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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.


Residential consumption

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  1. Consumption data is received annually from retailers in the form of monthly EIEP1 files (transferred from retailers to most distributors). These values have not been loss adjusted back to the grid point of connection where energy is reconciled.
  2. Residential connections are defined consistently with other reports on EMI - they have no ANZSIC code in the registry. To be clear, this definition means they will include connections that may not be to primary residences, for example holiday homes.
  3. Consumption information is cleaned where outliers or data that may not reflect residential use is removed. This involves filtering out ICPs that appear not to be residential given their property name or that have a meter category other than category 1. We exclude any ICPs that use less than 1000kWh or more than 30,000kWh annually. In addition we exclude any ICP using more than 5000kWh in a single month and apply some smoothing. This allows us to calculate an average monthly consumption for various regions. These averages are then scaled by the full number of residential connections to provide estimated totals for the residential market segment. We include a quality attribute (coverage) in the data report that details the percentage of residential ICPs these consumption statistics are derived from.
  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.