Data centre electricity use increases by 20% in just 12 months

Professor Paul Deane, senior research fellow at energy and climate research centre MaREI and senior lecturer in clean energy futures at University College Cork (UCC), said Ireland “can’t have its environmental cake and eat it” when trying to cut greenhouse gas emissions at a time of surging data centre energy use.

“The numbers are incredibly large,” he said. 

“One terawatt hour is a quarter of a million homes worth of electricity on the grid.

“Growing electricity demand is just in direct conflict with our aims to reduce emissions.” 

According to CSO figures, data centres consumed 6.3 terrawatt hours of electricity last year.

Since 2015, the metered electricity consumption of data centres has risen by 400% according to the figures. Back then, data centres accounted for just 5% of electricity use in Ireland. Now, that figure stands at 21%, higher than urban homes (18%) and rural homes (10%).

Separately, other new data from the CSO revealed that large energy users — including the largest data centres and other high-electricity customers in the likes of IT and cement manufacturing — used more electricity than urban and rural homes put together in 2023.

In a revised draft of the Government’s National Energy and Climate Plan sent to the European Commission this month, it acknowledges data centres can require “the same amount of energy as a large town”.

“Eirgrid’s analysis shows that demand from data centres could account for 31% of all demand by 2027 (in a median demand scenario),” it said.

Given these latest CSO figures, Prof Deane said that certainly seems to be the direction of travel in terms of data centre demand on the grid.

“Ireland has been incredibly successful in attracting these data centres,” he said. “It’s accounting for one fifth of all electricity demand in Ireland. At a global level, we’re closer to 1% of demand, so Ireland is an outlier.

The Government’s plan also noted data centres “pose particular challenges to the future planning and operation of a sustainable power system”. It said this increased electricity requirement will be “mainly delivered by the development of the new Renewable Energy Support Scheme”.

Prof Deane said it was not just about technology, but also a question of timing.

“If we already had lots of wind and lots of solar, it wouldn’t be a problem,” he said. “We’re still so reliant on fossil fuels. We need to be able to build up renewables very quickly. We’re good at building large data centres quickly but not as good at building renewables.” 

The UCC expert said it was a vital race for Ireland to win if it is to meet its commitments, even though there are projects planned down the tracks.

“The problem is the present,” he said. “We need to build all these renewables first, and emissions aren’t going down quick enough. We have been too slow at building a lot of this stuff, and demand is still outstripping supply.

“It’s a difficult one to square. We will not be able to continue on this path.”