EirGrid
Ireland's state electricity transmission operator; its adequacy warning puts data centre reconnection on a collision course with grid capacity.
On 30 June, EirGrid and SONI set a 900 MW ceiling on sudden data-centre demand loss, bringing a grid-code limit into force in July as Irish supply forecasts pointed to peak shortfalls through 2028.
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EirGrid warns supply will fall short through 2028; why is the CRU reconnecting data centres?
Timeline for EirGrid
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Data Centres: Boom and Backlash: Ireland codes a 900 MW load-loss limitBackground
EirGrid plans and operates Ireland's high-voltage electricity transmission network. Its REMIT also covers all-island system planning with Northern Ireland's SONI, placing the operator at the point where new large loads meet physical grid limits.
Ireland's data-centre debate gives that technical role public weight. On 30 June, EirGrid and SONI applied a procedure for sudden data-centre demand loss, while the CRU considered connection obligations for sites on the transmission network on 29 July.
EirGrid does not grant planning consent or set national industrial policy. Its durable function is to model capacity, plan transmission and define the operational conditions needed to maintain a secure electricity system as demand changes.
EirGrid limits demand loss
On 30 June, EirGrid and SONI issued a procedure limiting instantaneous data-centre demand loss to 900 MW. The procedure took effect in July and warned that loss above 1,150 MW could create a grid imbalance.
For EirGrid, the measure turns an adequacy concern into an operating constraint. The CRU closed consultation on modification 345 on 29 July, covering fault ride-through, rate-of-change-of-frequency and active-power-recovery duties for transmission-connected data centres. Those obligations determine whether EirGrid can keep the wider network stable when large loads disconnect.
EirGrid faces load outside its queue
On 1 April, a 110 MW Pure DC microgrid entered service in Dublin outside Ireland's grid connection queue. The CRU had required EirGrid and the distribution operator to publish a data-centre connection process by 31 March, but no process appeared in the following 26 days.
For EirGrid, behind-the-meter generation complicates demand planning. A March-commissioned 110 MW Dublin microgrid later became a model for a route under which operators could seek approval with on-site generation while the EirGrid queue cleared. The operating challenge is to assess system adequacy while major prospective loads use alternatives to a normal transmission connection.