Background
The New Zealand Energy Statistics comprise six surveys of the production of energy commodities:
- Electricity Generation
- Geothermal Steam Production by End Use
- Gas Production
- Crude Petroleum Production
- Petrol Production
- Petroleum Deliveries by Fuel Type
plus the indexes relating to energy commodities from the Consumers Price Index and Producers Price Index.
The information contained within this release is intended for use as a short-term indicator of energy statistics. More comprehensive, but less timely, information and data on New Zealand’s energy sector is available through the Ministry of Economic Development's website at: www.med.govt.nz/energy/info/ or www.med.govt.nz/energy/data/.
Definitions
Biomass
Energy generated from any organic matter that is available on a renewable or recurring basis, including dedicated energy crops and trees, agricultural food and feed crop residues, wood and wood wastes, animal wastes and other waste materials.
Renewables
Energy generated from sources that are not depleted by use, or which can be renewed after use, including solar, wind, hydro, biomass, tidal, wave, and ocean current sources. Geothermal energy is considered renewable, although geothermal fields can be depleted if fluids are extracted at a higher rate than they are replenished.
Electricity generation
This survey is a monthly census of electricity generators, and measures the volume in gigawatt hours (GWh) of electricity generated, by fuel source type, as represented by sales to external users. Small private cogeneration plants that supply electricity for on-site users with no sales to external users are not captured in the Electricity Generation Survey. The published series record the volumes of hydro and wind, thermal, and total electricity generation, as well as providing seasonally adjusted and trend series. Figures for hydro generation have included a small quantity of generation by wind. As part of an updated electricity series, reference has now been made to the inclusion of this generation type. See below for details of seasonally adjusted estimates.
Geothermal steam production
Production of geothermal steam data are collected quarterly from enterprises engaged in extracting geothermal steam to supply to external users. The production of geothermal steam harnessed for purposes such as generating electricity for on-site users is not captured in the Geothermal Steam Production by End Use Survey.
Gas production
The Gas Production Survey measures the monthly volume of gas extracted in New Zealand. The survey in its present form began in 1974, and additional oil/gas fields have been added to the survey when they start producing commercially. Data previously available from production censuses are not strictly comparable with data from the present monthly survey. Prior to 1990, data for gas production included gas manufactured at gas works, but this has been discontinued following the cessation of this form of production.
Crude petroleum production
This survey records the volume of crude petroleum condensate and naphtha (excluding natural gas and liquid petroleum gas (LPG)) extracted in New Zealand.
Petroleum production by fuel type
The Petroleum Production Survey measures the monthly volume of petroleum products refined in New Zealand from indigenous crude petroleum, imported crude, and imported semi-refined petroleum:
- Refined petrol
- Premium (95 octane or greater)
- Regular (91 octane)
- Diesel (auto gas oil)
- Other oil products (for example aviation fuel, kerosene, heavy and light fuel oils
Petroleum deliveries by fuel type
The Petroleum Deliveries by Fuel Type Survey collates the volumes of petroleum fuel products which are distributed to resellers and direct to industry by all the oil companies operating in New Zealand. The fuel products delivered include the outputs of the refinery plus imported fully-refined petroleum products.
Energy price indexes
The energy price indexes measure changes in prices paid by commercial or household consumers.
Coverage and calculation
The household price indexes are collected as part of the Consumers Price Index and represent prices that householders pay. Prices are surveyed in 15 urban areas. Monthly prices are collected for electricity, gas, and alternative motor fuels. Coal and firewood prices are collected in the middle part of the quarter. Petrol prices are collected weekly, having been collected twice monthly prior to April 2002.
The commercial price indexes are collected as part of the Commodity Price Survey (Producers Price Index). Prices are collected mainly by postal survey, with respondents supplying the price at the mid-point of the quarter. Electricity, LPG and natural gas prices are collected from local supply companies and include delivery costs. Bulk diesel and petrol prices, including delivery, are collected from oil companies for several locations around New Zealand. Coal prices are collected from mining companies and exclude delivery costs.
Indexes for commercial electricity and natural gas have been redeveloped as part of the redevelopment of the Producers Price Index. These indexes are now based on a 'typical-consumer' approach. Power companies are asked to supply a single price for each of three specified levels of consumption. The three levels represent small, medium and large consumers. The amount of electricity, time of consumption and line capacity are specified.
The indexes are Laspeyres base-weighted price index series. The weightings are determined by the relative importance of commodities and businesses within the industry. Information from various surveys, censuses and other sources has been used to determine the weightings.
Other price indexes
Other energy price indexes and energy industry indexes are published as part of the Producers Price Index, the Farm Expenses Price Index and the Consumers Price Index. Unpublished energy price indexes at a lower level of aggregation are also available, at a small charge to cover dissemination.
Seasonally adjusted estimates
Seasonal adjustment aims to eliminate the impact of regular seasonal events (such as winter) on time series. This makes the data for adjacent quarters more comparable. All seasonally adjusted figures are subject to revision each quarter. This enables the seasonal component to be better estimated and removed from the series. The largest revisions will occur in the quarters prior to the current quarter.
From September 1998, X-12-ARIMA has been used to produce the seasonally adjusted and trend estimates, rather than X-11-ARIMA. X-12-ARIMA is an updated version of X-11-ARIMA, developed at the U.S. Census Bureau. For completeness and for comparative purposes, the back series has been revised using X-12-ARIMA also. This methodology change has resulted in some additional revisions to previously released figures, due to the slightly different treatment of outliers in the newer package. An extra adjustment has been made for the outliers in 1992 due to the power 'crisis'. These changes have been implemented to ensure that the high quality of the seasonal adjustment process is maintained.
More information
Follow the links from the Technical notes of this release on the Statistics New Zealand website for more information on:
Electricity Gas
Geothermal
Petrol
Crude Petroleum
Petroleum Deliveries
Copyright
Information obtained from Statistics NZ may be freely used, reproduced, or quoted unless otherwise specified. In all cases Statistics NZ must be acknowledged as the source.
Liability
While care has been used in processing, analysing and extracting information, Statistics NZ gives no warranty that the information supplied is free from error. Statistics NZ shall not be liable for any loss suffered through the use, directly or indirectly, of any information, product or service.
Timing
Timed statistical releases are delivered using postal and electronic services provided by third parties. Delivery of these releases may be delayed by circumstances outside the control of Statistics NZ. Statistics NZ accepts no responsibility for any such delay.
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New Zealand Energy Quarterly: December 2007 quarter will be published on 18 March 2008 by the Ministry of Economic Development at www.med.govt.nz/energy/nzeq/.