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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 savings

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  1. The average residential savings figures are estimates of the savings available in each calendar year if all residential consumers had switched from their electricity supplier to the ‘cheapest supplier’ in their region in each month. The figure is a measure of the average dollar amount that residential consumers would have paid over and above the cheapest retailer's standard offering in their region during that year. This does not represent the average amount saved by switching. The analysis does not take into account how retailers and the market might respond in the future.
  2. The analysis takes into account: all residential consumers (active residential ICPs from the registry), the monthly consumption at residential ICPs (from retailers) assuming 40% is for hot water where plans have separate tariffs, each consumer's electricity supplier - including any changes (from retailers and the registry), standard pricing plans for each retailer in each region and any price changes (from the Consumer Powerswitch tariff database).
  3. It is important to compare equivalent plan types within pricing regions. The following assumptions are used.
    • Standard plans are defined as composite or economy plans where hot water can be controlled. In the absence this tariff type being available for the retailer and/or region, a tariff option with an anytime/controlled combination is selected where the controlled portion is generally not more than 5 hours. However, there are many other plans available. The connection capacity selected for standard plans is 15kVA (or 20kVA where this is not available). Where tariffs differ in a region by connection density (due to the distribution tariff component), we have selected the higher density or urban tariff. This will be the lower cost tariff.
    • Tariffs available at the start of the month applied for the month.
    • No fixed term contracts are taken into account.
    • No secondary benefits including incentive or retention payments are taken into account. Secondary benefits not taken into account also include any rebates like the Tauranga Energy Consumers Trust (TECT) rebate to Trustpower consumers in Tauranga.
    • All consumers pay on time and receive any prompt payment discount available from their retailer. This included the Trustpower friends loyalty discount when it was available.
    • After 2014 75% of consumers receive an electronic discount (for example Contact and Mercury plans) if available. In 2012 and 2013, 25% and 51%, respectively, of Contact's consumers received the electronic discount.
    • A consumption weighted average annual tariff is applied to Powershop plans and plans with a winter/summer rate.
    • A discount of 4.17% (1hour/24hours) was applied to Electric Kiwi consumers' bills to account for one free hour of electricity per day without any behaviour change in 2016.
    • Spot priced plans are excluded from the set of available plans to switch consumers to within the savings analysis as these plans are not comparable with other fixed price variable volume offers and may not be suitable for all consumers. Connections served by a trader offering spot priced plans are counted as zero savings available - meaning these connections act to reduce the average savings in a region and do not contribute to the total savings available. This approach applies to both Flick Electric (starting 2015) and Paua To The People (starting 2016).
    • Some small retailers are excluded from this analysis as we have insufficient information. However, due to the small number of connections these are not considered material.
  4. Each year these assumptions are reviewed and adapted to adjust to changes retailers make to their supply offers. In addition as new or improved information becomes available this is incorporated into the analysis.