SONI
The System Operator for Northern Ireland, which co-issued a fault-ride-through demand-curtailment procedure with EirGrid for data-centre customers.
SONI, Northern Ireland's transmission system operator, co-issued a 900 MW data-centre demand-loss ceiling with EirGrid on 30 June 2026, live from July.
Last refreshed: 4 August 2026 · Appears in 1 active topic
Timeline for SONI
Ireland writes the grid rules into contracts
Data Centres: Boom and BacklashCo-issued the fault-ride-through curtailment procedure with EirGrid
Data Centres: Boom and Backlash: Ireland codes a 900 MW load-loss limitBackground
SONI is the transmission System Operator for Northern Ireland. It operates within the all-island Single Electricity Market it shares with the Republic of Ireland's EirGrid, coordinating supply and demand across the border rather than running two separate systems. That shared responsibility means a sudden loss of demand on one side of the island can destabilise the whole market, which is why SONI and EirGrid issue joint technical procedures rather than acting unilaterally.
The scale of hyperscale data-centre demand on the island has made those joint procedures a live concern: a fault that disconnects several large loads simultaneously risks an imbalance the shared grid cannot absorb without emergency measures.
SONI tightens data-centre fault rules
SONI issued a fault-ride-through demand-curtailment procedure jointly with EirGrid on 30 June 2026, live from July, setting a 900 MW ceiling on instantaneous demand loss from data-centre customers and warning of grid imbalance above 1,150 MW without mitigation. The ceiling responds directly to the scale hyperscale data centres now bring to the island's grid: if a fault causes several large loads to disconnect at once rather than ride through it, the resulting imbalance could exceed what the system can absorb without emergency measures.
The procedure sits alongside a wider tightening of the rulebook. Ireland's Commission for Regulation of Utilities closed its consultation on grid code modification 345 on 29 July, setting fault-ride-through, RoCoF and active-power-recovery obligations for data centres and a 24-month group derogation route for sites unable to comply immediately.