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This folder provides access to datasets that relate to the operation of the retail electricity market.


The wholesale folder provides access to a wide range of data relating to the operation of the wholesale electricity market. For example, final pricing raw case files, vSPD input GDX files, and CSV files containing final prices, half hourly metered data, bids and offers, and much more.

Ancillary services

This folder provides access to datasets that relate to the operation of markets for ancillary services. Electricity markets require ancillary services to ensure the quality and reliability of the electricity supply is maintained at acceptable levels. Offers to supply frequency keeping services are an example of the data available to be downloaded.

Forward markets

This folder provides access to information and datasets relating to forward markets. For example, the weekly report summarising activity on the ASX New Zealand electricity futures and options exchange and the New Zealand electricity hedge disclosure system. Forward markets can take many forms, and enable parties to manage price or location risks by trading contracts derived from the spot market for electricity.


Environmental factors such as weather can significantly influence outcomes in the electricity market. This folder provides access to environmental datasets. For example, lake levels and inflows into hydro storage reservoirs.

Supplementary information

This folder provides access to supplementary information that supports reports published elsewhere by the Electricity Authority. For example, the analysis undertaken to support a consultation project or an industry study.


vSPD is an independently audited, mathematical replica of the Scheduling, Pricing and Dispatch (SPD) market clearing engine used in the administration and operation of the New Zealand electricity market.


GEM, which stands for Generation Expansion Model, is a GAMS-based, long-term capacity expansion model of the New Zealand electricity sector.


Doasa is a version of the stochastic dual dynamic programming technique applied to the solution of hydro-thermal scheduling problems.


The Hydro Supply Security (HSS) test applies a deterministic methodology to calculate the risk of a storable hydro supply shortage by assuming that storable hydro is treated as the last resort supply of energy. The HSS test is encapsulated in a simplified version of the vSPD model.

Reports > Retail


Concentration ratio trends

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Link to this report:


  1. Retail reports are released after the 10th business day of each month. The next scheduled release is due on 13/05/2017. The reports are built off a live system and the data is subject to change as registry events are processed (e.g. backdated corrections or withdrawn switches).
  2. Concentration ratios (CR) measure the share of the market held within a specified number of the largest companies. In this report the user can select the number of firms between one and four. This metric is derived from parent company share of ICPs for the market segment selected in each regional market where retailers operate and compete. The regional markets are represented by the pricing regions or network reporting regions. The concentration ratio presented for other regions is the connection weighted average of the concentration ratio for the network reporting regions.
  3. Market segment breakdowns are available from September 2013 when ANZSIC codes were introduced into the registry in a field maintained by the trader. No breakdown is available at NSP level.
    Market segments are not mutually exclusive. Residential connections have no ANZSIC code. Small and Medium Enterprise (SME) connections are defined as those assigned meter categories 1 and 2 (low voltage up to 500A) with an ANZSIC code excluding those relating to central or local government and other utility services. Industrial connections have ANZSIC code from A through E and commercial connections F through Z. More information on ANZSIC codes is available at
  4. Region types are either network based or derived from standard statistical boundaries. Network based regions are network supply points (NSP), network reporting regions and zones, mappings are available in the NSP table which is available as a wholesale report. Other regions are derived from ICP location data and statistical boundaries (2013 census). ICPs without location data default to the location of their NSP. Main centres use Territorial Authority boundaries (city councils) where Wellington includes Porirua City, Upper Hutt City, Lower Hutt City, and Wellington City. The data report lets users select 'All regions' (where the regions are not the data series) to get data for all regions in a single file. Regions are listed North to South except for NSPs
  5. For more information on specific terms and their definitions please visit the glossary on this website.