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Background Notes

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This release contains metered electricity consumption for data centres for 2015 to 2020. The data were extracted by the CSO from meter data received from the Electricity Supply Board (ESB Networks).

Consumption unit

Consumption figures are expressed in 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.


The data provided to the CSO covered all meters connected to the mains electricity network. Data centres were not readily identifiable in the meter data so the CSO examined around 2.5 million meters to identify Meter Point Reference Numbers (MPRNs) that we considered were primarily being used for data centre activity. In practice, a small number of data centres accounted for most of the metered electricity consumption.

The CSO used three main approaches. The first was a search for names and aliases of known data centres with a consumption above a half gigawatt hour. The second approach was to examine customers located in specific business parks with a consumption above a half gigawatt hour. The third approach was an examination of all meters with an annual consumption above one gigawatt hour. In addition, reports produced by other organisations, the CSO Business Register, and internet searches were used to supplement our work.

Data quality

There is no agreed definition of a data centre. The CSO identified MPRNs with a high consumption that were not associated with high employment nor with other activity such as cement manufacture. The largest data centres have parent enterprises with high employment levels in Ireland. We included MPRNs linked with data centre activity and excluded MPRNs linked with other activities of the enterprise to the extent that it was possible to do this.


Data for all years are subject to revision. Revisions may arise from including more MPRNs related to existing data centres or excluding MPRNs that were incorrectly included.

Legal basis

The CSO received the administrative microdata under Section 30 of the Statistics Act, 1993.

Tariff group

The data received by the CSO were classified by tariff category (DUoS). The DUoS is determined by factors such as the type of use, maximum import capacity (MIC), and the nature of the connecting network. Data centres were found in different DUoS groups hence the need for the CSO to examine all meters to identify them. Consumption by DUoS group is given in a related statistical release covering all electricity meters.

Release frequency

This release will be published annually.

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