Site-Specific Conservation Objectives Are Required When Screening Protected Sites Within a Delimited Zone of Impact

1. Introduction

This judgment clarifies an important distinction in environmental assessment: identifying the geographical area that a development might affect is not the same exercise as deciding whether individual protected sites within that area may experience significant effects.

Applying a preliminary ruling of the Court of Justice of the European Union (“CJEU”), the High Court held that An Coimisiún Pleanála had erred when it excluded effects on the Blackwater Callows Special Protection Area (“SPA”) without site-specific conservation objectives. The commission had already accepted a screening report delimiting a 15 km zone of impact, within which the SPA lay.

The applicant challenged permission granted to Curns Energy Limited for the 17-turbine Lyrenacarriga wind farm and associated infrastructure. However, by this sixth judgment, the refusal to quash that permission was final. The outstanding question was whether the applicant should receive a further declaration identifying an error in the appropriate assessment screening process.

The court granted that declaration. It did not invalidate the planning permission. The decision therefore addresses both the proper sequence of environmental screening and the availability of declaratory relief for a legal error previously found to be harmless.

2. Background and Procedural Setting

The development and protected site

Curns Energy Limited applied for development consent in January 2021 under section 37E of the Planning and Development Act 2000. Its application included an environmental impact assessment report, an appropriate assessment screening report and a Natura impact statement. Following consultation, further information and an inspector’s recommendation, permission was granted on 8 November 2023 under section 37G.

The Blackwater Callows SPA, designated in 2012, lies approximately 9.9 km north of the development. Its protected interests include Whooper Swan, Wigeon, Teal, Black-tailed Godwit, and wetland and waterbirds. Generic conservation objectives had been adopted in January 2022, but site-specific objectives were not adopted until March 2024, after permission had been granted.

The developer’s screening methodology initially identified European sites within 15 km and also considered connectivity with more distant sites. The inspector concluded that significant effects could be excluded for the Blackwater Callows SPA, relying on matters including:

• the absence of hydrological connectivity;
• the lack of suitable wintering habitat within the development site;
• the absence of several protected bird species from the surveys;
• only one recorded Whooper Swan observation; and
• the development’s location outside the species’ identified 5 km core foraging range.

The actual screening decision did not exclude every European site from further assessment. Three other sites proceeded to appropriate assessment. The present dispute concerned the exclusion of the Blackwater Callows SPA.

Why only declaratory relief remained

In the second judgment, the High Court rejected the claim for certiorari—the order that would have quashed the permission—but granted two declarations concerning other legal shortcomings. It preserved the conservation-objectives issue solely as a possible basis for further declaratory relief.

Attempts to obtain permission to appeal were unsuccessful. The fifth judgment subsequently clarified that the refusal to quash was final, while the claim for a declaration remained live. The CJEU reference therefore concerned an outstanding remedy, not an opportunity to reopen the validity of the permission.

Following the CJEU’s judgment of 16 July 2026, the High Court had to determine whether the screening exercise fell within the circumstances in which site-specific conservation objectives were required.

3. Summary of the Decision

The court’s principal conclusions were:

1. Geographical delimitation can sometimes occur without site-specific conservation objectives. Objective criteria may establish, with the certainty required by the precautionary principle, that protected sites outside the delimited area cannot be affected.
2. Assessment of sites within that area requires those objectives. Once the relevant geographical area has been identified, the probability or risk of significant effects on protected sites within it must be assessed by reference to their site-specific conservation objectives.
3. The commission made a legal error. Having accepted the developer’s 15 km zone of impact, it excluded effects on the Blackwater Callows SPA within that zone without the necessary objectives.
4. The error justified a declaration, not quashing. Its harmlessness had already been reflected in the final refusal of certiorari. That did not prevent the court from formally identifying the error.
5. Costs should provisionally follow success on the declaration. Recovery was confined to the costs attributable to that successful issue, rather than the wider unsuccessful challenge.

4. The Governing Legal Framework

Screening and appropriate assessment

Article 6(3) of the Habitats Directive establishes the relevant assessment framework. Screening asks whether a plan or project requires a fuller appropriate assessment because of its possible significant effects on a protected European site.

The CJEU explained that screening is not intended to reproduce the complete and precise analysis required at the appropriate assessment stage. Nevertheless, where screening examines possible significant effects on a protected site within the relevant geographical area, it must use the conservation objectives specific to that site.

Why site-specific objectives matter

Conservation objectives provide the ecological benchmark against which effects are evaluated. Identifying a protected species, or referring generally to maintaining favourable conservation status, is not necessarily equivalent to identifying what must be maintained or restored at the particular site.

The judgment treats the absence of site-specific objectives as legally significant even where other scientific evidence supports the eventual screening outcome. The correctness of an outcome and compliance with the legally required assessment framework are distinct questions.

The geographical exception

Paragraph 81 of the CJEU judgment permits some preliminary cataloguing and exclusion without site-specific objectives. Distance and the existence or absence of plausible impact pathways may establish that certain sites cannot be affected, regardless of their particular objectives.

Paragraph 82 provides the contrast: for sites within the geographical area likely to be affected, the probability or risk of significant effects cannot be assessed without considering their site-specific conservation objectives. The High Court’s reasoning turned on the relationship between those two paragraphs.

5. Detailed Analysis of the Court’s Reasoning

A. The parties disagreed about the scope of the geographical exception

The applicant argued that the Blackwater Callows SPA was within the development’s identified zone of impact. Accordingly, the CJEU ruling required site-specific objectives to inform the decision whether significant effects could be excluded.

The commission, supported by the State respondents and developer, argued that inclusion in an initial search area did not establish that a site was actually within the area likely to be affected. On their interpretation, the authority could provisionally catalogue a site and subsequently exclude it using objective evidence of distance, absent connectivity and unsuitable habitat, without site-specific objectives.

The commission also relied on the earlier, final factual findings that there was no reasonable possibility of an impact on the SPA. Those findings, it submitted, brought the case within the CJEU’s permitted exclusion process.

B. The court distinguished geographical delimitation from individual-site assessment

Humphreys J. rejected the respondents’ interpretation. The decisive distinction was between:

• delimiting the geographical area that the project is likely to affect; and
• assessing possible effects on individual protected sites within that area.

In the court’s reading, paragraph 81’s references to distance and plausible impact pathways were expressly connected to the first exercise. They did not create a general permission to undertake detailed exclusions of individual sites inside an already delimited area without site-specific objectives.

The court described the geographical exclusion as an exception to the general insistence on those objectives. Reading it as authorising unrestricted site-by-site exclusion would, in its view, undermine the contrast expressly drawn in paragraph 82.

This was a contested interpretation, not merely an undisputed application of terminology. The High Court expressly acknowledged that a broader pathway-based exclusion rule might have been sensible, but concluded that it was not the rule the CJEU had adopted.

C. The accepted 15 km zone was decisive on these facts

The commission had adopted the inspector’s screening assessment, which drew on the developer’s report. The court treated that acceptance as delimiting a 15 km zone of impact. The Blackwater Callows SPA was plainly within it.

Its subsequent exclusion therefore belonged to the individual-site assessment stage. Since site-specific objectives did not exist at the relevant time, that exclusion involved a legal error.

The judgment does not establish a universal 15 km assessment radius. The ministerial guidance reproduced in the judgment distinguishes between plans and projects. For projects, the relevant distance may be much shorter, depending on the development, ecological receptors and possible cumulative effects; connectivity may also require consideration beyond 15 km. The significance of 15 km here arose from the geographical area accepted in this particular screening exercise.

D. The court did not overturn its scientific findings

The earlier findings concerning the lack of a reasonable possibility of impact remained intact. The applicant had not displaced the relevant expert evidence, and the refusal to quash had become final.

The declaration did not contradict those findings. It identified a defect in the legal framework used to reach the screening conclusion. Thus, the court could simultaneously accept that the missing objectives made no material difference on the evidence and hold that the assessment should legally have referred to them.

E. Harmless error could still be declared

The court reiterated that a legal error does not automatically require certiorari. Where an error has been shown not to produce effects contrary to EU law, a declaration may be the appropriate remedy.

Here, harmlessness had already justified refusing to quash. The court considered that using the same consideration to refuse a declaration would be inappropriate in the unusual procedural circumstances: the possibility of declaratory relief had been the express basis for maintaining the preliminary reference.

The resulting declaration was specific. It identified the commission’s exclusion of effects on the Blackwater Callows SPA within the accepted zone without site-specific objectives. Although the applicant had sought wording referring to conservation objectives “and/or measures”, the operative order concerned objectives. The judgment should therefore not be treated as establishing that conservation measures are invariably required for every screening decision.

6. Precedents and Authorities Cited

A. The controlling European ruling

Joined Cases C-27/25 (Knocknamona) and C-356/25 (Massey), ECLI:EU:C:2026:596, supplied the governing interpretation of EU law. Its central contribution was the distinction between preliminary geographical exclusion and the assessment of protected sites within the relevant area. The present judgment applies that distinction to the commission’s accepted 15 km zone.

The judgment also records Advocate General Kokott’s Opinion in Joined Cases C-27/25 and C-356/25, ECLI:EU:C:2026:315. However, the operative domestic reasoning rests on the CJEU’s judgment; the supplied text does not separately analyse or adopt propositions from the Opinion.

Eco Advocacy, C-721/21, EU:C:2023:477, appears within the CJEU passage reproduced by the High Court. It explains why measures designed to avoid or reduce significant effects belong at appropriate assessment rather than screening: considering them too early risks bypassing an essential safeguard. Its relevance here is structural. It reinforces the distinction between the preliminary screening exercise and the fuller assessment, rather than independently determining the geographical issue.

B. Earlier decisions in the same litigation

• Massey v. An Bord Pleanála & Ors. (No. 1) [2021] IEHC 783 concerned the strategic infrastructure designation and rejected that challenge. It explains the development’s procedural background but did not decide the conservation-objectives question.

• Massey v. An Bord Pleanála & Ors. (No. 2) [2025] IEHC 206 was foundational. It refused certiorari, granted other declarations, made the relevant factual findings and preserved the possibility of further declaratory relief. Its final findings constrained the scope of the sixth judgment.

• Massey v. An Bord Pleanála & Ors. (No. 3) [2025] IEHC 218 formally made the preliminary reference. Its statement that an affirmative answer would support a declaration was relied on by the applicant. The sixth judgment nevertheless examined the CJEU’s qualified answer and the facts rather than treating that statement as an unconditional entitlement to relief.

• Massey v. An Bord Pleanála & Ors. (No. 4) [2025] IEHC 309 refused certification for an appeal under section 50A(7) of the 2000 Act. Its importance lies in the procedural finality surrounding the refusal to quash.

• Massey v. An Bord Pleanála [2025] IESCDET 126 refused leave to appeal. The commission relied on its observations concerning the uncontested evidence that the absence of objectives made no difference. The present judgment respected that finality while distinguishing harmlessness from the existence of an error.

• Massey v. An Bord Pleanála & Ors. (No. 5) [2025] IEHC 709 clarified that the reference remained relevant because declaratory relief was still pending. That explanation materially supported granting a declaration after the CJEU’s answer, notwithstanding the final refusal of certiorari.

C. Other environmental proceedings

Friends of Ardee Bog v. An Bord Pleanála & Ors. [2025] IESCDET 29 and Friends of Ardee Bog v. An Bord Pleanála & Ors. [2025] IESC 13 prompted further submissions during the earlier hearing. The supplied judgment does not reproduce their substantive reasoning, so they should be understood here as influences on the procedural development of the issue, not as separately articulated foundations for the present holding.

Punchestown Area Community Group v. An Bord Pleanála [2024] 431 JR involved a similar issue. Questions were circulated to its parties, but the proceedings were later compromised. It supplied related submissions, not an adjudicated precedent relied on for the outcome.

Commission v Ireland C-444/21 was invoked by the applicant to place the State’s failure to adopt conservation objectives in a wider enforcement context. It supported the applicant’s public-importance argument; the High Court did not use it as the immediate legal basis for the declaration.

D. Costs authorities

Little v The Chief Appeals Officer [2024] IESC 53 was relied on in support of costs even if the applicant failed. Because the applicant obtained a declaration, that alternative argument did not require decision. The judge’s provisional view was that this case did not meet the exceptional-public-importance threshold for awarding an unsuccessful applicant costs. The decision therefore does not recognise an automatic entitlement to costs merely because litigation produces useful clarification.

Hoctor v An Coimisiún Pleanála (No.1) [2026] IEHC 65 was cited by the commission in seeking a set-off of its costs of resisting certiorari against the applicant’s costs award. The court provisionally declined that approach, considering the public importance of the successful issue sufficient, on balance, to weigh against set-off. It did not treat the cited decision as compelling the same result in every case.

E. Draft-judgment procedure authorities

The judgment also addresses circulation of drafts under Practice Direction HC 137. These authorities concern procedure, not the conservation-objectives holding:

• O'Sullivan v. Health Service Executive [2023] IESC 11 supports the warning that draft circulation does not create an entitlement to elaborate additional procedures.
• O'Sullivan v. Sea Fisheries Protection Authority [2017] IESC 75, [2017] 3 I.R. 751, [2018] 1 I.L.R.M. 245 supports the rejection of the assumption that fairness always requires procedures approximating a criminal trial.
• Attorney General v. Crosland (No. 2) [2021] UKSC 58, [2022] 1 W.L.R. 367 is expressly identified as explaining why restrictions on publication of draft judgments serve the administration of justice.
• Baigent v. Random House Group Ltd [2006] EWHC 1131 (Ch); R. (Counsel General for Wales) v. Secretary of State for Business, Energy and Industrial Strategy [2022] EWCA Civ 181; Public Institution for Social Security v. Banque Pictet & Cie SA and others [2022] EWCA Civ 368; and Itkin v. Wood [2023] JRC 101 are additionally cited in connection with draft confidentiality. Their individual reasoning is not developed in the supplied judgment.

Together, these procedural references support a controlled opportunity to identify errors and ambiguities, not a fresh hearing or permission to publish a draft.

7. Costs and the Limits of the Order

The substantive declaration was granted. The proposed costs arrangements were subject to any party applying by written submissions within seven days.

The proposed award against the commission included relevant reserved costs, written submissions, CJEU proceedings and legal costs adjudication. However, it was expressly limited to costs that would have been incurred had the applicant confined the case to the successful relief.

It excluded unsuccessful factual disputes and wider claims not vindicated by the CJEU ruling. The judgment also preserved the earlier position that there was no order as to costs associated with the unsuccessful certiorari claim.

This is significant: success in securing an important declaration did not convert the entire litigation into a successful challenge. The court separated the costs of the vindicated legal issue from those of the failed attempt to invalidate permission.

8. Likely Impact and Practical Significance

Clearer separation of screening tasks

Planning authorities and developers should distinguish the initial delimitation of the potentially affected area from subsequent assessment of individual sites. Under this judgment, an accepted zone of impact has legal consequences: sites within it cannot simply be removed through detailed pathway analysis conducted without site-specific objectives.

Greater importance of precise reports

The decision encourages clarity about whether an area is merely an initial search envelope or the geographical area actually delimited as potentially affected. Labels cannot replace ecological analysis, but the authority’s adoption of a report may establish what assessment framework it has accepted.

No universal distance rule

The judgment neither makes every site within 15 km vulnerable to significant effects nor permits automatic exclusion beyond that distance. Delimitation remains project-specific and must account for ecological connectivity and the precautionary principle.

State obligations and decision-maker obligations remain distinct

The State’s responsibility for establishing conservation objectives does not eliminate the planning authority’s obligation to apply the correct screening framework. Earlier declarations addressed State failures; the present declaration identified the commission’s separate error.

Remedies remain sensitive to facts and finality

The decision does not establish that missing objectives automatically invalidate permission. It demonstrates that a declaration may vindicate an environmental-law requirement while permission remains intact because the error was harmless and the refusal to quash is final.

The broader importance of the case lies in this combination: rigorous identification of the legal requirement, without treating every breach as necessarily requiring the most disruptive remedy.

9. Complex Concepts Simplified

Appropriate assessment screening

The preliminary decision whether possible significant effects on a European site require a fuller ecological assessment.

Site-specific conservation objectives

The particular ecological goals for a protected site, used as the benchmark for evaluating potential effects.

Geographical delimitation

Identifying the area a project might affect before assessing the protected sites within it.

Impact pathway

A plausible connection through which a development could affect a protected feature—for example, water movement or bird movements.

Precautionary principle

The requirement for adequate certainty before excluding environmental risks, rather than treating uncertainty as proof of safety.

Certiorari

A court order quashing a public authority’s decision. It was finally refused in this litigation.

Declaration

A formal judicial statement identifying the legal position or an error, without itself quashing the decision.

Harmless error

A legal defect shown, on the relevant evidence, not to have produced a material consequence requiring the decision to be set aside.

Costs set-off

Deducting one party’s recoverable costs from costs otherwise payable to the other party.

10. Conclusion

The High Court held that the commission could not exclude effects on the Blackwater Callows SPA within its accepted 15 km zone of impact without site-specific conservation objectives. The limited ability to delimit an affected geographical area without those objectives did not authorise detailed exclusions of individual sites inside it.

The resulting declaration left the planning permission untouched. The judgment’s central significance is therefore twofold: it requires a disciplined sequence in ecological screening, while confirming that an established but harmless legal error can be formally recognised without quashing the underlying consent.