MainPower

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MainPower
Industry Electricity distribution
PredecessorNorth Canterbury Electric Power Board
Founded1928
Headquarters
Rangiora
,
New Zealand
Key people
Tony King (Chair)
Andy Lester (CE)
Parent MainPower Trust
Website www.mainpower.co.nz

MainPower New Zealand Limited is an electricity distribution company, based in Rangiora, New Zealand, responsible for electricity distribution to nearly 42,000 customers in the Canterbury region north of the Waimakariri River. [1] MainPower was formed in 1993, [2] after the Energy Companies Act 1992 required the North Canterbury Electric Power Board to reform into a commercial power company. More reforms in 1998 required electricity companies nationally to split their lines and retail businesses, with MainPower retaining its lines business and selling its retail business to Contact Energy.

Contents

MainPower has initiated a number of local generation projects, including the Mount Cass Wind Farm (proposed) [3] and Cleardale Hydro Power Station (operating). [4]

Electricity network

MainPower has a total service area of 11,180 square kilometres (4,320 sq mi), covering the Waimakariri, Hurunui and Kaikōura districts. The area includes the towns of Kaiapoi, Rangiora, Oxford, Woodend, Pegasus, Amberley, Waipara, Culverden, Cheviot, Hanmer Springs and Kaikōura. [1]

MainPower takes electricity from Transpower's national grid at five grid exit points (GXPs): Kaiapoi, Southbrook, Ashley, Waipara and Culverden. It operates 4,873 km of circuits [1] at 66,000 and 33,000 volts for subtransmission, and 22,000 and 11,000 volts for distribution. As is standard in New Zealand, electricity is delivered to homes at 230/400 volts (phase-to-neutral/phase-to-phase).

In 2011, MainPower purchased the Kaikōura GXP and Culverden to Kaikōura 66 kV transmission line from Transpower. In 2015, MainPower completed works to up-rate the network west of Rangiora towards Oxford to 66/22 kV (from 33/11 kV). Other projects in progress include upgrading the 33 kV subtransmission line between Cheviot and Kaikōura to 66 kV, and preparing for a new "Rangora East" GXP between Rangiora and Woodend to supply Woodend and Pegasus, offloading Kaiapoi GXP.

MainPower New Zealand Limited network statistics for the year ending 31 March 2024 [5]
ParameterValue
Regulatory asset base$328 million
Line charge revenue$60.5 million
Capital expenditure$37.3 million
Operating expenditure$24.7 million
Customer connections44,918
Energy delivered640 GWh
Peak demand117 MW
Total line length5,234 km
Distribution and low-voltage overhead lines3,668 km
Distribution and low-voltage underground cables1,191 km
Subtransmission lines and cables390 km
Poles56,430
Distribution transformers8,493
Zone substation transformers24
Average interruption duration (SAIDI)937 minutes
Average interruption frequency (SAIFI)2.88

The high SAIDI and SAIFI in the 2023/24 years is primarily attibuted to an extreme windstorm in October 2023. [6]

See also

References

  1. 1 2 3 "About MainPower". MainPower.
  2. ↑ "View All Details". app.companiesoffice.govt.nz. Retrieved 2022-09-16.
  3. ↑ "Mt Cass Wind Farm". Archived from the original on 4 October 2011. Retrieved 11 September 2011.
  4. ↑ "Hydro Generation". www.mainpower.co.nz. Retrieved 2018-03-31.
  5. ↑ "Performance summaries for electricity distributors – Year to 31 March 2024". Commerce Commission. 8 July 2025. Retrieved 9 September 2025.
  6. ↑ "Thousands of homes reconnected but some remain without electricity". www.thepress.co.nz. 16 October 2023. Retrieved 2025-09-09.
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