The Inner House of the Scottish Court of Session has delivered judgment in Raeshaw Farms Limited v Scottish Ministers [2026] CSIH 10, creating ripples in the energy sector.

The Court has quashed the grant of planning permission for a wind farm, holding that the construction of the wind farm and its connection to the electricity grid constituted a single project for the purposes of environmental impact assessment (EIA). The Court found that this had not been adequately assessed by the reporter.

 

What was the Court asked to consider?

The Court was asked to determine whether planning permission for a wind farm had been lawfully granted where the connection of the development to the electricity grid was not included within the planning application or environmental assessment. In particular, the Court considered:

• whether the construction of the wind farm and its grid connection constituted a single project for the purposes of assessing environmental impact; and
• whether the decision‑maker’s evaluation of that issue was sufficiently reasoned and fact‑specific.

 

 

The planning application

The planning application in question was granted on appeal and related to the construction of eight wind turbines, access tracks, a borrow pit, a temporary construction compound, a control building, an on‑site substation, associated infrastructure, and an energy storage compound.

The application concerned only the construction of the turbines and associated infrastructure. It did not include the future grid connection. The final details of the grid connection, including its precise route and any assessment of environmental impacts, were to be determined at a later stage by the local Distribution Network Operator (DNO) and might be subject to a separate design and consent process.

The Environmental Impact Assessment Report accompanying the application did not assess the impacts of the grid connection.

 

The planning appeal decision

At the planning appeal, the reporter rejected objections that the proposal amounted to “salami slicing” designed to avoid a full environmental assessment. The reporter concluded:

“Whatever grid connection solution is ultimately proposed will (if it requires planning permission) be subject to its own evaluation. It is not part of the current proposal. The objectors’ reference to the term ‘salami slicing’ is misdirected. That properly refers to an attempt to circumvent the objectives of the EIA Directive and regulations by dividing what is in reality a single project into separate parts. In this instance, there has been no attempt to avoid the need for an EIA. The development proposal has been subject to EIA in the normal way and if a subsequent proposal for a grid connection were EIA development, that too would require to be assessed in accordance with the EIA regulations.”

 

The Inner House of the Court of Session

One notable feature of the judgment is the Court’s detailed analysis of Irish case law on the assessment of grid connections associated with renewable energy projects. At paragraph 48, the Court acknowledged a divergence in focus between the UK and Irish courts but identified common themes, stating:

“While each member state will have transposed the 2011 Directive into its own national laws, that does not detract from the value of domestic courts considering the interpretative approach to the 2011 Directive taken by other states.”

 

Misdirection on the meaning of “salami slicing”

The Court found that the reporter had misdirected himself in his approach to salami slicing by focusing too narrowly on the scope of the application itself. This approach was held to be irrational:

“Further, and also materially, the reporter misdirected himself in relation to the definition of ‘salami slicing’ in a way that resulted in a failure to focus on the fundamental question of the interrelationship between the two phases of development and whether they both required an EIA at this stage.”

 

The need for a fact‑specific evaluation

The Court held that the reporter had failed to undertake the necessary fact‑specific evaluation of the proposal. What was required was a careful assessment of whether, on the available material, the wind farm construction and grid connection were so closely connected as to form parts of a single project.

Although the Court recognised that functional interdependence was plainly relevant—stating that “indisputably the windfarm could never become functional without a grid connection” (paragraph 46) – it emphasised that it was not for the Court itself to carry out the required evaluation (paragraph 47).

In considering whether a development is a standalone project or part of a wider project, the Court referred to R (Wingfield) v Canterbury City Council [2020] JPL 154. That case identified a non‑exhaustive list of relevant factors, including:

• common ownership;
• simultaneous determination;
• functional interdependence; and
• whether the development has stand‑alone project status.

At a minimum, this suggests that decision‑makers should undertake a Wingfield-type analysis when considering the extent of the project for the purposes of environmental assessment.

The Court concluded that the respondents’ position, that the reporter was entitled to assess the development on its own merits on the assumption that a grid connection would be provided at a later date, failed to address the underlying irrationality of considering only the merits, and not the demerits, of the completed development as anticipated.

The judgment further suggests that the proper approach is to assess the impacts of the grid connection as part of the cumulative environmental impact of the overall development.

 

Implications of the judgment

The judgment is not binding in Northern Ireland. However, as the dispute centred on the interpretation of the EIA Regulations, it is likely to be highly persuasive.

It is also important to note what the judgment does not say:

• it does not require grid connections to form part of every planning application for renewable energy development; and
• it does not require the environmental impacts of grid connections to always be assessed as part of the assessment of a renewable energy project.

For many developments, it may nonetheless be prudent to consider the potential environmental impacts of grid connections in combination with those of the renewable project itself within the EIA. A practical difficulty remains, however, where limited information is available regarding the nature or route of the grid connection at the application stage.

 

Conclusion

The judgment signals increased scrutiny of renewable projects where grid connections are deferred. Decision‑makers must carry out a reasoned, fact‑specific assessment of whether generating infrastructure and grid connection together form a single project for EIA purposes, particularly where functional interdependence is clear. While grid connections need not be included in every application, promoters cannot assume that postponing them avoids the need to consider their environmental effects, at least cumulatively. A failure to engage with this issue risks permissions being vulnerable to challenge.

 

For legal guidance and advice on how this judgement may apply to your business, please contact Maria O’Loan or another member of our Planning and Environment team.

While great care has been taken in the preparation of the content of this article, it does not purport to be a comprehensive statement of the relevant law and full professional advice should be taken before any action is taken in reliance on any item covered.