Two and a half years after it was granted, the planning permission for the data centre campus outside Ennis, County Clare, has run out of courts in which it can be challenged. On Monday 12 October Ireland's Supreme Court dismissed an application by five opponents for leave to appeal the High Court judgment that had upheld the permission, the Irish Times and RTÉ reported the same day. Art Data Centres, the developer, says construction will start in 2027 once the remaining arrangements are in place.
Three Grounds, No Point of Public Importance
The application was brought by Colin Doyle, Friends of the Irish Environment, Futureproof Clare, Martin Knox and Christine Sharp. Their case was that building the data centre without offsetting its greenhouse gas emissions raised a point of general public importance in the light of Ireland's climate targets. An Coimisiún Pleanála, which granted the permission in April 2024, answered that a project causing emissions is not in itself an exceptional circumstance and that the argument ignored the steps the commission had taken to mitigate them. The Supreme Court dismissed all three grounds: the application did not meet the constitutional threshold for a further appeal, and no point of general public importance arose. The High Court had already dismissed the judicial review in March and later refused permission to appeal.
Tom McNamara and Vincent Fogarty, the company's founders, called the ruling good news for Clare and said it recognised a future for data centre developments designed with the environment in mind. They describe it as a pillar of the Ennis 2040 economic plan.
What Was Approved in 2024
The permission covers a 200 MW campus of six data halls on 145 acres beside the Tulla Road, on the eastern edge of Ennis near junction 13 of the M18, with the investment put at 1.6 billion euro. Data Centre Review, reporting the ruling on 13 October, lists what goes with the halls: a 110 kV substation, a 120 MW gas-fired generation facility, 66 emergency diesel generators, an energy centre and space for vertical farming and heat reuse. The developer expects up to 1,200 jobs during construction and up to 1,000 once the campus runs. Earlier statements had the first phase, a substation and two data halls, commissioned by the end of 2028; that date may move.
The grid connection is the open item. The company says its connection applications can now be processed, and Data Centre Review notes that the application predates the rules the Commission for Regulation of Utilities introduced in December 2025, under which new data centre applicants must bring generation or storage capacity matching their demand and cover at least 80 per cent of annual consumption from renewable supply. Applications already in the system proceed under the earlier framework. The same regulator is considering whether new gas connections for large industrial users should be interruptible when the gas network is under pressure, which touches the 120 MW gas plant directly.
Two Kinds of Generation on One Fence Line
What makes Ennis worth reading for anyone in the generator trade is the pairing: a gas-fired plant of 120 MW and 66 diesel sets for emergencies on the same site, behind the same substation. The sources do not say how the two are meant to share the work - whether the gas plant runs while the grid connection is awaited, backs up the grid or fills a shortfall - and that division of duty is the first thing a packager asks, because it decides the rating the sets are specified at, the run hours in the air permit and how the fuel store is sized. The Bell Bay case in Tasmania, where the regulator is arguing before a tribunal about exactly that line, shows what happens when it is left vague.
Sixty-six emergency sets are also a yard in their own right: exhaust and cable routes for each containerised unit, a test schedule the neighbours along the Tulla Road will hear, and a fuel stock that has to stay usable for years between real outages. With the courts finished, those are the practical questions at Ennis.
Sources: The Irish Times, RTÉ News, Data Centre Review