Total energy consumption

Methods - how we monitor

• Where and how we collect the data

  Energy consumption is measured by the Energy Efficiency and Conservation Authority (EECA) and provided in the form of the Energy End Use database.

  Monitoring frequency

  This is dependent on EECA.

  Monitoring history

  The first energy survey for the Waikato region was conducted in 2003. EECA published the 2007 Energy End Use Database in 2009.

  Measurement technique

  The Energy End Use database describes New Zealand's energy use in considerable detail, exploring energy use split by 11 fuels, 32 sectors, 20 end uses, 25 technologies, and by all local authority geographical areas.The database is a top-down estimation of more detailed information. It is essentially an allocation of energy use to different sectors, regions, end-uses, technologies, and fuels based on known information about the distribution of sectors, what energy they use, and how they use it. Specific information has been used where possible but in most cases actual data was not available to fill in these gaps. There are about 40,000 records in the database and these can be aggregated to billions of different numbers.
• How this indicator is compiled

  Energy use data were previously compiled and reported for the region and for Hamilton based on the calendar year. Data was compiled by sector and fuel type.

  Gas data
  We estimated LPG use for transport using national LPG use statistics. Data for the Waikato region were based on New Zealand Transport Agency's territorial local authority VKT data.

  We obtained data for industrial gas use from resource consent data and from contacting industries directly. We targeted industrial activities holding consents for discharges to air, although a few other processes were also included. Methods for estimating gas use for domestic heating are outlined above.

  Transportation data
  We estimated transportation fuel use using petrol tax data provided by territorial local authorities. We estimated aviation fuel use based on the proportion of national aviation fuel consumed in the Waikato region. This was based on aviation carbon dioxide emissions data from the National Transport Emission Inventory. We estimated energy use associated with diesel consumption from rail transport using data from the 1998 Ministry of Transport (MOT) Report Impacts of Rail Transport on Local Air Quality, data from the New Zealand Transport emission inventory and fuel use information supplied by Tranzrail.

  Fuel consumption data were converted to energy use units based on the calorific value of the fuel. Energy consumption data includes losses from within the electricity line network and losses associated with the conversion of fuel to energy.

   
• Limitations

  This indicator depends on industry, electricity line companies, fuel suppliers, fuel transporters and local authorities providing energy use data. Data were not provided by some sources, due to commercial sensitivities, and other less accurate methods of estimating fuel use were used. For example, aviation fuel consumption data and Rockgas gas use data were unable to be provided for commercial reasons. The methods used to estimate fuel use from these sources are likely to be less accurate than total fuel consumption data from retailers.

  Petrol tax data were provided for Hamilton, South Waikato, Hauraki, Matamata-Piako, Thames-Coromandel, Waikato and Waipa districts. These areas contain about 75 per cent of the total number of dwellings in the Waikato region. Petrol tax data from these areas were used to estimate fuel use for the rest of the region.

  No fuel tax data were available for Hamilton alone. Hamilton data were based on estimates of fuel use for Hamilton from road network modelling, carried out by Gabites Porter for the 2001 air emissions inventory. This was extrapolated to 2003 based on projected population growth. These methods provide less accurate estimates than if petrol tax data had been obtained specifically for the whole study area and if the Hamilton use data were able to be segregated on the basis of fuel use.

   
• Quality control procedures

  No technical quality assurance documents have been prepared outlining process, data quality assurance or validation techniques.