The energy regulator is proposing restrictions on data centres after warnings of a further surge in demand for electricity.
Eirgrid says it has so many new applications from data centres looking for electricity connections, that to supply them would be the equivalent of 70pc of national power use.
The grid operator wrote to the Commission for the Regulation of Utilities (CRU) in recent days, warning that data centres would represent 33pc of all electricity consumption by 2030, based only on existing connection agreements.
Eirgrid said it currently had agreements to supply 1800 megawatts (MW) of power to data centres but it had received a spate of applications seeking 2000MW more.
The total demand of 3,800MW would equate to 70pc of the peak demand for electricity by the whole country which is around 5,500MW on a high-usage day in winter.
In the letter to the CRU, Eirgrid’s Group Head of Regulation, Bill Thompson, said: “We are facing a more acute security of supply situation than we have had in the recent past.
“The rate at which data centres are seeking to grow their load is unprecedented.”
He said growth in demand by data centres over the past four years was the equivalent of adding 140,000 households to the power system each year.
He said growth was escalating again and the 33pc forecast would be outstripped.
“This is a current forecast position. It does not include all of the most recently received data centre applications seeking connection,” he said.
They totalled 2,000MW, he said. “To put this in context, Ireland has a current demand peak of around 5,500 MW.
Mr Thompson said many of the data centres had or were seeking “extremely large loads” that were the equivalent of a large town or a small city such as Kilkenny.
He said a national debate was needed on what he called the “data centre phenomenon”.
“Ireland’s electricity system was surely not planned to be, nor designed to be, a system which seeks to serve the needs of the global citizen for increased data supported by an ever proportionately smaller non-data centre commercial, industrial and domestic load,” he said.
“It surely must...give rise to consideration and potentially wider national debate as to that which is in the public interest in this regard.”
Concern is growing about electricity shortages before there are enough wind and solar farms to replace the phasing out of fossil fuel generating stations.
In response, the CRU is proposing directing EirGrid and ESB Networks to prioritise application requests by data centres that are located in areas where power supply is less strained, that can provide their own power or power storage, and that can reduce demand on the general network when instructed to at times of constraint.
The proposal is being put to public consultation until July 7 but the CRU said: “Security of supply is increasingly at risk, in significant part due to the considerable increase in data centre demand.
“Accordingly, the CRU is of the view that intervention is necessary and appropriate.”