Nationally Significant Infrastructure Projects: Technical Advice Page for Scoping Solar Development
Source: gov.uk (2025-03-27)

This page provides technical advice on the consideration of scope in the Environmental Impact Assessment Process for solar Nationally Significant Infrastructure Project (NSIP) development.

The government has published guidance about national infrastructure planning which applicants, members of the public and other parties should read. See the National Infrastructure Planning Guidance Portal. (https://www.gov.uk/government/collections/national-infrastructure-planning-guidance) The guidance should be read alongside the Planning Act 2008 (https://www.legislation.gov.uk/ukpga/2008/29/contents) (the Planning Act).

This advice is non-statutory. However, the Planning Inspectorate’s advice about running the infrastructure planning regime and matters of process is drawn from good practice and applicants and others should follow our recommendations. It is intended to complement the legislation, regulations and guidance issued by government and is produced under section 51 of the Planning Act.

This advice should be read together with Planning Inspectorate’s Advice on the Environmental Impact Assessment Process (https://www.gov.uk/government/collections/national-infrastructure-planning-advice-notes), Commitments Register and government guidance on the Planning Act process (https://www.gov.uk/government/collections/national-infrastructure-planning-guidance-portal).

Advice Context

This advice has been prepared having regard to matters raised on previous NSIP applications and has been informed by the policy tests set out within the relevant National Policy Statements EN-1, EN-3 and EN-5 2024, the requirements of the Infrastructure Planning (Environmental Impact Assessment) Regulations 2017, and the requirements of the Infrastructure Planning (Applications: Prescribed Forms and Procedure) Regulations 2009.

Please note that this advice does not relate to the Habitats Regulations Assessment process. Please see the Planning Inspectorate’s Advice on the Habitats Regulations Assessment process (https://www.gov.uk/government/collections/national-infrastructure-planning-advice-notes).

This advice addresses the scoping stage for solar development in the Planning Act 2008 NSIP process and will be expanded in future to cover later stages of the Planning Act 2008 process.

The Inspectorate considers that this advice, if followed, will help enable smoother, more efficient NSIP examinations, with fewer issues needing to be addressed during the examination, and will assist Examining Authorities, applicants and stakeholders to better concentrate their resources.

This advice complements the Planning Inspectorate’s tiered pre-application service (https://www.gov.uk/guidance/nationally-significant-infrastructure-projects-2024-pre-application-prospectus#:~:text=The%20introduction%20of%20three%20pre-application%20tier%20options%20reflecting), and is of particular benefit to projects opting for the basic level of service from the Planning Inspectorate, where applicants have opted for limited project specific advice.

An NSIP is likely to possess unique issues and present opportunities that are best identified using an evidence-based approach. Each Development Consent Order (DCO) application will be considered according to its own merits. For this reason, this advice is:
- not overly prescriptive
- not entirely comprehensive in terms of the topics and matters identified to be addressed within an application
- does not override the position reached in an applicable Environmental Impact Assessment (EIA) scoping opinion, or that of an Examining Authority during the examination of an application
However, this advice is intended to support greater proportionality in the assessment process and should be viewed as informing the starting point for the development of DCO applications, and particularly the EIA and Environmental Statement.

Technical Advice for Scoping Solar NSIP Development

By applying a comprehensive, evidence-based approach to EIA scoping, certain aspects or matters can be scoped out of the EIA, ensuring that the emphasis of the Environmental Statement is on the likely ‘main’ or ‘significant’ environmental effects anticipated. This provides for more focussed resource allocation in pre-application for all parties, and increased clarity to all involved in the process.

The Solar Scoping Table (https://assets.publishing.service.gov.uk/media/671649c1583ef2380ad997f8/Solar_Scoping_Table__2_.odt) (ODT, 16.5 KB) included in this advice, provides examples of supporting information that can assist the Planning Inspectorate when considering whether to agree to scope aspects (as defined within the EIA regulations and sometimes referred to as environmental ‘factors’ or ‘ topics’) and / or matters (a sub-division of an aspect, such as a specific impact or receptor type) out of the EIA for solar NSIP developments.

The Solar Scoping Table focuses on some select examples of aspects / matters where significant effects are unlikely to occur for a typical solar development or where they can be controlled through the implementation of standard mitigation measures such that a significant effect on the environment is not likely to occur. It sets out the type of evidence, assumptions and commitments that should be provided at the scoping stage to demonstrate that significant effects are not likely.

The information provided in the Solar Scoping Table comprises examples only. It does not take into account specific information in relation to the project and its receiving environment, and therefore does not guarantee that the Planning Inspectorate will be able to agree to scope certain matters out of the assessment in all cases. Such decisions will be based on the specifics of each project, the receiving environment, the validity and robustness of the supporting information provided, and the responses of advice from consultees.

The list of aspects / matters outlined in the Solar Scoping Table is not intended as an exhaustive list, and it may also be possible to scope other aspects / matters out of the EIA where there is sufficient evidence to conclude that a significant effect is unlikely to occur.

The decision by the Planning Inspectorate on whether to agree to scope an aspect or matter out of the EIA is subject to the provision of appropriate supporting information accompanying a scoping request to give confidence that there is little or no likelihood of a significant effect.

In general terms, the type of information that may be provided in support of a request to scope aspects / matters out of the EIA may include information on the environmental baseline, the proposed development, and potential impact pathways that could arise because of the proposed development.

This information may include certain assumptions that form the basis for conclusions within the scoping report, for example assumptions around construction techniques or vehicle movements. All assumptions that underpin the case to scope aspects / matters out of the EIA should be clearly set out in the scoping request in a tabular format that can then be tracked throughout the process.

Subsequent iterations of this table should be produced within the Preliminary Environmental Information Report (PEIR) and the Environmental Statement submitted alongside the DCO application.

The case for scoping certain aspects / matters out of the EIA may also be supported by the provision of information to describe commitments that the applicant is confident will form part of the proposed application at submission, such as the application of industry standards or to implement tried and tested mitigation measures.

Where the case to scope aspects / matters out of the EIA is based on a commitment to providing mitigation, the scoping request should include adequate information on the proposed measures to demonstrate that they are capable of being secured and implemented, and that there is a high level of confidence in the success / effectiveness of those measures. This could include evidence of previous success and / or agreement from relevant consultation bodies.

Commitments should be recorded in a first iteration of a Commitments Register to be submitted as part of the scoping request, and confirmed in an updated version of the Commitments Register to be submitted as part of the DCO application.

Where commitments are made to implement certain mitigation measures, the scoping request and Commitments Register should identify which outline control document these will be included within, and how they will be secured. Please see the Planning Inspectorate’s advice on the Commitments Register (https://www.gov.uk/government/collections/national-infrastructure-planning-advice-notes) for a template and further information on its intended use within the NSIP planning process.

Assumptions and commitments should be verified before submission and confirmed in the application documents. If subsequently the assumptions or commitments set out in the scoping request change and could result in different environmental effects, this would not adhere to the agreed scope and may undermine any agreement to scope a matter or aspect out.

Early engagement with the relevant consultation bodies in advance of a scoping request can help to enable agreement on the scope of the EIA. Where evidence of agreement with relevant consultation bodies on the scope of assessment (for example, evidence to support scoping matters out, baseline surveys, approach to assessment and mitigation) can be provided within the scoping request, this may assist the Planning Inspectorate in determining whether to scope aspects / matters in or out of the assessment.

Whilst this advice identifies the type of information required in support of scoping aspects or matters out of the EIA, it is also important that the scope of any assessments of aspects or matters to be included within the EIA is scoped proportionately.

For example, the use of a well-defined and evidence-based study area can be used to identify those receptors that have the potential to be affected by the proposed development. Those where no pathway exists or where the magnitude of any impact would be so low that a significant effect would be unlikely to occur, and that can therefore be scoped out of the assessment.

This advice does not specifically address the scoping of cumulative effects. Where an applicant is considering whether to seek to scope an aspect or matter out of the EIA on the basis that the project alone would not result in a likely significant effect, consideration should also be given to the potential for likely significant effects in cumulation with effects resulting from other projects (as set out in the Inspectorate’s advice on Cumulative Effects Assessment) (https://www.gov.uk/guidance/nationally-significant-infrastructure-projects-advice-on-cumulative-effects-assessment).

Where the potential for a cumulative effect is identified through scoping or later in the EIA process, the Environmental Statement will need to include adequate information to inform an assessment of those potential cumulative effects.

In all cases where a National Policy Statement either has effect or may be important and relevant, matters which are scoped out of the Environmental Statement but where a National Policy Statement test of process or outcome is required then that test must still be evidenced.

This evidence can include material which was used to scope a matter / aspect out, plus any relevant further evidence and this should be clearly shown in a summary of policy compliance, a planning statement or the equivalent, and be submitted as part of the application.

Example of how the information in the Solar Scoping Table should be applied

An example is provided to demonstrate how the information identified within the Solar Scoping Table (https://assets.publishing.service.gov.uk/media/671649c1583ef2380ad997f8/Solar_Scoping_Table__2_.odt) (ODT, 16.5 KB) may be applied within the scoping request, when presenting the case to scope an aspect / matter out of the EIA.

The example below demonstrates how information concerning the anticipated number and type of vehicle movements, vehicle routing and the outline description of certain environmental management measures, could be applied in support of a case to scope out vehicle and / or dust emissions from the air quality aspect of the EIA. This is only where there is a high degree of confidence that the scale and nature of works would not result in a likely significant effect on the environment.

Example

Applicants should set out the following traffic related information within the scoping request:
- the confirmed or assumed number of vehicle movements for each vehicle type, for example, heavy goods vehicles (HGVs) and light goods vehicles, during construction, operation and decommissioning. Where assumptions are being made, the scoping request should explain how these have been determined. For example, reference to typical transport movements known to be associated with certain activities
- any available information on the planned approach to site access and vehicle routing, or commitments to minimise the impact of traffic on the road network through measures such as avoiding movements at certain times of the day, avoiding routing through sensitive areas or distributing vehicle movements through the use of multiple site access points. Where these assumptions inform the case to scope this matter out, they should be recorded within the Commitments Register document in order that they can be validated at the submission stage
- a high level description of the road network that is likely to be affected, in terms of the extent, characteristics and any known traffic hotspots or problem areas
- the potential effects resulting from traffic or construction works. For example, temporary generation of dust soiling within 500m of the site boundary arising from construction works
- a high-level outline of the types of standard / good practice environmental management or mitigation measures that the applicant is committed to securing through the DCO and implementing post-consent. This could constitute a list of bullet points to illustrate the type of good practice measures envisaged and a commitment to implementing those measures in accordance with the guidance and specifications prescribed within a specified industry good practice documents. For example, site-specific mitigation will be designed and implemented in accordance with measures and specifications set out in the Institute of Air Quality Management (IAQM) 2023 guidance. This would include implementation of a dust management plan to be incorporated within the Outline Construction Environmental Management Plan secured by way of a requirement in the DCO. An example of measures to be set out in the dust management plan includes wheel washing facilities at site exits to be used by all HGVs exiting the site, the erection of solid screens around dusty activities
- in general, the Planning Inspectorate will place limited reliance on comparison with other developments when drawing conclusions on whether a significant effect is likely to occur. This is because the specifics of each project and the context of the receiving environment are likely to differ between projects. However, such information may form part of the Planning Inspectorate’s consideration. Where applicants seek to place reliance on experience from other projects to support scoping matters/aspects out, then an explanation of how or why this experience is considered applicable to the current project should be provided along with supporting evidence
- a conclusion on whether there is the potential for a likely significant effect. It is not considered that a detailed level of assessment would be required or available at the scoping stage. Therefore, following the presentation of the relevant information as set out above, the scoping request should present a structured and objective consideration of the likely magnitude of impact resulting from traffic or construction activities, and consideration of the likelihood that any effects would exceed relevant thresholds set out within the appropriate industry guidance. It should draw on the information above and specifying the extent to which any expert judgment has been applied. For example, thresholds for requiring detailed assessments or determining the level for a significant effect
In some cases, it is possible that certain effects, whilst not likely to be significant and therefore not needing to be addressed within the Environmental Statement, may require a level of information or evidence to support consideration by an Examining Authority when addressing the policy tests set out within the relevant National Policy Statements.

This information may be satisfied in part by the information included at the EIA scoping stage to support the scoping of aspects or matters out of the EIA. Where this is the case and such information is to be relied upon to address the tests set out in the relevant National Policy Statements, then applicants will need to track and validate this information to ensure that it remains accurate and sufficient at the point of submission.

Applicants may also determine a need to provide additional information (beyond that provided within the scoping request) to support the consideration of policy tests relating to environmental matters outside of the scoping request and Environmental Statement, within other documents or as part of standalone reports.

The information required to address policy tests should be clearly identified within the DCO application documents, making use of a ‘policy compliance document’ (where submitted) to signpost where in the application supporting evidence and / or information is provided.

Where applicants intend to provide information within the application regarding environmental matters that are to be scoped out of the EIA, and this is known at the scoping stage, then it is useful for the scoping request to set out how and where this information will be provided within the DCO application.

Where the information provided within the application documents is not sufficient to satisfy policy tests or to adequately examine principal issues, then it will be at the discretion of the Examining Authority whether to request additional evidence or information during an examination.

Supporting Technical Assessments to the Environmental Statement

The following aspects are not considered to require separate chapter assessments in a solar development Environmental Statement. This is because typically these relate to a source of an impact that could occur to receptors that are considered under a number of different environmental aspects, for example, lighting may be a consideration for both landscape and visual assessment and also for ecology.

These technical assessments should therefore be provided as appendices to the Environmental Statement and cross-referred to where relevant within individual aspect assessments.

Glint and Glare

Following the mapping of potentially sensitive receptors, the scoping request should consider the geometric possibility for a glint and glare impact to occur. Where the potential for such an impact is identified, a glint or glare assessment should be undertaken.

This should be provided as a technical assessment to be included as an appendix to the Environmental Statement and, where there is potential for a likely significant effect, should inform the assessment of effects within the relevant chapters, such as landscape and visual, traffic and transport.

This should apply appropriate modelling and predictive techniques, charts/ diagrams and visual representations (such as GIS-based viewshed analyses) to indicate the likely extent and distance of potential glint and glare and should be informed by the following project description parameters:
- panel height
- panel directionality
- panel design/type, for example tracker panels
- panel locations and extent
- identification of sensitive receptors, for example public rights of way and airports
- where any proposed mitigation is secured
Electro-Magnetic Fields (EMF)

Where proposed cables are over 132kV, an EMF assessment should be provided in an appendix to the Environmental Statement. This should include the location, routing and voltages of any cables over 132kV and a risk assessment to any human and ecological sensitive receptors within the ZoI.

Lighting

A separate chapter assessment is not expected for lighting, however, this should be assessed within other relevant chapters including landscape and visual, cultural heritage and ecology where there is potential for a likely significant effect. It is expected that these chapters are supported by appropriate lighting strategies addressing lighting requirements during construction, operation and decommissioning (where appropriate), and including information on:
- directionality
- spill
- locations
- type
- heights
- duration and timing e.g. any night-time lighting during construction through winter months
- intensity and output e.g. LUX
- method of control, for example infrared, automation
- identification of sensitive receptors, for example bats, nearby residential dwellings
- where the proposed lighting and any mitigation measures are secured