CyrusOne Dublin (DUB1) data center, Dublin, County Dublin

CyrusOne operates its DUB1 data center in Grange Castle Business Park in west Dublin: three buildings with 22,854 square meters of technical space and 14 megawatts of power. It is cooled by closed-loop water systems, backed by two separate power feeds capable of 80 megavolt-amps combined, and CyrusOne says it runs entirely on renewable electricity.

South Dublin County Council granted planning permission for the 400 million euro campus in October 2018: about 349,000 square feet across two buildings on nearly 15 acres, expected to employ close to 70 people once finished. In July 2023 CyrusOne asked the council to extend that permission, which it granted on November 8, 2023.

The extension covers a second building on the site of a house called Erganagh, with 32 standby generators, an on-site substation and 32 sound-insulated chillers. When Data Center Dynamics reported the filing in 2023, it noted that Ireland's grid operator, EirGrid, had said it would grant no new connection requests in the Dublin area until 2028, and had refused two neighboring proposals over grid capacity.

That freeze began in 2021, when regulators had EirGrid halt new data center connections across the Dublin area over the risk of rolling blackouts. It was lifted on December 12, 2025, on new conditions: on-site power backup able to meet full demand, at least 80 percent renewable electricity, and annual reporting on energy and emissions. Data centers now take close to a quarter of Ireland's electricity, up from about 5 percent a decade ago.

South Dublin County Council still decides any new planning applications at Grange Castle, now under the regulator's December 2025 conditions on new grid connections.