Electricity use by data centres is now so high it matches that of all rural homes in Ireland, latest figures show.
Central Statistics Office (CSO) records show that data centres proliferated so much from 2015-2020 that their electricity usage rose by 144pc.
They accounted for 11pc of the country’s total electricity consumption in 2020 – just marginally below the 12pc used by all rural dwellings combined.
Demand for electricity grew generally over the five years, but data centres accounted for 72.5pc of the surge.
Measured in gigawatt hours (GWh), data centres used 3,019 GWh compared to 3,220 by rural homes.
The usage figures are all the more striking as Niamh Shanahan, of the CSO’s environment and climate division, said most of the 3,019 GWh was consumed by just a “small number” of the largest data centres.
Ms Shanahan said the growth in data centre power demand was even more pronounced if viewed on a quarterly basis.
In the first three months of 2015, they used 290 gigawatt hours (GWh) of electricity but by the last three months of 2020, that had risen to 849 GWh – an increase of 193pc.
“The increase in consumption was driven by a combination of existing data centres using more electricity and new data centres being added to the grid,” she said.
This is the first time the CSO has published figures on electricity consumption by data centres but the office says it now intends publishing them annually.
Data centres have come under intense scrutiny for the strain they are putting on national electricity supply at a time when supply is stretched, amber alerts warning of potential power outages have been increasing and prices are rising.
The figures show the facilities used 11pc of all metered electricity in 2020 – up from 5pc just five years earlier.
That is half the 22pc used by all urban dwellings in 2020 and almost equal to the 12pc used by all of the country’s rural dwellings.
Data centres were not the only large electricity consumers to increase demand.
The large user category also covers customers such as IT campuses and cement manufacturers, and the category’s total electricity use grew 54pc over the period.
Consumption by other businesses fell slightly while consumption by households grew but the CSO says those trends – which were most pronounced in 2019-2020 – will have been influenced by the Covid pandemic and the resulting business shutdowns and work-from-home practices.
Vacant properties and holiday homes show up in the figures. The CSO identifies them as customers that used less than 1,000 kilowatt hours of electricity as this is well below the median residential consumption of 3,658 kWh.
County comparisons show Kildare households had the highest median electricity use at 4,224 kWh with Meath and Kildare close behind.
Donegal had the lowest at 2,896, followed by Leitrim and Roscommon. That is likely attributed to the greater proportion of new houses and electrification of heating in the commuter counties.
One surprising trend is the increase in consumption by public lighting as all new lighting uses low-energy LED bulbs and the fitting of older stock with LED replacements has been increasing.