Onekaka Power Station is a small 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 10 m (33 ft) high, a penstock 1.25 km (0.78 mi) long, and a powerhouse containing a Boving pelton wheel, rated at 250 kW.[1]
| Onekaka Hydro Power Station | |
|---|---|
 The power station in 2024 | |
| Country | New Zealand |
| Location | Onekaka |
| Coordinates | 40°46′56″S 172°41′15″E / 40.78222°S 172.68750°E |
| Dam and spillways | |
| Type of dam | Concrete arch |
| Height | 10 m (33 ft) |
| Power Station | |
| Operator(s) | Onekaka Energy Ltd |
| Commission date | November 2003 |
| Hydraulic head | 200 m (660 ft) |
| Turbines | Two |
| Installed capacity | 940 kW |
| Annual generation | 3.8 GWh |
After the Onekaka Ironworks closed, the power station remained in operation from 1937 to 1944, generating electricity for the Golden Bay area.[2] The scheme was abandoned in the 1950s. A group of local hydro enthusiasts began work on a rebuild in 1995,[3] and formed a company Onekaka Energy Ltd to manage the re-development and operation of the scheme.[4] Up to 500 litres (110 imp gal; 130 US gal) a second would be diverted from the Onekaka River,[5] and opponents expressed concerns that a reduction in minimum flows in the river would affect the native fish, the shortjaw kōkopu.[6]
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 180 m (200 yd), to a new powerhouse downstream from the original site. New generating equipment for the scheme was obtained from salvage of two 500 kW auxiliary hydro-generator sets that had originally been used at the Tuai Power Station, a 60 MW station built as part of the Lake Waikaremoana scheme in the 1920s. The hydraulic head of the station is 200 m (660 ft)[7] and the rated capacity of the new generating plant is 940 kW.[3] It was commissioned in November 2003,[8] and produces 3.5 GWh annually. The output is sold on the New Zealand electricity market.[3] The scheme produces 10 to 20 percent of the electricity used in Golden Bay.[9]
One unusual feature of this power station is that it is remotely monitored and controlled using text messages via the cellular phone network.[3]
References edit
- ^ "Onekaka Hydro-electric Power Scheme". New Zealand Heritage List/Rārangi Kōrero. Heritage New Zealand. Retrieved 11 February 2024.
- ^ "Onekakā Ironworks". Engineering New Zealand Te Ao Rangahau. Retrieved 11 February 2024.
- ^ a b c d Leyland, Bryan W. (1 September 2009). "SMALL HYDRO: Practical Development: The Story of 940-kW Onekaka". Renewable Energy World. Retrieved 11 February 2024.
- ^ Sparrow, Brandon (11 October 2002). "New power scheme for bay welcomed". The Nelson Mail. ProQuest 274484431.
- ^ "Hydro consents hearing". The Nelson Mail. 27 July 2005. ProQuest 274452145.
- ^ Hindmarsh, Gerard (10 September 2022). "A 100-year contribution to education and culture". The Nelson Mail. ProQuest 2711986268.
- ^ "Powerhouse switches on to feed the national grid". The Press. 3 November 2003. ProQuest 314565312.
- ^ "Bay hydro powers up". Nelson Mail. 3 November 2003. ProQuest 274522037.
- ^ Gale, Haley (3 December 2010). "Council refunds fees for hydro scheme". The Nelson Mail.