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Ireland refuses €1.5bn Mayo data centre

1 min read

10:53UTC

Ireland's planning appeals body refused a €1.5bn data centre at Killala, County Mayo, because the developer showed no fixed grid connection and no renewable power contract.

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Key takeaway

Ireland's planning appeals body refused a data centre that could not prove grid capacity or renewable supply.

An Coimisiun Pleanala, Ireland's national planning appeals body, refused a €1.5bn data centre at Killala, County Mayo, on 17 September, overturning Mayo County Council's 2025 grant⁠¹. The applicant, Mayo Data Hub, is backed by Avaio Digital.

The board found the developer had shown no fixed grid connection agreement and no proof that the grid could serve the site, RTE News reported. It also found the project had not shown it would meet the objectives of Ireland's Climate Action Plan 2025, citing the absence of any corporate PPA (power purchase agreement) with a renewable supplier.

Ireland's energy regulator, the Commission for Regulation of Utilities, had been consulting on grid-code obligations that EirGrid would impose on large demand sites such as data centres. Killala moves those tests forward to the planning stage. An Irish applicant now faces a demand for grid and power-purchase evidence at the planning stage, before any connection offer.

Deep Analysis

In plain English

Ireland's national planning appeals board rejected a €1.5bn data centre planned for Killala in County Mayo, even though the local county council had already approved it last year. The board's reasons were about power, not politics: the developer had no confirmed grid connection agreement, and no signed contract to buy renewable electricity. This matters beyond Mayo because it shows Ireland's appeals process is now applying the same tough grid and renewable-energy tests used around Dublin to projects anywhere in the country, even regions once seen as an escape route from Dublin's stricter rules.

Deep Analysis

Root Causes

Ireland's grid has operated under an effective restriction on new large-load connections around Dublin since 2021, pushing developers toward the regions; Mayo Data Hub tried to build outside that constrained zone but still needed the grid operator to confirm the west of Ireland's thinner transmission network could serve a €1.5bn campus, and went to appeal without that confirmation in hand.

The refusal also rests on the absence of a corporate power-purchase agreement, a financing instrument rather than a planning requirement in most jurisdictions; treating a missing PPA as grounds for refusal signals Ireland now expects developers to prove renewable electricity is contracted, not merely available, before construction can begin.

Source Landscape

This story draws on neutral-leaning sources from Belgium

Belgium

Consensus view: An Coimisiun Pleanala's ruling tracks Ireland's grid operator, which has restricted new large-load connections around Dublin since 2021 and told developers elsewhere that a planning grant without a firm connection offer is not bankable; Mayo Data Hub's lack of a signed agreement was the fact the appeals board treated as decisive.

Counter-view: Mayo County Council's 2025 grant, which this ruling overturns, judged the project on land use and local economic benefit, the criteria it is statutorily required to weigh; the counter-case is that national grid policy should not retrospectively unwind a decision a county council had no power to make itself.

Key tension: Whether Ireland's national appeals board will keep applying a grid-and-contract test county councils cannot themselves enforce, effectively centralising data-centre planning decisions regardless of where a project sits.

Sources:European Commission

Mentions:Dublin →EirGrid →Ireland →An Coimisiun Pleanala →Killala →Mayo Data Hub →Avaio Digital →Climate Action Plan 2025 →Mayo County Council →RTE →

First Reported In

Update #15 · Texas freezes data-centre permits

European Commission· 24 Sept 2026

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Causes and effects

Caused by

Ireland writes the grid rules into contracts

Grid-code obligations regulators were writing into connection rules became grounds cited in the Killala refusal.

Occurred 29 Jul 2026

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This Event

Ireland refuses €1.5bn Mayo data centre

In An Coimisiun Pleanala's decision, missing grid-capacity evidence and a missing renewable PPA became grounds to refuse planning permission, ahead of any grid connection.

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