Mangahao Power Station

When commissioned, Mangahao Power Station had cost £1,493,456,{{Cite web|date=1925|title=AtoJs Online — Appendix to the Journals of the House of Representatives — 1925 Session I — D-01 PUBLIC WORKS STATEMENT BY THE HON. J. G. COATES, MINISTER OF PUBLIC WORKS.|url=https://atojs.natlib.govt.nz/cgi-bin/atojs?a=d&cl=search&d=AJHR1925-I.2.2.3.1&srpos=20&e=-------100--1---bySH---0-AJHR_1925_I_CZz-E-|access-date=2021-03-10|website=atojs.natlib.govt.nz|language=en-NZ}} caused the deaths of 8 tunnellers from carbon monoxide poisoning,{{Cite web|last=|first=|date=4 Jul 1922|title=Terrible Tunnel Tragedy At Mangahao Works SHANNON NEWS|url=https://paperspast.natlib.govt.nz/newspapers/SNEWS19220704.2.12|archive-url=|archive-date=|access-date=2021-01-24|website=paperspast.natlib.govt.nz}} an explosion{{Cite web|last=|first=|date=3 Aug 1921|title=FATALITY AT MANGAHAO. MANAWATU STANDARD|url=https://paperspast.natlib.govt.nz/newspapers/MS19210803.2.63|archive-url=|archive-date=|access-date=2021-01-24|website=paperspast.natlib.govt.nz}} and crushing,{{Cite web|last=|first=|date=30 Aug 1923|title=TUNNEL FATALITY. AUCKLAND STAR|url=https://paperspast.natlib.govt.nz/newspapers/AS19230830.2.94|archive-url=|archive-date=|access-date=2021-01-24|website=paperspast.natlib.govt.nz}} and was the main power station serving the lower North Island, with transmission lines connecting Mangahao with Wellington, Palmerston North, Whanganui, Masterton, Napier and Hastings. The power station was connected through to the Waikaremoana hydro scheme in 1929 and through to Arapuni Dam in 1934, forming the basis of the North Island transmission grid.

Mangahao was officially opened by the Prime Minister, William Massey, on 3 November 1924. It was one of his last public duties before he died. Supply expanded as transmission equipment was built:{{Cite web|date=1926|title=AtoJs Online — Appendix to the Journals of the House of Representatives — 1926 Session I — D-01 PUBLIC WORKS STATEMENT (BY THE HON. K. S. WILLIAMS, MINISTER OF PUBLIC WORKS).|url=https://atojs.natlib.govt.nz/cgi-bin/atojs?a=d&d=AJHR1926-I.2.2.2.1&pg=101&e=-------100--1---bySH---0-AJHR_1926_I_DZz-I-|access-date=2021-03-10|website=atojs.natlib.govt.nz|language=en-NZ}}

• 3 November 1924: {{Convert|3|mi||abbr=on}} 11 kV line to Shannon to supply the Horowhenua Power Board, replacing a steam plant.
• 19 December 1924: Mangahao-Bunnythorpe 110 kV west line, temporarily operating at 11 kV, to supply Manawatu-Oroua Power Board and Palmerston North Borough Council.
• 24 December 1924 (full supply 10 March 1925): Mangahao-Khandallah 110 kV east and west lines, Khandallah substation, and Khandallah-Petone 11kV line to supply Hutt Valley Power Board.
• 26 March 1925: Supply from Khandallah substation to Wellington City Council for testing. Their Evans Bay steam plant assisted with peak-reduction and supplied some power back to Khandallah substation.
• March 1925: Mangahao-Bunnythorpe 110 kV east line and Bunnythorpe substation, giving full supply to Manawatu-Oroua Power Board.
• 6 April 1925: Bunnythorpe-Woodville 110 kV line and Woodville switching station.
• 7 April 1925: Woodville-Mangamaire 110 kV line and Mangamaire substation to supply the Tararua Power Board
• 17 May 1925: Mangamaire-Masterton 110 kV line and Masterton substation to supply the Wairarapa Power Board
• 19 May 1925: Woodville-Dannevirke line 110kV line and Dannevirke substation to supply the Dannevirke Power Board
• 26 August 1925: Khandallah-Ngauranga 11 kV line to supply the Wellington Meat Export Company.
• 14 September 1925: Dannevirke-Waipukurau 110 kV line and Waipukurau substation to supply the Central Hawke's Bay Power Board
• 23 April 1926: Bunnythorpe-Wanganui 110 kV line and Wanganui substation to supply the Wanganui-Rangitikei Power Board
• 8 April 1927: Waipukurau-Napier 110kV line and Napier substation to supply the Hawke's Bay Power Board.{{Cite web|date=1927|title=AtoJs Online — Appendix to the Journals of the House of Representatives — 1927 Session I — D-01 PUBLIC WORKS STATEMENT (BY THE HON. K. S. WILLIAMS, MINISTER OF PUBLIC WORKS).|url=https://atojs.natlib.govt.nz/cgi-bin/atojs?a=d&d=AJHR1927-I.2.2.3.1&pg=101&e=-------100--1---bySH---0-AJHR_1927_I_CZz-G-|access-date=2021-03-10|website=atojs.natlib.govt.nz|language=en-NZ}}

The scheme was first considered by Peter Seton Hay and developed by Frederick Kissel. Earthquake strengthening was done in 1983 and 2015.{{Cite web|last=|first=|date=|title=Mangahao Hydroelectric Power Station|url=https://www.heritage.org.nz/the-list/details/4066|archive-url=|archive-date=|access-date=2021-01-24|website=www.heritage.org.nz}} In 2004{{Cite web|last=|first=|date=26 January 2012|title=2011 NZ Generation Data Update|url=https://www.mbie.govt.nz/assets/98fa09efab/2011-nz-generation-data-update-v006a.pdf|archive-url=|archive-date=|access-date=|website=Ministry of Economic Development}} the original two smaller generating sets were replaced by a {{Convert|26|MW||abbr=on}} Francis turbine unit and, with upgrades, the station capacity is now {{Convert|38|MW||abbr=on}}.

{{Reflist}}

• {{cite book | editor=Martin, John E | title=People, Power and Power Stations: Electric Power Generation in New Zealand 1880 – 1990| location=Wellington| publisher=Bridget Williams Books Ltd and Electricity Corporation of New Zealand| year=1991 | isbn=0-908912-16-1}}
• {{cite book | author=Reilly, Helen | title= Connecting the Country: New Zealand's National Grid 1886 - 2007| location=Wellington| publisher=Steele Roberts| year=2008 | isbn=978-1-877448-40-9}}

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• [http://www.teara.govt.nz/en/manawatu-and-horowhenua-places/7 Beneath the Tararua Ranges (page down)]

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Category:Energy infrastructure completed in 1924

Category:Hydroelectric power stations in New Zealand

Category:Buildings and structures in Manawatū-Whanganui