Keogh and Ors v An Coimisiun Pleanala and Anor (Approved)

Factual and Procedural Background

The judgment was delivered by Judge Humphreys in proceedings brought by three local objectors (hereafter "Plaintiff 1", "Plaintiff 2" and "Plaintiff 3", collectively "Plaintiffs") against the planning decision-maker (hereafter "Defendant") challenging the grant of planning permission to the developer (hereafter "Company A") for a seven-turbine wind energy development in four townlands in County Carlow. The planning application was lodged with the planning authority on 13 May 2024 and refused by the authority on 5 July 2024. Company A appealed; an Inspector reported recommending permission; the Defendant granted permission by order dated 27 November 2025 subject to 24 conditions. The Plaintiffs commenced judicial review proceedings on 20 January 2026, obtained leave, filed amended grounds, and the matter was heard on 27 April and 5 May 2026. Judgment was reserved and a draft circulated to parties on 22 May 2026. The Court dismissed the proceedings and ordered a recital confirming that the second named plaintiff's dwelling is not a "participating property" for the purposes of Condition 9(a).

Legal Issues Presented

1. Whether the Defendant lawfully complied with EIA/AA obligations in respect of the development (including cumulative noise, landscape/visual impacts and traffic safety).
2. Whether the Defendant lawfully had regard to and treated development plan policy (alleged material contraventions) in deciding to grant permission.
3. Whether the Defendant lawfully had regard to or improperly fettered its discretion by treating the 2006 Wind Energy Guidelines as determinative (and related SEA-related complaints).
4. Whether submissions of the Plaintiffs (including on microplastics and the misdescription of a dwelling as a "participating property") were considered and if any failure of consideration or reasons arose.
5. Procedural/contention issues about the admissibility and weight of late/replying affidavit evidence and whether unpleaded arguments (notably invoking s.15 of the Climate Action and Low Carbon Development Act 2015) could be relied on.

Arguments of the Parties

Plaintiffs' Arguments

• The Defendant failed to carry out a full EIA and did not address likely significant effects on human amenity (particularly cumulative night-time noise), landscape/visual impacts and traffic safety.
• The Defendant failed to consider relevant planning history (including a prior refusal) and failed to give reasons as to why the present proposal differed materially from that prior refusal.
• The Defendant improperly treated the 2006 Wind Energy Guidelines as prescriptive, and should have applied more recent guidance (2019 draft), WHO 2018 noise guidance, and expert reports.
• The Defendant ignored submissions on microplastics and misdescribed the second plaintiff's property as a "participating property", producing a material factual error affecting mitigation (shadow flicker).
• The Plaintiffs relied on an expert affidavit/report filed late (Huson) to challenge the EIA/noise assessment.

Defendant's Arguments

• The Defendant and Inspector properly considered all relevant material (including the EIAR, NIS, planning authority reports and submissions) and reached reasoned conclusions; reasons and main issues were addressed to the requisite standard.
• The EIAR and Inspector's report addressed noise (including AM and low frequency issues), landscape and traffic; the Defendant adopted and applied those reasoned conclusions.
• Allegations based on unpleaded legal grounds (including s.15 of the 2015 Act) were not raised on the pleadings and cannot be relied on; the Plaintiffs bear the onus of proof to displace the presumption that material was considered.
• The misdescription of the second plaintiff's dwelling in Company A's material was an error of the applicant's documentation only and Condition 9 and related mitigation apply to the dwelling; a recital or clarification in the order suffices.
• Late replying affidavit evidence was procedurally improper and, in any event, should be afforded no weight; conflicts of evidence resolve against the Plaintiffs absent cross-examination.

Company A's Arguments

• Company A submitted that the EIAR was adequate, that cumulative and technical issues were assessed, and that the Plaintiffs have not adduced expert evidence to overturn the Inspector's technical conclusions.
• Company A contended the mislabelling of the second plaintiff's property was de minimis, harmless, and in any event would be remedied by interpreting Condition 9 to apply to the dwelling.
• Company A joined the Defendant in submitting that unpleaded collateral challenges to the validity of Government guidelines (SEA point) cannot be advanced in these proceedings without joining the State and that the have-regard status of s.28 guidelines limits the Plaintiffs' argument.

Table of Precedents Cited

Court's Reasoning and Analysis

The Court proceeded by applying established principles drawn from Irish and EU caselaw concerning (i) the limits of judicial review (legality not merits), (ii) stringent pleading requirements, (iii) the onus of proof on applicants to establish defects in EIA/AA by admissible evidence, (iv) the standard for reasons (main reasons on main issues), (v) the evaluative margin accorded to planning decision-makers, and (vi) the discretionary nature of certiorari.

Applying those principles the Court dealt with each core ground:

• Preliminary procedural points: the Court held unpleaded invocation of s.15 of the Climate Act was not part of pleaded grounds and could not be relied on; late/replying affidavit evidence (Huson) was procedurally problematic and, even if admitted, carried no weight where it conflicted with contemporaneous material before the Defendant and the Inspector's report.
• Planning history (Core Ground 2): the Court found the Inspector's Report and the Defendant's Order expressly engaged with past applications and permitted developments; a prior refusal did not automatically preclude permission for a different proposal in a changed factual and policy context.
• Wind energy guidelines and noise/shadow flicker (Core Ground 3): the Court held the Inspector and Defendant had regard to the 2006 Guidelines while also considering more recent material; Plaintiffs failed to discharge the onus to show the Defendant treated the guidelines as prescriptive or that the noise/AM assessments were legally defective.
• Misdescription of the second plaintiff's property (Core Ground 5): the Court concluded the error lay in Company A's documentation and did not affect the operation of the planning condition; Condition 9 and related mitigation applied to the dwelling and a recital in the order would clarify this.
• Material contravention of the development plan (Core Ground 6): the Court analysed the plan provisions, noted tensions between different policies (some supporting renewables), accepted the Inspector's sophisticated analysis of plan/national policy interaction, and held the plan provisions left evaluative judgment to the Defendant; no material contravention was demonstrated.
• EIA/AA and specific technical claims (Core Grounds 1 and 4): the Court emphasised that alleged scientific or technical shortcomings must be established by admissible expert evidence. The Plaintiffs did not discharge that onus; the EIAR, Inspector's report and Defendant's Order set out the assessments and conclusions which, unless displaced by evidence, were presumed considered and adequate.
• SEA challenge to 2006 Guidelines (Core Ground 7): the Court treated any collateral attack on the validity of the Guidelines as impermissible in these proceedings absent joinder of appropriate State parties and concluded that s.28 "have regard to" guidance did not amount to a framework for development consent that would trigger SEA.
• Discretion: even if an error had been established the Court applied discretionary principles (conduct of Plaintiffs, practical value of remedy, proportionality and public interest in renewable infrastructure) and concluded certiorari would be inappropriate.

Holding and Implications

DISMISSED

Holding: The Court dismissed the Plaintiffs' judicial review proceedings in their entirety. It ordered that a recital be included confirming that the second named plaintiff's dwelling is not a "participating property" for the purposes of Condition 9(a), and otherwise ordered dismissal of the proceedings with no order as to costs unless otherwise applied for as directed.

Implications: The immediate effect is that the Defendant's grant of planning permission (27 November 2025) remains effective and Company A may proceed subject to the conditions. The Court applied established principles on pleading, onus of proof, reasons, evaluative deference in planning matters, and discretion; it did not establish a novel legal principle or depart from cited jurisprudence. Where claimants rely on technical or scientific defects in EIA/AA they must adduce timely admissible expert evidence and properly plead legal bases; collateral attacks on non-binding guidelines require appropriate State joinder.