors mapping out this corner of New Zealand noted the potential for hydro generation in the 178-metre drop from the lake to the
In January 1926, a Wellington-based syndicate of ten businessmen headed by Joseph Orchiston and Arthur Leigh Hunt, New Zealand Sounds Hydro-Electric Concessions Limited, was granted by the government via an Order in Council the rights to develop the waters which discharged into Deep Cove, Doubtful Sound, and the waters of Lake Manapōuri, to generate in total some 300,000 horsepower (220,000 kW). The company attempted to attract Australian, British and American finance to develop the project, which would have required the construction of a powerhouse and factory complex in Deep Cove, with accommodation for an estimated 2,000 workers and wharf facilities, with the complex producing atmospheric nitrogen in the form of fertiliser and munitions. Various attempts to finance the scheme were not successful, with the water rights lapsing and the company fading into obscurity by the 1950s.
In 1955 the modern history of Manapōuri starts, when
Construction history
- February 1963, Bechtel Pacific Corporationwon the design and supervision contract.
- July 1963, Utah Construction and Mining Company and two local firms won contracts to construct the tailrace tunnel and Wilmot Pass road. Utah Construction also won the powerhouse contract.
- August 1963, Doubtful Soundto be used as a hostel for workers building the tailrace tunnel. During the 1930s she was a top-rated trans-Tasman passenger liner, with accommodation for 304 first-class passengers. She continued to serve as a hostel until December 1969.
- February 1964, tailrace-tunnel construction began.
- December 1967, powerhouse construction was completed.
- October 1968, tunnel breakthrough.
- 14 September 1969, the first water flowed through the power station.
- September/October 1969, commissioning of the first four generators.
- August/September 1971, the remaining three generators were commissioned.
- 1972, the station was commissioned. It was then that engineers confirmed the limitations of peak capacity due to excess friction in the tailrace tunnel.
- June 1997, construction work by a Dillingham Construction / Fletcher Construction / Ilbau joint venture began on the second tailrace tunnel.
- 1998, the Robbins Deep Coveend of the tunnel.
- 2001, tunnel breakthrough.
- 2002, the second tunnel was commissioned. A $98 million mid-life refurbishment of the seven generator units begins, with the goal of raising their eventual output to 135 MVA (121.5 MW) each. By June 2006, four generating units had been upgraded, and the project was on schedule for completion in August 2007.[7] By the end of 2007, all seven turbines had been upgraded.[8]
- 2014, three transformers were replaced following the discovery of an issue with the oil cooler on one of Manapōuri's seven transformers during maintenance in March. The first removed transformer was the largest pieces of hardware to leave the station since its completion. The three transformers were replaced with newly manufactured ones, delivered via Wilmot Pass between December 2014 and February 2015.[9]
Political history
In July 1956, the New Zealand Electricity Department announced the possibility of a project using the Manapōuri water, an underground power station and underground tailrace tunnel discharging the water at Deep Cove in
On 2 May 1961
In 1963, Consolidated Zinc/Comalco decided it could not afford to build the power station. The New Zealand government took over. Electricity generated by the plant was sold to Consolidated Zinc/Comalco at under an arrangement designed to return the cost of building the power station to the government.
In 1969, Consolidated Zinc's electric power rights were transferred to Comalco Power (NZ) Ltd, a subsidiary of the Australian-based
In 1970, the
In 1972, New Zealand elected a new Labour government. In 1973, the Prime Minister,
In 1984, the
On 1 April 1999 - the 1998 reform of the New Zealand electricity sector took effect: the Electricity Corporation of New Zealand was broken up and Manapōuri was transferred to new state-owned generator Meridian Energy.
In 2002, the Government rejected an application of a business, Southland Water 2000, to bottle 40,000 cubic metres of water in 20 hours, twelve times a year, before the water from the power station is released into Doubtful Sound.[11]
In July 2020,
Specifications and statistics
Power station
Average annual energy output | 4800 GW·h |
Station generating output | 850 MW |
Number of generating units | 7 |
Net head | 166 m |
Maximum tailrace discharge | 510 m3/s |
Turbines | 7 × vertical Francis type, 250 rpm, 121.5 MW made by General Electric Canada International Inc. |
Generators | 7 × 13.8 kV, 121.5 MW / 135 MVA (5648 A), made by Siemens Aktiengesellschaft (Germany). |
Transformers | 8 × 13.8 kV/220 kV, rated at 135 MVA, made by Savigliano (Italy) 1 Transformer is kept as a spare unit.. |
Civil engineering
Machine hall | 111 m length, 18 m width, 34 m height |
First tailrace tunnel | 9817 m, 9.2 m diameter |
Second tailrace tunnel | 9829 m, 10.05 m diameter |
Road access tunnel | 2,042 m, 6.7 m wide |
Cable shafts | 7 × 1.83 m diameter, 239 m deep. |
Lift shaft | 193 m |
Penstocks | 7 × 180 m long |
Operation
The massive inertia of the column of water in the long tailrace tunnel makes rapid changes to Manapōuri's generation difficult. Further, because the tailrace tunnel emerges at sea level in Deep Cove, power production can be influenced by the state of the tide there. The maximum tidal range is 2·3 metres (7'8") which is a little over one percent of the station's head. The plot shows a variation of about 5MW linked not to the usual twenty-four-hour cycle of electricity usage but to the times of high and low tide, which cycle around the clock.
Transmission
Manapōuri is connected to the rest of the National Grid via two double-circuit 220 kV transmission lines. One line connects Manapōuri to Tiwai Point via North Makarewa substation, north of Invercargill, while the other line connects Manapōuri to Invercargill substation, with one circuit also connecting to North Makarewa substation. Another double-circuit 220 kV line connects Invercargill to Tiwai Point.[16]
If Tiwai Point reduced demand or closed, Manapōuri generation would have to be reduced to prevent overloading the transmission lines out of the lower South Island. The Clutha Upper Waitaki Lines Project (CULWP) is under construction as of September 2021[update] to relieve this constraint, allowing an extra 400 megawatts to be sent north.[17][18]
References
Bibliography
- Fox, Aaron P.,The Power Game: the development of the Manapouri-Tiwai Point electro-industrial complex, 1904-1969 PhD Thesis, University of Otago, Dunedin, (2001) http://otago.ourarchive.ac.nz/handle/10523/335
- Peat, Neville. Manapouri Saved!: New Zealand's first great conservation success story: integrating nature conservation with hydro-electric development of Lakes Manapouri and Te Anau, Fiordland National Park Longacre Press, Dunedin (1994)
- Integrating Nature Conservation with Hydro-Electric Development: Conflict Resolution with Lakes Manapouri and Te Anau, Fiordland National Park, New Zealand - Mark, Alan; professor, environmentalist, member of the 'Guardians of Lake Manapouri' institution
- Manapouri - the Toughest Tunnel, a 60-minute television documentary made in 2002 by NHNZ
Notes
- ^ a b c d e f g h "Manapouri Facts and Figures - Meridian Energy". Archived from the original on 14 January 2015. Retrieved 4 September 2011.
- ^ "List of Generating Stations November 2010 - New Zealand Electricity Authority". Archived from the original on 2011-07-24. Retrieved 2011-01-25.
- ^ "Energy Data File". Ministry of Economic Development. 1 July 2010. Archived from the original on 12 April 2011. Retrieved 23 January 2011.
- ^ "Manapouri Underground Power Station". Archived from the original on 10 December 2017. Retrieved 5 August 2019.
- ^ "New Zealand CPI Inflation Calculator - Reserve Bank on New Zealand". Archived from the original on 1 July 2010. Retrieved 25 November 2013.
- ^ "Power From Manapouri - Construction Brochure". Archived from the original on 2 October 2016. Retrieved 30 September 2016.
- ^ "Annual Report 2006" (PDF). Meridian Energy. June 2006. Archived from the original (PDF) on 2008-10-16. Retrieved 2007-10-04.
- ^ "Refurbishment: Upgrading Turbines at Manapouri". 7 Jan 2008. Archived from the original on 2016-11-07. Retrieved 2016-11-07.
- ^ Brittany Pickett (23 December 2014). "New transformers for Manapouri station". The Southland Times. Archived from the original on 2017-09-01. Retrieved 2016-11-07.
- ^ "Manapouri - te Anau Development Act 1963 No 23 (As at 30 June 2012), Public Act Schedule Agreement dated 15 August 1963 – New Zealand Legislation". Archived from the original on 5 December 2019. Retrieved 5 December 2019.
- ^ NZ Herald, "Fiordland water export scheme rejected", 8 April 2002, https://www.nzherald.co.nz/nz/fiordland-water-export-scheme-rejected/XQINOW24PDBE7BND7LXUXE4OUQ/ Archived 2022-04-18 at the Wayback Machine
- ^ Rutherford, Hamish (9 July 2020). "Rio Tinto announces plans to close New Zealand aluminium smelter in 2021". NZ Herald. Archived from the original on 2020-07-09. Retrieved 2020-08-20.
- ^ Braae, Alex (10 July 2020). "The Bulletin: Tiwai Point closing affects everything". The Spinoff. Archived from the original on 2020-08-21. Retrieved 2020-08-20.
- ^ "Ambitious proposals for surplus electricity once Tiwai closes". Radio New Zealand. 10 August 2020. Archived from the original on 2023-06-04. Retrieved 2020-08-20.
- ^ "UPDATE 2-Rio Tinto reaches deal to continue NZ aluminium smelter ops till 2024". Reuters. 2021-01-13. Archived from the original on 2021-01-14. Retrieved 2021-03-02.
- ^ "Otago-Southland Regional Plan - 2012 Annual Planning Report" (PDF). Transpower New Zealand Limited. Retrieved 1 January 2011.
- ^ "'Surplus' power from smelter could be freed-up for South Island in 2022". Stuff. 2019-12-02. Archived from the original on 2021-09-29. Retrieved 2021-09-29.
- ^ Morgan, Jared (2021-01-09). "Transmission line upgrade next phase starts". Otago Daily Times Online News. Archived from the original on 2021-06-21. Retrieved 2021-09-29.
External links
- [1] Power station info page from Meridian Energy