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Hydro stations

Our seven hydro power stations generate enough renewable electricity to power around 1.4 million homes.

On this page:

How hydroelectricity works Water stewardship Habitat enhancement and restoration Hydro Asset Management Plan Power Up community fund

Where are Meridian’s hydro stations?

Our hydro stations can be found in some of the most scenic places in New Zealand, making them popular spots to visit. We own and operate six power stations in the Waitaki hydro scheme, as well as the country’s largest hydro station – Manapōuri.

Waitaki hydro scheme

The Waitaki hydro scheme is a series of interconnected lakes and canals. It accounts for 16% of New Zealand’s electricity supply and more than 56% of the average hydro-electricity storage. This storage will become increasingly important for ensuring there’s enough power when it’s required as more wind and solar are introduced into the electricity system, as these rely on wind or sun being available to generate electricity.

The Waitaki hydro scheme consists of eight power stations. Meridian owns and operates six of them: Aviemore, Benmore, Waitaki and Ōhau A, B and C. The other two (Tekapo A and B) are owned and operated by Genesis Energy.


Waitaki Hydro Scheme

 

  • Aviemore Header v2

    Aviemore

    The Aviemore generators are dimensionally the largest in New Zealand. The rotors are nearly eight meters in diameter and weigh 210 tonnes.

    Aviemore
  • Benmore Header

    Benmore

    Benmore is the country’s second-largest hydro station after Manapōuri. It generates enough electricity for about 298,000 average New Zealand homes.

    Benmore
  • Ohau A Header

    Ōhau A

    Ōhau A generates enough electricity for about 144,000 average New Zealand homes.

    Ōhau A
  • Ohau B Header

    Ōhau B

    Ōhau B has four 53-megawatt generating units and a generation output of up to 212 megawatts.

    Ōhau B
  • Ohau C Header

    Ōhau C

    Ōhau C is a twin station with Ōhau B. Its commissioning in 1985 completed the Waitaki power scheme.

    Ōhau C
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    Waitaki

    An art deco gem, Waitaki generates enough electricity for about 51,000 average New Zealand homes.

    Waitaki

The largest hydro power station in New Zealand

Manapōuri

Manapōuri is the largest hydro power station in New Zealand. It’s located on the edge of Lake Manapōuri’s West Arm in Fiordland National Park, which has UNESCO World Heritage status as part of Te Wāhipounamu.

Manapōuri
Manapouri inflow

How does hydroelectricity work?

A dam holds water in a big lake. When we need electricity, we let the water flow down through a special pipe (a penstock) to a turbine. These look like large wheels with wide spokes. The force of the water makes the turbine spin, and its rotation drives a generator that turns that spinning motion into electricity.

Most of Meridian’s electricity is made from the energy of falling water. Our hydro stations generate enough electricity to power around 1.4 million homes.

It’s not possible to store large amounts of electricity, but it is possible to store water in dams.

Keeping an eye on the water

 

  • Lake view

    Current lake levels

    Here you can access information on the dimensions of each of the lakes we use to generate energy (Aviemore, Benmore, Manapōuri, Ōhau, Pūkaki, Te Anau and Waitaki), as well as recent lake-level, snow storage and river-flow data.

    Lake levels
  • Lake and snowy mountains

    Current snow storage

    We manage about 50% of New Zealand’s total hydro storage. We collect information on lake levels as well as the amount of water stored as snow, so we can estimate their impact on inflows.

    Snow storage
  • People working in the water

    Water stewardship

    We work closely with iwi and a range of stakeholders to balance the different economic, social, cultural and environmental implications of water use in New Zealand.

    Find out more

Resource consent compliance

Our hydro power schemes operate under strict resource consent conditions. You can read the independent compliance reports below.

Waitaki Hydrometric Compliance Report 

Manapōuri Hydrometric Compliance Report

 

Dry river bed safety

At times Meridian must release water from our stations as part of our resource consent agreements. We update the signage nearby to let people know when we’re going to do this and also publish announcements on our Facebook page.

If you’re camping or fishing in a dry river bed, you must follow all instructions. If you see water appear, the most important thing to do is get out of the water and stay out.

If you want more information on planned flow releases, head to the Environment Canterbury river flow data website.

Habitat enhancement and restoration

We’re privileged to be a kaitiaki of the local waters we use to generate electricity. It’s important to us that we take care of them, as well as the species that live in them.

We’re constantly monitoring the impacts of our hydro stations and water management, and working with iwi and the wider communities on initiatives to lessen these impacts. Generally, the impacts relate to the effects on water-based species of inundation, dry river beds and habitat loss.

  • River in the hills

    Project River Recovery

    We have a long-term partnership with the Department of Conservation, which runs Project River Recovery, helping preserve flora and fauna in the Upper Waitaki Basin’s braided rover habitats. Meridian has been involved in and has funded this programme since 1991.

    Project River Recovery
  • River flow

    Waiau River restoration

    The Waiau River restoration work is a partnership between Meridian and the Waiau Fisheries and Wildlife Habitat Enhancement Trust. The Trust manages a number of habitat-enhancement projects that improve the ecological health of the Waiau River.

    Waiau River restoration
  • People doing conservation work

    Elver trap and transfer

    The Waiau and Waitaki catchments are the natural habitats of thousands of native tuna (eels), but the building and operating of dams in these areas have affected their migratory habits. Meridian and Ngāi Tahu operate an annual programme to move thousands of tuna by trapping and transferring the elver (young tuna) upstream from our dams and moving the tuna heke (migrant adult eels) back downstream to spawn.

    Elver trap and transfer

Hydro Asset Management Plan

From time to time we need to remove generation assets from service to enable their proper management, maintenance and upgrades in accordance with prudent asset-management practice.

In accordance with the Electricity Industry Participation Code 2010, we disclose all generation asset outages via the Planned Outage Coordination Process (POCP) platform as soon as we have sufficient information about outages, their likely timing, and duration. There are also future works in Meridian’s Hydro Asset Management Plan with an outage impact which, as at the date of the table below, we do not yet have sufficient information to include in POCP. These outages are listed below.
 
Please note this list does not necessarily include all of Meridian’s regular maintenance outages. We will disclose them on POCP as the outages in the table become more definite, meaning after the date indicated on the table, the table may include outage information that is also listed on POCP. Please note, this is only a plan and is subject to change depending on a wide variety of circumstances. The table is correct as at the date indicated and we will aim to update it regularly.  

Meridian’s regular maintenance outages schedule 

As at 05 September 2024
 Year
 Station
 MW Impact
 Duration
 Notes
FY2026 OHA 66 16 Rotor rim re-shrink & Bypass Valve works
  OHC 53 12 Rotor off alignement correction
  OHB 53 6 Combined bearing cooling water pipework replacement
  OHC 53 3 Combined bearing cooling water pipework replacement
  BEN 95 20 Headgate controls upgrade, bushings replacements and U6 gate refurbishment
  WWD 44 6 Install new T2 transformer
  BEN 95 21 Penstock seismic strengthening
  MAN 128 52 Replace facing plates & wicket gates, automation upgrade and install new step up transformer
FY2027 BEN 95 30 Penstock seismic strengthening
  MAN 128 42 Replace facing plates, automation upgrade and install new step up transformer
  OHB 53 11 Excitation & protection upgrade
  OHC 53 11 Excitation & protection upgrade
  OHA 66 6 220kV CB replacements
  WTK 15 26 Headgate works
  WTK 30 26 Headgate works
FY2028 MAN 128 42 Replace facing plates, automation upgrade and install new step up transformer
FY2029 MAN 850 3 days Station outage

 

Empowering communities in our backyard

Our Power Up community fund supports local projects in the areas where we operate. It’s one of the ways in which we recognise the importance of local communities to our operations.

If you’re near a Meridian power station and have a project you’d like help with, apply now!

Power Up community fund

Our other generation assets

Hydro energy generation is only part of what we do. Find out more about our solar progects, wind farms and future projects.

Wind farms Solar New projects

Tackling Zero

Tackling Zero is Meridian’s quarterly newsletter for people whose roles or studies are focused on sustainability, or for whom this is an area of interest. Each issue will offer Meridian’s insights into a topical sustainability issue, as well as stories on how we, our customers and supply chain partners are tackling sustainability. It also includes links to recent Meridian disclosures such as new policies and reports.

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