Manufacturing Energy Use Survey: Year ended March 2006

Background to the survey

The 2006 Manufacturing Energy Use Survey (MEUS) was carried out by Statistics New Zealand, in collaboration with the Ministry for Economic Development (MED) and the Energy Efficiency and Conservation Authority (EECA). The survey was designed to collect statistics about the use of energy in the manufacturing industry of New Zealand for the year ending 31 March 2006.

Population

The target population for this survey is all enterprises that operate in New Zealand, classified to Australian and New Zealand Standard Industrial Classification Version 1996 (ANZSIC96) Division C (Manufacturing) on Statistics NZ’s Business Frame.

The survey population was selected by taking all enterprises that met the following criteria:

• rolling mean employment (RME) greater than 10
• economically significant (annual GST turnover figure of greater than $30,000)
• classified to ANZSIC96 Division C
• only live businesses are in the survey population.

For this survey the selection unit was the enterprise, and the collection unit was the geographic unit. There were approximately 3,900 enterprises on the Business Frame that met the criteria. All corresponding geographic units within an enterprise were included in the survey population if they met the same selection criteria. The geographic unit was chosen as the collection unit as initial conceptual testing indicated that the data was more readily available at the site than at the ‘head office’ level. There were approximately 5,500 geographic units on the Business Frame that met the criteria.

The manufacturing industry

The manufacturing industry, as defined by the Australia New Zealand Standard Industrial Classification (ANZSIC 1996) Division C, includes the physical or chemical transformation of materials, substances or components into new products (except agriculture and construction).

In accordance with the ANZSIC96 Division C, the manufacturing industry is subdivided into the following industry groups:

Reference period

The survey collected data for the year ending 31 March 2006. When full-year figures were not provided, the yearly quantity was estimated through extrapolation of the partial-year figures provided, taking into account seasonal variation where possible.

Information collected

The information delivered by MEUS will help fill gaps in current energy statistics and provide a benchmark of energy use information for the manufacturing industry. It will also provide data to feed into current modelling systems that provide current energy-use estimations and future demand forecasts (eg MED’s Energy Data File). This new data will enable the update of modelling assumptions, and subsequent improvement in the accuracy of modelled information.

The following information was collected for the manufacturing industry:

• Electricity. This included all electricity purchased from the national grid and energy sources used for input into electricity generation and cogeneration. This did not include electricity generated on manufacturing sites, to avoid double counting.
• Natural gas, coal and wood and wood waste.
• Electricity generated on-site. This included electricity generated within the confines of the manufacturing site but not necessarily owned by the manufacturer. This figure was not included in total energy used, to avoid double counting.
• Petroleum products. This included the energy products derived from the refining process of crude oil. The following petroleum products were included:
  • Petrol – an aggregated figure of 96 and 91 octane petrol
  • Fuel oil – an aggregated figure of the major intermediate products, notably light fuel oil and heavy fuel oil
  • Diesel
  • Liquefied petroleum gas (LPG).

Survey design

The MEUS was a postal survey conducted by Statistics NZ. The survey was a sample survey; one-stage stratified design was used. The stratification variables were ANZSIC96 and RME.

The survey was sent to 1,576 manufacturing sites. The response rate was just over the targeted rate of 80 percent.

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Units

Joules

The unit of measurement used to report the energy statistics produced from MEUS is the joule. The abbreviations and magnitudes of the joule are as follows:

Calorific values

The energy types were converted to a standard unit (joules) for reporting purposes. This enables the direct comparison of the energy contained in different forms. The conversions were carried out by applying a calorific value (enthalpy value) to each energy type and form. See the table below for the calorific values used for each energy type.

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LPG units

During data collection, figures were provided in kilograms and litres although litres were requested. Based on follow up with respondents, a threshold of 25,000 units of LPG use was set and quantities under that amount were treated as kilograms, quantities over it were treated as litres.

Sampling error

Sampling error is a measure of the variability that occurs by chance because a sample, rather than the entire population, is surveyed. Given a certain sample size, the level of sampling error for any given estimate depends on the number of sampled individuals in the category of interest, and the variability of the estimate due to the random nature of the sample selection.

Sampling errors for this survey were calculated using the relative sample error (RSE) measure. RSEs are the sampling error as a percentage of the estimate. The sampling methodology for MEUS was designed with the main objective of producing estimates of total energy use by the manufacturing industry with an RSE of less than or equal to 10 percent, and by industry group (two-digit ANZSIC96) with RSEs of less than or equal to 15 percent. The overall RSE achieved by MEUS was 4 percent. The following table portrays the RSE for each industry group.

Non-sampling error

Non-sampling errors are present in both sample surveys and censuses, and can occur at any stage of the survey process. Non-sampling errors include errors arising from biases in the pattern of response and non-response, inaccuracies in reporting by respondents and errors in the recording and coding of the data. The size of these errors is difficult to quantify. Statistics NZ endeavours to minimise the impact of these errors through the application of international best practice, where applicable and quality management.

Methodology used to derive aggregates

The data was weighted to represent the entire population (ie businesses of ANZSIC Division C, of RME equal or greater than 10). The data was put through a rigorous quality management programme to minimise the effects of non-sampling biases.

Definitions

ANZSIC

Australian and New Zealand Standard Industrial Classification system

Business Frame

A register of all economically significant businesses operating in New Zealand. The population of the MEUS is drawn from the Business Frame.

Enterprise

A business entity operating in New Zealand either as a legally constituted body such as a company, partnership, trust, local or central government trading organisation, or as a self-employed individual (eg a head office).

Geographic unit

A ‘location’ entity at which economic activity is carried out (eg a factory).

Rolling mean employment (RME)

RME is a 12-month moving average of the monthly employee count (EC) figure which replaces the numbers of full-time and part-time employees.

More information

For more information, follow the link from the Technical notes of this release on the Statistics New Zealand website.

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

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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 delays.