Electricity consumption by data centres increased by almost one third in just one year, according to new figures from the Central Statistics Office.
The latest statistics show that data centres used up a greater share of electricity consumption than rural homes in the State last year.
The overall share of metered electricity consumed by data centres has almost tripled in just six years, from 5 per cent in 2015 to 14 per cent last year.
By comparison, urban homes accounted for 21 per cent of metered electricity consumed in 2021 compared with 12 per cent consumed by rural dwellings.
The figure for electricity consumption by data centres last year represents an increase of 32 per cent in that year.
Data centres consumed 265 per cent more electricity in the three-month period between October and December 2021 compared with the three months between January and March 2015.
Total metered electricity consumption increased by 16 per cent over the six years with data centres accounting for the 70 per cent of the increased consumption over that period.
"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," said Niamh Shanahan, statistician in the CSO's environment and climate division.
The surge in electricity use by data centres has come under scrutiny due to concerns about the State’s energy supply and the targeted reduction in carbon emissions to tackle climate change.
Last November the State’s energy regulator, the Commission for Regulation of Utilities, decided against a moratorium on new data centres connecting to the national grid but reserved the right to impose one in the future if deemed necessary to “protect security of supply”.
The regulator said there was an “evolving, significant risk” to electricity security of supply in the State and that a “significant contributory factor” to this risk was the growth of data centres.
Eirgrid, the State's electricity grid operator, has said that electricity usage by data centres could rise to between 23 per cent and 30 per cent of overall consumption by the end of this decade.
The operator has said that it will not connect new data centres in Dublin for the foreseeable future because energy supply in the greater Dublin area is constrained.
The latest CSO data, the second set of statistics released on data centre electricity consumption, shows that quarterly consumption by the centres has dramatically increased over the past six years.
Metered electricity consumption by data centres increased from 290 gigawatt hours in the period from January to March 2015 to 1,058 in October to December 2021.
A gigawatt of power is enough electricity to supply more than 500,000 homes.
Large energy users who consume high amounts of electricity accounted for 23 per cent total metered consumption in 2021. Overall, electricity consumption increased by 5 per cent last year.
The CSO began compiling and publishing data on electricity consumption in January.
Data centres use up a considerably higher share of electricity in the State than in other countries. A 2020 European Commission put average data centre usage in 2018 at 2.7 per cent of electricity demand, compared with 14 per cent in Ireland.
Dr Patrick Bresnihan, a geography lecturer at Maynooth University, said further increases in electricity use by data centres should lead to a debate about whether the Government should block the opening of more centres in order to reduce emissions in light of the recent warnings about climate change.
“There should be more discussion and more serious consideration of a moratorium,” he said.
“I know Eirgrid have announced a de facto moratorium on data centres in the Dublin region but the emphasis there is on the security of supply; it is not about overall emissions and the energy consumption of data centres.”
Allowing electricity consumption by data centres to continue to increase would make it harder for the Government to push policies where it is asking individuals to reduce consumption at a time “when consumption by data centres is so high and clearly just growing,” said Dr Bresnihan.
The latest CSO data gives “statistical credence to people’s informal sense that there is some kind of unfairness or some injustice here,” he said.
People would see a “mismatch” in calls for “climate justice” where they are asked to change their consumption while electricity consumption by data centres was allowed to increase.
“People aren’t going to swallow it, so it’s not good for climate action,” he said.
A spokesman for the Department of Environment, Climate & Communications said the Government was carrying out a review of its strategy on data centres to ensure any increase in their number can only happen in line with “sectoral emissions ceilings and renewable energy targets”.
He said the review, announced late last year, was expected to be completed by the end of June.
He also pointed out that the Government’s National Energy Security Framework, published last month, will aim to ensure that the review sets out a policy direction for data centres to reduce their burden on the national electricity grid and provide demand flexibility at peak times.