Grid Connections, Environmental Assessment and the DCO Process – What is the effect of the Raeshaw Farms judgement?

A recent judgment in Scotland highlights the need for those promoting energy projects to consider carefully how the project’s grid connection should be considered in the environmental assessment of the proposals.

In Raeshaw Farms Ltd v Scottish Ministers [2026] CSIH 10, the Inner House of the Court of Session quashed a decision to grant planning permission for an eight-turbine wind farm, holding that the reporter had committed a material error by failing to conduct a fact-specific evaluation of whether the wind farm and its grid connection constituted a single project for Environmental Impact Assessment (EIA) purposes (so that the grid connection should also have been assessed).

The judgement considered the Irish authority of Ó Grianna v An Bord Pleanála [2014] IEHC 632, in which the court held that the turbine development and grid connection comprised a single project and observed that, where a developer argues the grid connection is too uncertain to assess, this is "rather suggestive of permission being sought prematurely".

However, the Inner House instead endorsed Baker J's view in the Irish High Court in Daly v Kilronan Windfarm Limited [2017] IEHC 308 that it cannot be said in absolute terms that the only permissible way to apply for planning permission is to include the grid connection. Reference was made to the endorsement in the Court of Appeal of a "staged approach" to assessment, in R (Together against Sizewell C Ltd) v Secretary of State for Energy Security and Net Zero [2023] EWCA Civ 1517, which recognised that such an approach could prevent "sclerosis in the planning system".

Whilst the NSIP regime under the Planning Act 2008 in England operates differently from the Town and Country Planning (Scotland) Act 1997 regime at issue in Raeshaw, many wind generation projects in the UK have in practice adopted a common approach to this issue. In Raeshaw the court heard testimony that in planning applications or appeal processes for 28 separate onshore windfarm projects within the UK, none had assessed in detail the potential impact of the off-site grid connection as part of the windfarm project. Similarly, energy NSIPs have often proceeded through examination and been granted a Development Consent Order (DCO) despite the grid connection details not being fully finalised at the point of decision. It may be, for example, that the grid connection infrastructure is to be delivered by a third party (e.g. National Grid) under a separate consent and sufficient details are unknown. Support for inclusion of the grid connection as part of the project may be found in relevant NPS guidance, where it is stated that “..wherever reasonably possible, applications for new generating stations and related infrastructure should be contained in a single application to the Secretary of State or in separate applications submitted in tandem which have been prepared in an integrated way..”.  The wording implies however that this will not be possible in every case.

Nonetheless, even when faced with a single application for a windfarm, the decision maker must consider whether the windfarm is part of a larger project for EIA purposes. The court in Raeshaw concluded that an adequate assessment had not been done and it was not for the courts to step in. 

Therefore, what course of action should promoters of energy NSIPs adopt to combat a Raeshaw based EIA objection?

First, there is an interconnection between the latest Connections Reform process and the DCO process.  Due to the limited capacity of the national grid, the National Energy Systems Operator (NESO) now determines if or when an energy project may be connected to the grid based on a “first ready and strategically needed, first connected” approach rather than the “first come, first served” approach adopted prior to 2025. This has reordered the queue for connections with some project connection dates being pushed well into the late 2030s. To provide some certainty that a scheme will be connected to the grid in a timely manner and to avoid any arguments of prematurity of the scheme, it is important for EIA purposes to evidence the status of the grid connection process and its progression trajectory in the DCO application. In the context of the reformed connections regime, this would mean explaining the timetable for applying for and obtaining an offer, and how the project intends to secure a firm connection.

Second, for EIA purposes, relying solely on a staged consenting approach (whereby the EIA of the grid connection will come later) may be problematic unless for example the connection infrastructure consenting process is being undertaken in tandem, and therefore in a timely manner, (for instance by National Grid) and will be subject to its own separate consent with its own EIA and a cumulative assessment will be undertaken at that stage.

Third, if it is unknown whether there will be a future EIA , then during scoping of the EIA for the main project, consideration should be given to what is known about the grid connection and how the EIA might address those works. The Environmental Statement could for example identify the likely connection point and route, contain an assessment of the potential environmental effects of the connection works (for example by looking at the reasonable worst-case under the Rochdale Envelope approach) and consider cumulative effects of the generating station and connection together.  

For the Secretary of State to rely on the benefits of an NSIP once connected (e.g. more renewable electricity generation, contribution to net zero) as weighing in favour of consent, the Secretary of State would also need to consider the potential environmental disbenefits of the grid connection that would be needed to deliver those benefits. Environmental assessment of the grid connection avoids the risk of challenge on this point.

In summary, whilst the Raeshaw judgment does not automatically render a DCO application with uncertain grid connection details "premature", it does highlight the need to scrutinise carefully how the environmental effects of the grid connection are to be addressed for any renewable energy NSIP. The structural interplay between the Connections Reform regime and the DCO process is an area where policy and case law are not yet fully aligned, and applicants would be wise to address the grid connection issue head-on in their applications.