Webster & Anor v Meenacloghspar [Wind] Ltd; Shorten & Anor v Meenacloghspar [Wind] Ltd [No.2] (Approved)

Factual and Procedural Background

This case involves a nuisance claim brought by Plaintiffs against Company A, the operator of two wind turbines, one of which ("T2") was found in a principal judgment to cause a nuisance during night hours and quiet waking hours ("sensitive periods"). The court directed the parties to attempt mitigation measures prior to a second trial module. Company A trialled a single mitigation measure, restricting T2 to a lower power operational mode (the "1,600 mode"), which Plaintiffs contend did not abate the nuisance. Company A sought to adduce new evidence in Module 2 to revisit the liability finding from Module 1. This new evidence comprised an analysis of 2017 noise monitoring data by the defendant’s acoustician, relying on a recently published technical specification by the International Electrotechnical Commission (IEC). The court was tasked with determining the admissibility of this new evidence, the effectiveness of the mitigation trial, and the appropriate remedy.

Legal Issues Presented

1. Whether the new evidence adduced by the defendant should be admitted and whether the court should revisit its finding of liability made at Module 1.
2. Whether the mitigation measure trialled by the defendant (the 1,600 mode) abated the nuisance caused by T2.
3. Whether the plaintiffs are entitled to an injunction restraining the operation of T2, and if so, the precise terms and scope of such injunctive relief.

Arguments of the Parties

Defendant's Arguments

• The defendant argued that the new IEC technical specification constitutes new evidence that could not have been obtained with reasonable diligence for Module 1 and justifies revisiting the liability finding.
• The defendant contended that the new analysis of the 2017 noise data shows that wind turbine noise (WTN) levels, including amplitude modulation (AM) penalties, are below the limits prescribed by the 2006 Wind Energy Development Guidelines (WEDG 2006), excluding nuisance.
• It submitted that restricting T2 to the 1,600 mode during sensitive periods fully abated the nuisance.
• The defendant maintained that the plaintiffs should be confined to damages in lieu of an injunction.

Plaintiffs' Arguments

• The plaintiffs opposed the admission of the new evidence, arguing it could have been obtained with reasonable diligence for Module 1 and that the IEC does not fill the evidential gaps identified in the principal judgment.
• Plaintiffs contended the 1,600 mode did not abate the nuisance, supported by acoustic expert evidence demonstrating persistent intrusive noise characteristics including AM and thump AM.
• They argued that the defendant’s mitigation efforts were inadequate and that the nuisance caused serious and ongoing harm warranting injunctive relief rather than damages alone.
• Plaintiffs disputed the defendant’s interpretation and application of the Phase 2 penalty scheme and the relevance of WEDG 2006 as a determinant of nuisance.

Table of Precedents Cited

Precedent	Rule or Principle Cited For	Application by the Court
Murphy v. Minister for Defence [1991] 2 IR 161	Criteria for admitting new evidence to revisit a judgment: (1) evidence was not obtainable with reasonable diligence at trial; (2) evidence likely to have important influence on outcome; (3) evidence credible.	The court applied these criteria strictly and concluded the defendant failed to show the new evidence met them, thus rejecting the admission of the new evidence and refusal to revisit liability.
Greenwich Project Holdings Ltd v. Con Cronin [2021] IEHC 145	Strong reasons required to revisit a judgment.	The court found no strong reasons existed to reopen the principal judgment based on the new evidence.
Inland Fisheries Ireland v. O'Baoill [2015] IESC 45	New evidence in modular trials should only reopen earlier findings in exceptional circumstances to avoid undermining the modular trial process.	The court exercised caution and declined to reopen findings absent exceptional justification.
Hinde v. Pentire Property Finance DAC & Kavanagh [2018] IEHC 575	Two-element test for reopening judgments: evidence likely to influence result and credible; evidence could not have been presented with reasonable diligence at trial.	Applied to reject the new evidence as it could have been presented earlier.
Bailey v. Commissioner of An Garda Siochana [2018] IECA 63	First instance courts have jurisdiction to revisit issues decided in judgments only in exceptional circumstances or strong reasons.	The court found no exceptional circumstances to revisit the liability finding.
Emerald Meats v. Minister for Agriculture [2012] IESC 48	Trial is not a laboratory experiment allowing endless re-litigation; finality is important.	The court emphasized finality and rejected attempts to admit late evidence to alter findings.
Hanrahan v. Merck Sharp and Dohme (Ireland) Ltd [1988] ILRM 629	Burden of proof in nuisance cases lies on the plaintiff; defendants need not disprove nuisance.	The court held the defendant must prove that mitigation abates the nuisance, not the plaintiffs to prove nuisance anew.
Lanigan v. Barry [2016] 1 IR 656	Injunctions for nuisance require sufficient findings of fact to craft an appropriate remedy.	The court distinguished this case from Lanigan, finding sufficient facts to tailor an injunction.
Lawrence v. Fen Tigers Ltd [2014] 2 All ER 622	Once nuisance is established, injunction is prima facie appropriate; burden shifts to defendant to justify damages in lieu.	The court applied this principle to grant injunctive relief, rejecting confinement to damages.
Patterson v. Murphy [1978] ILRM 85	Damages in lieu of injunction only appropriate in exceptional circumstances; mere willingness to pay damages is insufficient.	The court held damages alone inadequate and granted injunction.
G v. A Judge of the District Court [2023] IEHC 386	Judges reviewing their own judgments should generally defer to the finality of written judgments unless exceptional reasons exist.	The court declined to revisit its prior judgment absent credible basis.
Bellew v. Cement Ltd [1948] IR 61	Public convenience generally not relevant to private nuisance rights but may be relevant to remedy.	The court considered public interest in crafting the remedy but did not allow it to override plaintiffs’ rights.
Fearn v. Board of Trustees of the Tate Gallery [2023] UKSC 4	Public interest may justify departure from strict injunction principles on remedy.	The court acknowledged public interest but found it did not outweigh the need to abate nuisance here.

Court's Reasoning and Analysis

The court undertook a detailed and rigorous analysis of the admissibility of the defendant’s new evidence, applying established principles from Irish case law concerning the admission of new evidence to revisit prior judgments. It found that the new evidence, consisting of an IOA Reference Method (IOA RM) analysis of 2017 noise data and its comparison with WEDG 2006 limits incorporating AM penalties, could with reasonable diligence have been obtained and presented at Module 1. The IEC technical specification, relied upon by the defendant as justification for late evidence, was held not to fill the evidential lacuna identified in the principal judgment, as it does not set noise limits or regulatory thresholds but merely provides measurement guidance. The court concluded that the IEC endorsement of the IOA RM was not a novel development justifying late admission.

Moreover, the court found that the new evidence, even if admitted, would not substantially alter the liability finding. The IOA RM analysis supported the court’s previous findings of significant and intrusive AM values and thump AM, which are key nuisances. The defendant’s reliance on the WEDG 2006 noise limits and the Phase 2 penalty scheme was rejected as misplaced, given that WEDG 2006 was not designed to address nuisance or AM, and the Phase 2 scheme remains under review and is not adopted in Ireland.

Regarding mitigation, the court found the defendant’s mitigation trial inadequate, having tested only one operational mode (the 1,600 mode) which failed to achieve a meaningful or perceptible reduction in nuisance. Acoustic evidence demonstrated that the 1,600 mode did not reduce AM or thump AM levels and only marginally reduced noise levels at windspeeds above 9 m/s, a change insufficient to abate nuisance. The court rejected the defendant’s argument that mitigation at this level sufficed.

On remedy, the court considered the principles governing injunctive relief in nuisance, emphasizing the plaintiffs’ prima facie entitlement to an injunction and the limited circumstances in which damages in lieu would be appropriate. It found the injury to the plaintiffs severe and ongoing, and that damages alone would not provide just relief. The public interest in renewable energy was acknowledged but did not outweigh the need to abate nuisance.

The court carefully tailored the injunction, balancing the need to abate nuisance with the public interest. It ordered shutdown of T2 during night hours and certain quiet waking hours at windspeeds and wind directions associated with high nuisance, while permitting restricted operation modes at other times where a 5 dB noise reduction could be reasonably achieved. The court rejected the defendant’s call for more precise scientific thresholds for nuisance, recognizing the multifactorial and intermittent nature of WTN nuisance and the practical limitations of such precision.

Holding and Implications

The court refused to admit the defendant’s new evidence and declined to revisit the prior finding of liability. It found that the 1,600 mode mitigation trial did not abate the nuisance caused by T2 and granted an injunction restraining the operation of T2 during sensitive periods as follows:

• Shutdown of T2 at night (23:00 to 07:00) and quiet waking hours (18:00 to 23:00 and specified daytime periods) at windspeeds of 5 m/s to 11 m/s inclusive, except in certain wind directions where nuisance was not found.
• Restricted operation to lower power modes during quiet waking hours at specific windspeeds where a 5 dB noise reduction is predicted and achievable.
• Operation permitted at highest windspeeds (12 m/s and above) with appropriate mode restrictions at night due to expected masking by wind noise.

The injunction is crafted to minimize nuisance while recognizing the public interest in renewable energy generation. The court emphasized the defendant’s failure to engage constructively in mitigation and noted that any difficulties arising from the injunction are self-inflicted. No new legal precedent was set; rather, the decision applies established principles to the specific factual context of wind turbine noise nuisance and mitigation.