Background Notes

Networked Gas Consumption

Introduction

This release contains consumption data from Gas Networks Ireland on all connections to the mains gas network.

Consumption units

The data are gross calorific values expressed in kilowatt hours (kWh) or Gigawatt hours (GWh). A kilowatt hour is a unit of energy equivalent to one kilowatt of power sustained over an hour. A Gigawatt hour is equivalent to one million kWh. Kilowatt hours are used for presenting median figures and gigawatt hours for presenting aggregates.

County

The CSO extracted the county and Dublin postal district from the postal address provided by Gas Networks Ireland. Additional work was required to identify a county for the largest non-residential customers as these were provided in a separate monthly file that did not contain the customer's address. There was a very small number of dwellings connected to the gas network in Wexford in 2016. The figures for Wexford should not be regarded as covering the full year. Accordingly we have excluded Wexford from Figure 3.

Coverage

The data cover all consumers connected to the natural gas network. This includes power plants, non-residential, and residential customers. Five counties (Donegal, Kerry, Leitrim, Longford, and Sligo) had no meter connections. The 2016 Census of Population showed that there were around two million households in Ireland of which 1.7 million were occupied. This release showed that there were around 660,000 residential gas meters in 2016. The release contains a map showing the location of the residential meters using the coordinates provided by Gas Networks Ireland (see Figure 4).

Data quality

The meter readings data were converted to monthly and quarterly consumption estimates by Gas Networks Ireland. Meter readings can be actual or estimated. In some cases an estimated reading that was too high resulted in a low or negative reading for a subsequent period, i.e. no attempt was made to adjust the earlier over or under estimate. The data file provided to the CSO did not provide information on whether the consumption in a period was based on an estimated reading. The results are broadly consistent with Gas Network Ireland reports and with the Sustainable Energy Authority of Ireland energy balances.

Data source

The CSO received the administrative microdata from Gas Networks Ireland under Section 30 of the Statistics Act, 1993. The microdata contain quarterly consumption data for residential and smaller non-residential customers and monthly data for larger users. The CSO received data for 2011-2016 for all customers and for 2006 for residential and smaller non-residential customers.

Median

The median can be regarded as typical usage as it is not influenced by outliers in the same way that the mean or average is. The median for a year is calculated independently of the quarterly medians, e.g. in Table 5A.

Release frequency

This release will be published on an annual basis.

Sector

The data have been classified into three sectors: power plants; non-residential; and residential. Gas Networks Ireland classified the data as residential or non-residential. The CSO classified a small number of customers as power plants. 

There are around 29,000 non-residential customers. The CSO will try to add NACE codes to these records, as NACE would provide a more detailed analysis of the non-domestic customers.

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