Wind Farm EIAs: Grid Connections Require a Fact-Specific “Single Project” Evaluation (and Reasons)

1. Introduction

Raeshaw Farms Limited appealed under section 239 of the Town and Country Planning (Scotland) Act 1997 against a decision of a Scottish Ministers’ reporter granting planning permission for Wull Muir Wind Farm, promoted by Energiekontor UK Ltd (interested party). The wind farm application covered eight turbines and associated on-site infrastructure, but did not include the off-site grid connection.

The central legal issue was whether, for the purposes of environmental impact assessment (EIA), the wind farm and its grid connection could lawfully be treated as separate, or whether they were in reality a single “project” whose cumulative environmental effects required assessment before permission was granted. A related issue was whether the reporter’s reasoning on “salami slicing” (project splitting) and on the need for a cumulative assessment was legally adequate.

2. Summary of the Judgment

The Inner House (Lady Wise delivering the Opinion) held that the reporter committed material legal errors in dealing with the grid connection issue and in providing reasons. In particular:

  • The reporter failed to conduct the necessary fact-specific evaluative exercise to decide whether the wind farm and grid connection formed a single project for EIA purposes.
  • The reporter misdirected himself by treating “salami slicing” as turning on an attempt to circumvent the EIA regime, whereas the authorities show the focus is on the objective effect of splitting on environmental assessment.
  • The reasons given (a single paragraph) were inadequate, amounting largely to assertion and failing to demonstrate that the live issue had been understood and resolved on a legally correct basis.
  • There was force in an associated irrationality challenge: it is potentially irrational to attribute weight to the benefits dependent on the grid connection (renewable generation, climate benefits, socio-economic benefits) without addressing the corresponding adverse impacts of the completed scheme to the extent possible.

The court therefore quashed the reporter’s decision dated 14 January 2025 and remitted the appeal to a different reporter for a fresh decision.

3. Analysis

3.1 Precedents Cited

(a) CJEU authorities on “project” and cumulative assessment

  • Bund Naturschutz v Freistaat Bayern (Case C-396/92) [1994] ECR I-3717
    The court drew support from Advocate General Gulmann’s influential analysis: EIA must, as far as practicable, take account of planned extensions and the broader context so that environmental effects are considered “at the earliest possible stage”. Although the ECJ’s decision ultimately turned on transitional provisions, the Opinion was treated as persuasive in framing the purpose-led approach to defining the relevant “project”.
  • Commission v Spain (Case C-227/01) [2005] Env LR 20; [2004] ECR I-8253
    A core authority for the proposition that the Directive’s objectives cannot be undermined by splitting a scheme into smaller parts. Critically, the Inner House relied on the principle that the benchmark is not subjective intention but whether a project is likely to have significant environmental effects—supporting the court’s conclusion that the reporter erred by treating salami slicing as requiring an “attempt” to circumvent the EIA regime.
  • Umweltanwalt von Kärnten v Kärntner (Case C-205/08) [2010] Env LR 15; [2009] ECR I-11525
    Reinforces that ignoring cumulative effects must not lead to projects escaping assessment in practice where, taken together, they are likely to have significant effects. This underpinned the court’s insistence that the reporter had to grapple with the cumulative effects question rather than defer it by reference to a possible later application.

(b) Scottish authorities

  • Skye Windfarm Action Group v Highland Council [2008] CSOH 19
    Used to illustrate a fact-sensitive approach to whether elements can be assessed separately. The Lord Ordinary accepted that integral parts “should not normally be considered in isolation”, but upheld separation in that case because earlier assessment had not identified significant effects from borrow pits and a cumulative assessment had in any event been sought and considered. The Inner House treated this as supporting the need to examine the “particular circumstances”.
  • Wildland v Highland Council [2021] CSOH 87; 2022 SLT 1082
    Distinguished. There, postponement of assessment of visitor facilities was rationally justified by uncertainty (e.g., exclusion zone not clarified) and it was clear that a further planning application would follow, at which stage cumulative impact would be assessed. Here, by contrast, the reporter proceeded on the basis that it was unknown whether planning permission and/or EIA would be required for the grid connection, which made a careful “single project” evaluation more—not less—important.
  • West Lothian Council v Scottish Ministers [2023] CSIH 3; 2023 SLT 175
    Provided the benchmark for adequacy of reasons: decisions must identify the live issues and make clear what considerations were taken into account. The court held paragraph 129 of the reporter’s decision did not meet that standard.

(c) England & Wales authorities on defining the “project” and staged assessment

  • R (Wingfield) v Canterbury City Council [2020] JPL 154
    Central to the Inner House’s critique: Lang J’s non-exhaustive factors (common ownership; simultaneous determinations; functional interdependence; stand-alone justification) were approved elsewhere and were the kind of structured evaluative approach the reporter failed to undertake. The Inner House emphasised that “functional interdependence” was plainly relevant because the wind farm cannot function without a grid connection.
  • R (Ashchurch Rural Parish Council) v Tewkesbury BC) [2023] EWCA Civ 101; [2023] Env LR 25
    Key authority used twice: (i) “project” must be understood “broadly, and realistically”; (ii) intention to circumvent is not required; (iii) irrationality may arise if benefits of a wider scheme are weighed without assessing corresponding adverse effects where possible. The Inner House used this to support both the legal error on salami slicing and the force of the appellant’s irrationality argument.
  • R (Finch) v Surrey County Council [2022] EWCA Civ 187; [2022] Env LR 27 and [2024] UKSC 20; [2024] 4 All ER 717
    Although not directly on grid connections, the Supreme Court’s discussion of Directive interpretation reinforced that validity requires a systematic and comprehensive assessment of likely significant effects before decision, and that public participation is integral—values undermined if a decision-maker too readily treats an essential component as outside scope without proper evaluation.
  • R (Together against Sizewell C Ltd) v Secretary of State for Energy Security and Net Zero [2023] EWCA Civ 1517; [2024] Env LR 22
    Cited for the legitimacy, in principle, of staged/cumulative assessment “as soon as” cumulative effects can be meaningfully assessed. The Inner House did not reject staged approaches generally; rather, it held the reporter failed to decide (on the facts) whether staging was lawful and compliant given the uncertainty about whether grid works would later be subject to EIA.

(d) Republic of Ireland authorities on wind farms and grid connections

  • Ó Grianna v An Bord Pleanála [2014] IEHC 632
    Treated as strong persuasive reasoning: wind farm and grid connection were “one project” because neither serves a purpose without the other; therefore their cumulative effects should be assessed for compliance. The Inner House agreed that Irish courts’ Directive-focused approach is valuable, while stopping short of adopting an absolute rule that applications must always include the grid connection.
  • Daly v Kilronan Windfarm Limited [2017] IEHC 308
    Emphasised that while consent routes may differ, EIA is required for the whole project; parts cannot be separated and treated as exempt so as to defeat Directive objectives.
  • Sweetman v An Bord Pleanála [2023] IEHC 89 and North Westmeath Turbine Action Group v An Bord Pleanála 2025 IEHC 608
    Reinforced the Irish line that EIA must address the entire project, and that screening of a part does not substitute for a compliant EIA where a full-project EIA is required.
  • An Taisce - The National Trust for Ireland v An Bord Pleanála (Kilkenny Cheese Ltd, Notice Party) [2022] IESC 8; [2022] 2 IR 173
    Not directly in point on its ratio, but referenced as recognising that some off-site activities can have a “clear and unbreakable inter-relationship” with the project for assessment purposes—Ó Grianna being an example.

(e) Comparative EU material

  • Asociación Ambiental e Cultural Petón do Lobo v Dirección Xeral de Planificación Enerxética e Recursos Naturais (Do Lobo Environmental and Cultural Association v Directorate General of Energy Planning and Natural Resources), Judgment 00368/2025
    A Galician decision supporting the view that turbines and associated power line/grid feed are components of a single wind farm project requiring a single environmental impact statement in that application.

3.2 Legal Reasoning

(a) The correct legal question: what is the “project” for EIA?

The statutory appeal was rooted in EU Directive 2011/92/EU (as amended) and the Town and Country Planning (Environmental Impact Assessment) (Scotland) Regulations 2017. The Directive requires assessment of direct and indirect significant effects, with emphasis on considering effects at the earliest possible stage.

The Inner House held the reporter’s analysis never properly addressed the legally prior question: whether, on the facts, the wind farm and its grid connection were so closely connected that they formed a single project for EIA purposes, such that cumulative effects required consideration before granting permission for the turbines.

(b) “Salami slicing” is about objective effect, not intention

The reporter treated “salami slicing” as properly referring to an attempt to circumvent the EIA regime. The court held this was a misdirection: the authorities emphasise the practical consequence of splitting (whether it undermines the Directive’s purpose), not the developer’s motive. This error mattered because it diverted the reporter from the required inquiry into interrelationship, functional dependence, and cumulative effects.

(c) Staged approaches can be lawful, but only after evaluative justification

The court accepted that staged assessment may be legitimate in principle (as reflected in the authorities discussing avoiding “sclerosis”), and endorsed the view that it cannot be stated in absolute terms that every wind farm application must include grid connection detail. However, staging must be justified through a proper evaluation of whether cumulative effects can be meaningfully assessed later, and—crucially in this case—whether a later EIA is even likely to occur, given the reporter’s acceptance that it was unknown whether the grid solution would require planning permission.

(d) Adequacy of reasons: why the single paragraph failed

Paragraph 129 of the decision:

  • did not show that the reporter had identified the real issue (single project/cumulative assessment);
  • rested on assertion (“not part of the current proposal”) rather than legal evaluation;
  • invoked an incorrect intention-based definition of salami slicing;
  • offered an opaque assurance that the grid connection would be “subject to its own evaluation” without addressing whether that satisfied the Directive’s “earliest possible stage” requirement on the facts.

Applying West Lothian Council v Scottish Ministers [2023] CSIH 3; 2023 SLT 175, the reasons did not adequately disclose what considerations were taken into account and why the objection was rejected.

(e) The associated irrationality point

The reporter gave “positive weight” to operational benefits (renewable generation and climate change mitigation), which are dependent on a grid connection. Drawing on R (Ashchurch Rural Parish Council) v Tewkesbury BC) [2023] EWCA Civ 101; [2023] Env LR 25, the court considered there was force in the submission that it is irrational to take benefits that presuppose the wider/completed scheme without considering adverse impacts of that completed scheme to the extent possible. The point reinforced the practical difficulty of treating the wind farm and grid connection as analytically separate when the planning merits case is advanced on the basis of their combined operational outcome.

3.3 Impact

  • Decision-makers must explicitly evaluate “single project” arguments: A bare statement that the grid connection is not in the application is not enough. Reporters must demonstrate a structured, fact-specific evaluative judgment on interrelationship and cumulative effects.
  • Intent is not the test for salami slicing: Scottish EIA practice should align with the objective-effects approach reflected in the cited CJEU and UK authorities.
  • Greater pressure to address grid connection uncertainty: Where it is unknown whether later grid works will require planning permission and/or EIA, the risk of non-compliance increases if the turbines are consented first without cumulative assessment.
  • Reasons scrutiny in EIA cases remains demanding: While not “conveyancing” scrutiny, EIA decisions must show the live issue has been properly understood and answered.
  • Practical development implications: Developers may need to provide more information on likely grid connection options (even if not finalised) to enable meaningful cumulative assessment, or clearly justify a staged approach by reference to what can realistically be assessed at each stage and when.

4. Complex Concepts Simplified

EIA / “Environmental impact assessment”
A pre-permission process requiring the developer to supply an EIA report and the decision-maker to reach a reasoned conclusion on likely significant environmental effects, so the public can participate on an informed basis.
“Project” (Directive) / “Development” (Regulations)
The real-world scheme to be assessed. It may be broader than the boundaries of a single planning application if parts are functionally and environmentally connected.
“Salami slicing” / project splitting
Dividing what is in substance one scheme into separate parts so that the overall environmental effects are never properly assessed. The key question is the effect on the EIA process, not whether the developer meant to avoid scrutiny.
“Cumulative effects”
The combined environmental impacts of connected components or phases taken together, which may be greater or different than each part considered alone.
Wednesbury rationality
A public law standard of review: the court does not remake the planning judgment, but can intervene if the decision-maker’s evaluative judgment is irrational or legally flawed (including failure to ask the right question).
Staged / multi-stage assessment
Sometimes environmental assessment can properly proceed in phases (e.g., where detail is not yet knowable), but only if cumulative effects will be assessed as soon as they can be meaningfully identified, and without undermining the Directive’s purpose.

5. Conclusion

The Inner House’s decision establishes that, in Scottish EIA practice, a reporter must not treat exclusion of an off-site grid connection from a wind farm application as determinative. The reporter must instead undertake (and explain) a fact-specific evaluation of whether the wind farm and grid connection are a single project requiring assessment of cumulative effects at the permission stage, particularly where it is uncertain whether later grid works will be subject to any EIA process. The judgment also clarifies that “salami slicing” is not intent-based and reinforces that reasons must demonstrate real engagement with the live EIA issue. The remedy— quashing and remit to a different reporter—signals the centrality of lawful scoping and reasoning to the integrity of environmental decision-making.