{{Short description|Hydro-electric power station in New Zealand}} {{Use New Zealand English|date=February 2024}} {{Use dmy dates|date=February 2024}} {{Infobox dam | name = Onekaka Hydro Power Station | name_official = | image = Onekaka Power Station - hydrogenerator equipment 08.jpg | image_size = 270px | image_caption = One of the hydrogenerator sets in 2024 | image_alt = View inside a power station | location_map = | location_map_size = | location_map_caption = | location_map_alt = | coordinates = {{Coord|40|46|56|S|172|41|15|E|type:landmark_region:NZ-TAS|display=inline,title}} | country = New Zealand | location = [[Onekaka]] | purpose = | status = | construction_began = | opening = | demolished = | cost = | builder = | designed_by = | owner = | operator = | dam_type = Concrete arch | dam_crosses = | dam_height = {{convert|10|m|abbr=on}} | dam_height_foundation = | dam_height_thalweg = | dam_length = | plant_operator = Onekaka Energy Ltd | plant_commission = {{Date|November 2003|DMY}} | plant_hydraulic_head = {{convert|200|m|ft|abbr=on}} | plant_turbines = Two | plant_capacity = {{Val|940|u=kW}} | plant_annual_gen = {{Val|3.8|u=GWh}} }}
'''Onekaka Power Station''' is a small [[Hydroelectricity|hydro-electric]] generating station on the [[Onekaka River]], in [[Golden Bay / Mohua]], New Zealand. The first power station on the river was built in 1928–29 to provide power for the [[Onekaka Ironworks]]. The original scheme included a concrete arch dam {{convert|10|m|ft|abbr=on}} high, a [[penstock]] {{convert|1.25|km|mi|abbr=on}} long, and a powerhouse containing a Boving [[pelton wheel]], rated at 250{{Nbsp}}kW.<ref>{{NZHPT|5120|Onekaka Hydro-electric Power Scheme|11 February 2024}}</ref>
After the Onekaka Ironworks closed, the power station remained in operation from 1937 to 1944, generating electricity for the Golden Bay area.<ref>{{Cite web |title=Onekakā Ironworks |url=https://www.engineeringnz.org/programmes/heritage/heritage-records/onekak%C4%81-ironworks/ |access-date=11 February 2024 |website=[[Engineering New Zealand]]}}</ref> The scheme was abandoned in the 1950s. A group of local hydro enthusiasts began work on a rebuild in 1995,<ref name=":6" /> and formed a company Onekaka Energy Ltd to manage the re-development and operation of the scheme.<ref>{{Cite news |last=Sparrow |first=Brandon |date=11 October 2002 |title=New power scheme for bay welcomed |work=The Nelson Mail |id={{ProQuest|274484431}}}}</ref> Up to {{convert|500|l}} a second would be diverted from the Onekaka River,<ref>{{Cite news |date=27 July 2005 |title=Hydro consents hearing |work=The Nelson Mail |id={{ProQuest|274452145}}}}</ref> and opponents expressed concerns that a reduction in minimum flows in the river would affect the native fish, the [[shortjaw kōkopu]].<ref>{{Cite news |last=Hindmarsh |first=Gerard |date=10 September 2022 |title=A 100-year contribution to education and culture |work=The Nelson Mail |id={{ProQuest|2711986268}}}}</ref>
The new scheme uses the historic concrete arch dam, but a new penstock was built on the same alignment as the original. The new penstock extends a further {{Convert|200|yd|m|abbr=on|order=flip}}, to a new powerhouse downstream from the original site. New generating equipment for the scheme was obtained from salvage of two 500{{Nbsp}}kW auxiliary hydro-generator sets that had originally been used at the [[Tuai]] Power Station, a 60{{Nbsp}}MW station built as part of the [[Lake Waikaremoana]] scheme in the 1920s. The [[hydraulic head]] of the station is {{Convert|200|m|ft|abbr=on}}<ref>{{Cite news |date=3 November 2003 |title=Powerhouse switches on to feed the national grid |work=[[The Press]] |id={{ProQuest|314565312}}}}</ref> and the rated capacity of the new generating plant is 940{{Nbsp}}kW.<ref name=":6">{{Cite web |last=Leyland |first=Bryan W. |date=1 September 2009 |title=SMALL HYDRO: Practical Development: The Story of 940-kW Onekaka |url=https://www.renewableenergyworld.com/storage/small-hydro-practical-development-the-story-of-940-kw-onekaka/ |access-date=11 February 2024 |website=Renewable Energy World |language=en-US}}</ref> It was commissioned in November 2003,<ref>{{Cite news |date=3 November 2003 |title=Bay hydro powers up |work=Nelson Mail |id={{ProQuest|274522037}}}}</ref> and produces 3.5 GWh annually. The output is sold on the [[New Zealand electricity market]].<ref name=":6" /> The scheme produces 10 to 20 percent of the electricity used in Golden Bay.<ref>{{Cite news |last=Gale |first=Haley |date=3 December 2010 |title=Council refunds fees for hydro scheme |work=The Nelson Mail |id={{ProQuest}}}}</ref>
One unusual feature of this power station is that it is remotely monitored and controlled using text messages via the cellular phone network.<ref name=":6" />
<gallery mode="packed" heights="150" caption="Onekaka Power Station"> File:Onekaka Dam under construction.jpg| Onekaka Dam under construction in the late 1920s File:Onekaka Dam 860.jpg| Onekaka Dam in 2024 File:Onekaka Power Station - penstock section.jpg|Penstock section File:Onekaka Power Station - view of hydrogenerator equipment.jpg|View of hydro-generators File:Onekaka Power Station - hydrogenerator equipment 06.jpg|Generator File:Onekaka Power Station 851.jpg|Power station building </gallery>
==References== {{Reflist}}
==External links== {{commons category-inline|Onekaka Power Station}}<br> {{commons category-inline|Onekaka Dam}} * [https://www.sp.co.nz/rural_news/articles/power.html Onekaka Power Station] at Nelson Marlborough Rural News
{{Tasman District|state=collapsed}}
[[Category:2003 establishments in New Zealand]] [[Category:Buildings and structures in the Tasman District]] [[Category:Golden Bay]] [[Category:Hydroelectric power stations in New Zealand]]