The Supreme Court has reserved judgement in an appeal against a decision by An Bord Pleanála to approve the first phase of a data centre in Athenry, Co Galway.
Apple was given permission to construct the facility in 2016 but last year abandoned plans to proceed with the development.
Two objectors appealed to the Supreme Court, after the High Court dismissed their challenge to the planning board’s decision.
The appeal was brought by Sinead Fitzpatrick, who lives near the proposed data centre, and Allan Daly of Athenry.
Today’s hearing came after the Supreme Court issued a judgment setting out the precise issues to be addressed in the appeal last December.
The court had to first decide on these issues because An Bord Pleanála had complained that different issues were being pursued in the Supreme Court to those argued in the High Court by the objectors.
The Chief Justice, Mr Justice Frank Clarke, said the central thrust of the appellants' case related to the extent to which the board was obliged to assess the environmental impact of the balance of the Apple "masterplan" for eight data halls, as part of the board's obligation to carry out an environmental impact assessment (EIA).
Why is the Irish planning system so complex?
In his opening submission, Michael McDowell, SC for the appellants, said the appeal centred on whether An Bord Pleanála should have carried out and EIA relating to the entire masterplan for the site in question.
He drew attention to a number of plans, showing the potential of the site to facilitate a total of eight data centres in due course.
Mr McDowell said this was a major development, involving the purchase and conversion of a 500 acre site outside Athenry.
While it had sought permission for the construction of a 24,000 square metre data centre, an electrical substation and some ancillary buildings, Apple’s masterplan for the site envisaged an additional seven data halls.
It is Mr McDowell’s contention that An Bord Pleanála should have taken all this into account, instead of just adjudicating on the application for a single data centre.
He said the computer company’s approach was an exercise in "project splitting" that allowed it to avoid consideration by the board of the wider impact of its plans, by limiting the application to one data centre.
He said a central issue for the court was that the An Bord Pleanála inspector had stated clearly that the development could not be justified were it just to consist of one hall and ancillary works. In other words, the only basis was that the entirety of what was planned would be built in due course.
Mr McDowell also drew attention to the application for a 240 mega volt electrical substation, that would take up 20 acres. He said this was "wholly excessive" for a single data centre and could only be justified for a total of eight data halls.
He said the planning board had failed to consider the whole masterplan in reaching its decision.
Mr McDowell said it was very "knowable" what was being envisaged and it was not possible to regard the application for one data centre as a stand alone project.
The "foot in the door" argument was extremely important here.
Insofar as it was practicable to do so, Mr McDowell said An Bord Pleanála should have carried out an EIA that would encompass the suitability of the site for eight centres as well as looking at the issues that arose from such significant energy consumption.
In her submission, Nuala Butler SC, for the board, said the appellants' approach was legally wrong, as the planning board could not attach conditions to a consent that had not been applied for.
In essence, she said Ms Fitzpatrick and Mr Daly wanted a snapshot of the 2016 situation to be treated as a "freeze frame" in relation to energy issues for the entire eight data centre masterplan.
She said the inspector's report into the application pointed out that there was uncertainty regarding energy supply, which would need to be analysed as part of any future planning application.
While it was presumed in principle that the site was suitable for more than one data centre, there were no presumption that all phases would be approved.
In terms of energy issues, Ms Butler said the Environmental impact of a 240 mega watt demand on the National Grid depended firstly on the ability of the grid to supply that, as well as the climate effects of that amount of energy being used.
Ms Butler said the rollout of the overall masterplan was linked to the demand for data storage, which in turn was based on predicted demand over the next fifteen to twenty years.
It was always the case that it would be an incremental development as the need for data storage increased.
But she said there were lots of planning reasons why An Bord Pleanála should not be granting permission for something that probably will - but may or may not be needed - in 2030.
Planning permissions are granted for five year terms for deliberate reasons, one of them to ensure that a situation doesn't develop where long standing approval can be in conflict with other planning policies.
She also took issue with the contention that the decision making process put the potential for employment, as a result of the development, over other concerns.
An analysis of the "downstream generation of jobs from this kind of development" showed there would be spin off employment from the data centre, regional impact and rolling construction jobs over a number of years.
But she said there was no "binary trade-off" between climate concerns and employment prospects as a result of the development.