Data centres in Ireland: the rules, the numbers and the Naas application under appeal

There is one data centre planning application on the Naas lands on the record we hold: Kildare County Council reference 2460787, lodged by Herbata Limited on 13 August 2024. It seeks six data centre buildings across the townlands of Halverstown, Jigginstown and Newhall, next to the M7 at Naas. Every building has a 24,756 m² data hall, and every building has an external plant area with gas turbines, a gas engine and battery storage. The application also includes district heating infrastructure, rooftop solar, and a Gas Networks Ireland compound with a biomethane injection point.

The council did not wave it through. On 4 October 2024 it asked for further information, and the Irish Times reported four days later that the council had told the applicant the projected emissions would equal 49.35% of the commercial buildings emissions ceiling to 2030, which it called excessive for one development, that the project ran counter to national policy and to the role of data centres in the Government's 2022 Enterprise Strategy, and that on-site gas turbines would not serve the decarbonisation of the energy system. The applicant answered on 26 June 2025. On 20 August 2025 the council decided to grant permission, reported as subject to 77 conditions, many of them governing energy use.

Reported investment figures differ: the Irish Times gave €1bn in October 2024 and €3bn in August 2025. Neither is a figure on the planning register, which does not carry project cost.

The grant was appealed on 16 September 2025 by three parties: the applicant itself, against the conditions, and two third parties, An Taisce and Friends of the Irish Environment with others. ClientEarth, the environmental law charity, later filed an observation with the Commission. The environmental appellants argue that the project is not supported by the Government's Climate Action Plans, and that mitigation such as corporate power purchase agreements and hydrogen is not part of national policy. Those are their arguments, not findings. The Commission has not ruled.

The Commission's own case page still shows a due date of 28 January 2026 and no decision, inspector's report or oral hearing entry. We could not see a revised date. The Irish Times reported on 29 September 2026 that the Commission is expected to rule by January. As a general rule under Irish planning law, a council grant cannot be acted on while an appeal against it is undecided, which matters when reading any map or post that labels the site 'permitted'.

ClientEarth's submission puts numbers on the scheme that are theirs, not the applicant's or the register's: continuous demand of about 240 MW, about 2.1 TWh a year, and about 950,000 tonnes of CO₂ equivalent a year, which it calculates as around 24% of the electricity sector's 2026 to 2030 carbon budget over five years. Treat them as one party's calculation. The Environmental Impact Assessment Report in the file is where the applicant's own figures sit.

Two questions are being merged in the public argument. The first is whether land is zoned for data centres. The Naas Local Area Plan 2021 to 2027 zones lands at Jigginstown and Maudlins for data centre use only, and on 29 September 2026 Kildare councillors rejected two motions to reverse that, by 22 votes to 11 with 7 abstentions. The second is whether a specific scheme has permission. Zoning makes a use acceptable in principle; it does not grant anything. A scheme is still tested against the development plan, the environmental assessments and the grid rules, and the Naas scheme is at that stage now.

On the record we hold, and searching descriptions for the words 'data centre', no other data centre application covers the Naas lands. The only other Kildare filings that mention a data centre are commencement notices: two from 2024 for a control building and a 110 kV substation serving a data centre at Barnhall, Leixlip, and one from 2023 for a public sector data centre at Backweston.

Planning. Today an application goes to the local authority and can be appealed to An Coimisiún Pleanála. The Oireachtas Library and Research Service noted in March 2025 that section 49 of the Planning and Development (Amendment) Act 2018 adds large data centres, defined by land footprint, to the list of strategic infrastructure development; once commenced, applications for them would go directly to the Commission. We have not verified whether that has since been commenced. Large schemes typically need an Environmental Impact Assessment Report and, near protected sites, a Natura Impact Statement, as the Naas file does.

Grid connection. There is no moratorium on new data centres, but a data centre needs a grid connection contract before it is built, and the Dublin region has been capacity constrained. The Commission for Regulation of Utilities published its final connection policy for data centres in December 2025. Large data centres (10 MVA or more of import capacity) must provide dispatchable on-site or nearby generation or storage that matches their Maximum Import Capacity and takes part in the electricity market. Data centres of 1 MVA or more must meet at least 80% of annual demand with additional renewable electricity generated in the Republic, on a six-year glide path. The policy applies to new connection applications and replaces the 2021 direction.

Emissions licensing. On-site generation is what turns a data centre into an industrial emitter. Combustion installations with a total rated thermal input of 50 MW or more need an Industrial Emissions licence from the EPA. The Oireachtas research service counted about 13 licensed data centres in 2024.

Policy framework. The July 2022 Government statement and the January 2025 Large Energy User Action Plan set the direction: data centres should bring strong economic activity and jobs, use the grid efficiently, and be located and powered so that they add to renewable generation. The recast Energy Efficiency Directive requires data centres to report annually on energy use and environmental impact.

Climate law. The live legal argument in Naas is whether a planning authority must decide consistently with the national carbon budgets and Climate Action Plans. ClientEarth says it must. Whether the Commission agrees, and how it weighs the mitigation proposed, is the open question in this file.

The Central Statistics Office reported that data centres used 7,663 GWh of metered electricity in 2025, against 6,973 GWh in 2024 and 1,240 GWh in 2015. That is 23% of all metered electricity, up from 22% in 2024 and 5% in 2015. Residential use was 28% (18% urban, 9% rural). Data centre consumption grew 10% in 2025; all other users grew 2%.

The Oireachtas research service counted around 121 data centres run by 24 providers in March 2025, cited EirGrid's 2024 forecast that 89% of the growth in electricity needed over the next decade comes from data centres, and reported estimates that data centres account for between 2.5% and 4% of Ireland's greenhouse gas emissions. About 40% of Irish electricity came from renewables in 2023.

On our own register, 51 planning applications mention a data centre in their description: 32 in Fingal, 10 in South Dublin, 3 in Meath and one each in Kildare, Cork, Clare, Mayo and Westmeath. 31 are granted, 7 are recorded as commenced, 4 were refused and one, Naas, is under appeal. The register also holds 61 building-control commencement notices that mention a data centre: 28 in South Dublin, 18 in Fingal, 8 in Dublin City, 3 in Kildare, 2 in Meath and one in Cork. These count filings, not campuses: a single campus files many times.

The Department of Enterprise commissioned KPMG to value the sector and published 'The value of data centres to Ireland' on 2 June 2026. Its headline is that across the six sectors most dependent on data centres, over €100bn of annual gross value added, 875,000 jobs and €14.6bn a year in employment-related taxes are enabled by data centre capacity located in Ireland. For direct activity, it says construction and operation of data centres accounted for €2.2bn of GVA, 19,500 jobs and €280m of employment-related tax in 2024. The Department paid KPMG €104,938 for the work.

Supporters add that data centres anchor foreign direct investment and that the technology multinationals behind them bring significant corporation tax receipts, as the Oireachtas research service notes, and that energy analysts argue large electricity users could help balance a grid with more wind and solar. The same paper says that if the 2030 renewable targets are met, planned generation would cover the anticipated growth in data centre demand. A supplier trade association launched in February 2026 argues the benefits to Irish firms in the data centre supply chain are 'largely ignored'. The Naas design includes district heating, rooftop solar, rainwater harvesting and a biomethane injection point. Whether those offset its gas generation is the question the environmental assessments and the appeal now address.

MUSSI Working Paper 31, 'How we all pay for Big Tech: the social, economic and environmental costs of data centres in Ireland', is by Seán Fearon, Patrick Bresnihan and Patrick Brodie, published by the Maynooth University Social Sciences Institute in September 2026. It is a critical analysis and it argues for a moratorium on new data centre development. Its main claims, as the authors put them:

The economic case is exaggerated. They say the KPMG report rests on a flawed method: a survey of 30 large firms, an assumption that any business within 50 km of a data centre depends on it, and shares applied across whole sectors. They argue this creates a 'myth of domestic dependency' for activity that pre-dates data centres.

The sector is small in jobs and huge in power. They put direct permanent employment at about 3,300 and say data centres used 9.4 TWh, 23% of national grid demand, in 2025: about 144 jobs per 1% of national demand, against about 17,500 for the health sector. They calculate a data centre job as 776 times more electricity intensive than an education job, and 42 times more carbon intensive than the average job in the economy, at 620 tonnes of CO₂ per direct worker.

Costs land on the public. They cite modelling that data centres raised wholesale electricity costs by about €360 per average household between 2015 and 2023, some €715m in total, and argue that grid reinforcement costs are shared with households. They estimate the sector's water footprint, including the water used to generate its electricity, at about 125.9 million litres a day in 2025, equivalent to the direct water use of about 340,600 homes.

Opportunity cost. They estimate that nearly 50,000 homes could have been built between 2019 and 2024 with the capital invested in data centres, and warn of stranded assets if the AI investment cycle turns.

The paper is a working paper built on public data and stated assumptions, and several headline figures are the authors' own estimates rather than measured values. We have not found a published response to this paper from the Department or from the industry.

The camps are not counting the same thing. KPMG asks how much economic activity is 'enabled' by proximity to data centre capacity, and gets a very large, indirect number. The Maynooth authors ask how many people the sector employs directly, and how much electricity, water and carbon each of those jobs implies, and get a very small, direct one. Both can be arithmetically correct and still answer different questions.

Even the electricity figure has two bases. The CSO's 23% is a share of metered electricity consumption, and 7,663 GWh is the metered total. The Maynooth paper quotes 9.4 TWh and describes 23% of 'national grid demand', a broader base that we cannot reconcile from the published sources. Anyone quoting either should say which measure they mean. The same care applies to jobs: about 3,300 direct permanent jobs (Maynooth), 19,500 jobs in construction and operation (KPMG, 2024), and 875,000 'enabled' jobs (KPMG) are three different definitions.

The register records what was filed, when, by whom and what was decided. It does not record a scheme's real energy use, its water use, its jobs or its emissions; those come from the applicant's assessments, from regulators and from researchers, and they are contested in this case. It also cannot say how the Commission will weigh the climate argument. What it does show is that a contested scheme sits inside a much larger pattern: dozens of granted applications and more than sixty commencement notices in a sector using nearly a quarter of the country's metered electricity.