6. Environmental Impact Assessment Methodology

6.1. Introduction

1. This Offshore Environmental Impact Assessment (EIA) Report has been developed to support an application for consent for the Proposed Development (under Section 36 of the Electricity Act 1989) and relevant Marine Licences (under the provisions of Part 4 of the Marine (Scotland) Act 2010 and Part 4 of the Marine and Coastal Access Act 2009)[1], in accordance with the requirements of the following regulations (collectively referred to hereafter as the EIA Regulations):

• in respect of a Section 36 consent application: The Electricity Works (Environmental Impact Assessment) (Scotland) Regulations 2017; and
• in respect of a marine licence application: The Marine Works (Environmental Impact Assessment) (Scotland) Regulations 2017 and The Marine Works (Environmental Impact Assessment) Regulations 2007.
  2. Volume 1, chapter 2 provides further details on the EIA Regulations and a detailed description of the Proposed Development can be found in volume 1, chapter 3.
  3. This chapter of the Offshore EIA Report presents the EIA methodology used for the assessment of likely significant environmental effects of the Berwick Bank Wind Farm Offshore infrastructure (hereafter the ‘Proposed Development’) seaward of Mean High Water Springs (MHWS), on physical, biological and human environment receptors.
  4. The Applicant has prepared a separate Onshore EIA Report in respect of a planning application for the onshore elements of the Project under the Town and Country Planning (Environmental Impact Assessment) (Scotland) Regulations 2017 which provides a description of the EIA methodology followed for the onshore elements of the Project (landward of Mean Low Water Springs (MLWS)).
  5. The Applicant is also developing an additional export cable grid connection to Blyth, Northumberland (the Cambois connection). Applications for necessary consents (including marine licences) will be applied for separately. The Cambois connection has been included as a cumulative project for the purposes of this Offshore EIA Report and is based on information presented in the Cambois connection Scoping Report (SSER, 2022e), submitted in October 2022. A separate EIA and Habitats Regulation Appraisal (HRA) will be prepared to support the Cambois connection consent applications which will also consider cumulative effects with the Proposed Development.
  6. This chapter presents:
• the assessment methodology used to determine potential impact including the approach that has been used to assess magnitude, sensitivity of receptors and conclusion on the likely significance of effect;
• the methodology used for assessing cumulative effects assessment (CEA);
• the methodology for assessing inter-related effects; and
• the methodology for assessing transboundary effects.
  7. Each topic chapter also contains further topic specific methodologies where appropriate. These are explained further within the relevant Offshore EIA Report chapters (volume 2, chapters 7 - 21).

6.2. Environmental Impact Assessment Legislation and Guidance

8. In compliance with the European Union (EU) Directive on the assessment of the effects of certain public and private projects on the environment (EIA Directive) (2011/92/EU, as amended by Directive 2014/52/EU) and the EIA Regulations, when applying for Section 36 consent or a marine licence, an EIA Report is required to be prepared and submitted to support these applications if the Proposed Development is likely to have a significant effect on the environment due to factors such as its size, nature or location.
9. The assessment of effects methodology employed in this Offshore EIA Report draws upon relevant legislation, policy and guidance, including those listed below:

• Council Directive 2011/92/EU of 13 December 2011 on the assessment of the effects of certain public and private projects on the environment, as amended by Council Directive 2014/52/EU (the EIA Directive);
• The Electricity Works (Environmental Impact Assessment) (Scotland) Regulations 2017;
• The Marine Works (Environmental Impact Assessment) (Scotland) Regulations 2017, the Marine Works (Environmental Impact Assessment) Regulations 2007 and Marine Licensing (Pre-application Consultation) (Scotland) Regulations 2013;
• The Conservation (Natural Habitats &c.) Regulations 1994 – applies in Scotland, extending to Scottish inshore waters (0 nm to 12 nm);
• The Conservation of Habitats and Species Regulations 2017 – only applies in Scotland for specific activities (reserved matters) including consent applications under Sections 36 and 37 of the Electricity Act 1989;
• The Conservation of Offshore Marine Habitats and Species Regulations 2017 - applies to the Scottish offshore region (beyond 12 nm);
• The Wildlife and Countryside Act 1981;
• Marine Scotland Consenting and Licensing Guidance: For Offshore Wind, Wave and Tidal Energy Applications (Marine Scotland, 2018);
• The Design Manual for Roads and Bridges (DMRB) LA 104: Environmental assessment and monitoring (Highways Agency et al., 2020);
• Guidelines for Ecological Impact Assessment (EcIA) in the UK and Ireland – Terrestrial, Freshwater, Coastal and Marine (CIEEM, 2019);
• A Handbook on Environmental Impact Assessment: Guidance for Competent Authorities, Consultees and Others Involved in the Environmental Impact Assessment Process in Scotland (NatureScot, 2018);
• Environmental Impact Assessment for Offshore Renewable Energy Projects (British Standards Institute (BSI), 2015);
• Guidelines for data acquisition to support marine environmental assessments of offshore renewable energy projects (Centre for Environment, Fisheries and Aquaculture Science (Cefas), 2012);
• A Review of Assessment Methodologies for Offshore Wind Farms (Collaborative Offshore Wind Research into The Environment (COWRIE) METH-08-08) (Maclean et al., 2009);
• IEMA Environmental Impact Assessment Guide to Shaping Quality Development (IEMA, 2015);
• UK Planning Inspectorate Advice Note Nine: Rochdale Envelope (PINS, 2012); Advice Note Twelve: Transboundary Impacts (PINS, 2015); and Advice Note Seventeen: Cumulative Effects Assessment(PINS, 2019);
• The Conservation of Habitats and Species (Amendment) (EU Exit) Regulations 2019 (HM Government, 2019a); and
• The Marine Environment (EU Exit) (Scotland) (Amendment) Regulations 2019 (HM Government, 2019b)).
  10. Where relevant topic specific guidance and legislation exists, this is discussed within the relevant Offshore EIA Report chapters (volume 2, chapters 7 to 21).
  11. References to legislation in this Offshore EIA Report are to the relevant legislation as amended.

6.3. Consultation

12. Consultation on the proposed offshore EIA methodology (including the CEA methodology and approach to assessing transboundary and inter-related effects) was undertaken at the offshore EIA scoping stage. The Berwick Bank Wind Farm Offshore Scoping Report (SSER, 2021a) presented these methodologies and requested feedback on the proposed approaches. A summary of the key issues raised during consultation relating to this chapter are outlined below in Table 6.1   Open ▸ , together with how these issues have been considered in the production of this chapter.

Table 6.1: Summary of Key Consultation Issues Raised relevant to the EIA Methodology (MS-LOT, 2022)

13. In addition to this, the Applicant has carried out several public consultation events. A summary of these events can be found in Table 6.2   Open ▸ .

Table 6.2: Public Consultation Events

6.4. Key Principles of the Proposed Development Assessment

6.4.1.    Overview

14. Within this Offshore EIA Report, the assessment of each topic (e.g. physical processes, marine mammals, infrastructure and other users, etc.) is presented in a separate topic specific chapter. Within each of the topic chapters, the following matters have been considered:

• identification of the study area for the topic specific assessments;
• description of topic specific legislation, policy and guidance;
• summary of consultation activity, including comments received as part of the Berwick Bank Wind Farm Scoping Opinion (MS-LOT, 2022);
• description of the environmental baseline conditions, including future baseline; and
• presentation of the assessment of likely significant effects, which includes:

–           identification of the maximum design scenario for each assessment of effects;

–           a description of the designed in measures adopted as part of the Proposed Development;

–           identification of likely impacts and assessment of the significance of their identified effects, taking into account any designed in measures adopted as part of the Proposed Development;

–           identification of any further mitigation measures required in respect of likely significant effects (in addition to those measures adopted as part of the Proposed Development), together with consideration of any residual effects;

–           identification of any future monitoring required;

–           assessment of any cumulative effects between the Proposed Development and other developments on a single receptor. These will include the Berwick Bank Wind Farm onshore, projects which have become operational since collection of baseline data, projects under construction, those with consent, projects for which an application for consent has been submitted but not yet determined, projects in scoping and where an Agreement for Lease (AfL) has been granted; and

–           assessment of any transboundary effects (i.e. effects on other European Economic Area (EEA) states).

15. Inter-related effects (i.e. inter-relationships between environmental topic areas) have been assessed in a separate standalone chapter (volume 2, chapter 20) which considers the impacts of the Proposed Development on each of the identified receptor groups and includes consideration of ecosystem assessment for relevant topics. In addition to this, each topic chapter of this Offshore EIA Report (volume 2, chapter 7 – 21) provides a summary of the inter-related effects for each specific topic.

16. In accordance with the EIA Regulations, the effects of climate change on future baseline conditions have been considered in the description of baseline conditions, as relevant, and therefore inherently considered in the assessment of LSEs on the receptors in the respective topic chapters (volume 2, chapters 7 - 21). The effects of the Project on the climate in form of a greenhouse gas (GHG) assessment, and the assessment of the Project’s resilience or vulnerability to climate change are included in the Climate Assessments Report (volume 3, appendix 21).
17. An assessment of In-Combination Climate Change Impacts (ICCI Assessment) has also been completed. This presents the effects of the Project in-combination with anticipated future climate change on environmental receptors (i.e. it assesses the extent to which anticipated future climate change exacerbates the effects of the Project on an identified environmental receptor) (IEMA, 2020). The ICCI Assessment is provided in the Climate Assessments Report (volume 3, appendix 21).
18. A number of key principles which have been applied to each topic chapter are detailed in sections 6.4.2 to 6.4.5 below.

6.4.2.    Evidence Based Approach

19. The Proposed Development is located in the outer Firth of Forth, for which there exists significant data and knowledge regarding the baseline environment. This data/knowledge has been acquired through the former Firth of Forth zonal studies, from the surveys and assessments undertaken for Seagreen Alpha/Bravo (referred to as Seagreen 1 and Seagreen 1A Projects when considered as part of the CEA for the Proposed Development) and from the surveys and assessment undertaken for the Inch Cape and Neart na Gaoithe (NnG) offshore wind farms, as well as site-specific surveys carried out as part of the Berwick Bank baseline studies. Where possible in this Offshore EIA Report, the Applicant has made use of these data to:

• characterise the baseline environment to inform the EIA where data are sufficient and appropriate to do so;
• identify data gaps;
• support scoping out of impacts where there is clear evidence of lack of a receptor-impact pathway; and
• where impacts are scoped in, to draw upon the pre-existing evidence base in addition to site specific and recent data where appropriate.
  20. Each topic chapter of this Offshore EIA Report (volume 2, chapters 7 - 21) seeks to provide a description of:
• the data that have been obtained, including the role of the current Firth of Forth zonal datasets, as well as publicly available desktop data sources, in defining the baseline environment for the Proposed Development;
• the role of the Firth of Forth zonal datasets, as well as publicly available desktop data sources (including an explanation as to whether this data is sufficient, appropriate and contemporaneous) in the Proposed Development assessments of effects; and
• if necessary, a description of additional data that have been collected to inform the Proposed Development assessment of effects.

6.4.3.    Maximum Design Scenario

21. The Project Design Envelope (PDE) approach (also known as the Rochdale Envelope approach) has been adopted for the assessment of the Proposed Development, in accordance with current best practice and the “Rochdale Envelope Principle[2]” (see volume 1, chapter 3). This requires the assessment of likely significant effects of the realistic ‘worst case’ parameters of the Proposed Development.
22. Volume 1, chapter 3 sets out the PDE parameters and identifies the range of potential project design values for relevant components of the Proposed Development. For each of the topic chapters (volume 2, chapters 7 - 21) within this Offshore EIA Report and for each of the effects assessed, the PDE considered will be the scenario which would give rise to the greatest potential effect (hereafter referred to as the maximum design scenario).
23. An example of the PDE approach would be where several types of wind turbine foundation are being considered. The assessment in this case would be based on the foundation known to have the greatest potential for impact on a given receptor. In this instance, the PDE for the foundation with the greatest seabed disturbance potential would be the foundation with the largest footprint (i.e. the maximum design scenario for benthic subtidal and intertidal ecology). It can be assumed that any project parameters equal to or less than those assessed will have environmental effects of the same level or less upon the receptors for the topic under consideration.
24. By identifying the maximum design scenario for any given impact, it can be concluded that the impact (and therefore the effect) will be no greater for any other design scenario than that assessed for the maximum design scenario. Employing the PDE approach allows the Applicant to retain necessary flexibility in design of the Proposed Development, within certain maximum scenarios, all of which are fully assessed in the Offshore EIA Report. Flexibility in design is required to ensure the best wind turbine technology for the site is procured and installed, which in the UK is a matter of years after EIA report production.

6.4.4.    Measures Envisaged to Avoid, Prevent, Reduce or, if Possible, Offset Likely Significant Adverse Effects

Overview

25. Where likely significant effects are identified, the EIA Regulations require ‘a description of the measures envisaged to avoid, prevent, reduce or, if possible, offset any identified significant adverse effects on the environment and, where appropriate, of any proposed monitoring arrangements’ to be included in the Offshore EIA Report (The Electricity Works (Environmental Impact Assessment) (Scotland) Regulations 2017: Schedule 4, Paragraph 7, The Marine Works (Environmental Impact Assessment) (Scotland) Regulations 2017: Schedule 4, Paragraph 8 and The Marine Works (Environmental Impact Assessment) (Scotland) Regulations 2007: Schedule 3, Paragraph 8).
26. The iterative approach to the assessment process for the Proposed Development involves a feedback loop, as illustrated in Figure 6.1   Open ▸ . A specific impact, and the significance of the resulting effect, is initially assessed, and if this is deemed to be a significant adverse effect in EIA terms, changes are made (where reasonably practicable) to relevant project parameters, design or specific mitigation measures are introduced to avoid, reduce or offset the magnitude of that impact. The assessment is then repeated, and the process continues, until the EIA practitioner is satisfied within the scope of the Project objectives that:

• the effect has been reduced to a level that is not significant in EIA terms; or
• having regard to other constraints, no further changes may be made to project design parameters or no practicable mitigation measures are available to reduce the magnitude of impact (and hence significance of effect). In such cases, an overall effect that is still significant in EIA terms may be presented in the Offshore EIA Report.

Figure 6.1: Proposed Iterative Approach to Mitigation Within the Proposed Development EIA

Designed in measures (Primary mitigation)[3]

27. IEMA (2016) describe Primary (inherent) mitigation as: “Modification to the location or design of the development made during the pre-application phase that are an inherent part of the project, and do not require additional action to be taken”.
28. Primary mitigation has been referred to as “designed in measures” within this Offshore EIA Report.
29. As described in paragraph 26, the iterative approach to the assessment process has been utilised to inform the design of the Proposed Development (through the identification of likely significant effects and development of designed in measures to address these). The incorporation of such measures within the design demonstrates commitment to implementing the identified measures. These measures have been referred to throughout the Offshore EIA Report as “designed in measures”.
30. By employing this approach, the significance of effect presented in the Offshore EIA Report is considered representative of the maximum residual effect that the Proposed Development will have, should the application for consent be approved and the Proposed Development be constructed and operated.

Secondary mitigation

31. IEMA (2016) describe Secondary (foreseeable) mitigation as: “Actions that will require further activity in order to achieve the anticipated outcome. These may be imposed as part of the planning consent, or through inclusion in the Environmental Statement”.
32. Secondary mitigation is considered as additional measures which are applied after the assessment process has been completed to prevent, reduce and offset LSEs which could not be avoided through designed in measures.

Tertiary mitigation

33. IEMA (2016) describe Tertiary (inexorable) mitigation as: “Actions that would occur with or without input from the EIA feeding into the design process. These include actions that will be undertaken to meet other existing legislative requirement, or actions that are considered to be standard practices used to manage commonly occurring environmental effects”.
34. Primary mitigation is inherent with the Project Description and tertiary mitigation is inexorable as described above, both types of mitigation are considered as designed in measures. Secondary mitigation proposed to reduce significance of impact are detailed within the topic chapters of the Offshore EIA Report and summarised in volume 3, appendix 6.3.

6.4.5.    Identification of Impacts and Significance of Effect

Impacts and effects

35. The Proposed Development has the potential to create a range of impacts and effects with regards to the physical, biological and human environment, for both coastal and marine receptors.
36. For the purposes of the Offshore EIA Report, the term ‘impact’ is defined as a change that is caused by an action. For example, the laying of an inter-array cable (action) is likely to result in seabed disturbance (impact). Impacts can be defined as direct, indirect, temporary, irreversible, secondary, cumulative and inter-related. They can also be either positive or negative, although the relationship between them is not always straightforward and relies on available evidence and professional judgement.

Table 6.3:  Definition of Impact Terms Relevant to the Offshore EIA Report

37. The term ‘effect’ is defined as the consequence of an impact. For example, following the inter-array cable laying example described in paragraph 36, the laying of an inter-array cable (action) results in seabed disturbance (impact), with the potential to disturb benthic habitats and species (effect).
38. The significance of effects is determined by consideration of the magnitude of impact alongside the sensitivity of each receptor/receptor group in accordance with the defined significance criteria.

Scope of the assessment

39. The scope of this Offshore EIA Report complies with the requirements set out by the EIA Regulations as discussed in volume 1, chapter 2.
40. In October 2021, the Applicant submitted the Berwick Bank Wind Farm Offshore Scoping Report (SSER, 2021a) to MS-LOT to support a request for a formal Scoping Opinion in relation to the Proposed Development from Scottish Ministers. The Scoping Opinion (Berwick Bank Wind Farm Scoping Opinion (MS-LOT, 2022)); was received in February 2022.

41. Based on the Berwick Bank Wind Farm Scoping Opinion (MS-LOT, 2022), the nature, size and location of the Proposed Development and other consultation responses provided throughout the EIA process (including consultation with Statutory Nature Conservation Bodies (SNCBs) and the Road Map process), the Offshore EIA Report focuses on the following topic areas (impacts of infrastructure and activities seaward of MHWS on receptors):

• Physical Processes (volume 2, chapter 7);
• Benthic Subtidal and Intertidal Ecology (volume 2, chapter 8);
• Fish and Shellfish Ecology (volume 2, chapter 9);
• Marine Mammals (volume 2, chapter 10);
• Offshore and Intertidal Ornithology (volume 2, chapter 11);
• Commercial Fisheries (volume 2, chapter 12);
• Shipping and Navigation (volume 2, chapter 13);
• Aviation, Military and Communications (volume 2, chapter 14);
• Seascape, Landscape, Visual Resources (volume 2, chapter 15);
• Cultural Heritage (volume 2, chapter 16)
• Infrastructure and Other Users (volume 2, chapter 17);
• Offshore Socio-economics and Tourism (volume 2, chapter 18);
• Water Quality (volume 2, chapter 19)
• Inter-Related Effects (volume 2, chapter 20);
• Major Accidents and Disasters (volume 2, chapter 21) and
• Climate (volume 3, appendix 21).
  42. Table 6.4   Open ▸ outlines the requirements of the EIA Regulations and where these requirements have been considered within this Offshore EIA Report.

Table 6.4: EIA Regulations Requirements and Where in this Offshore EIA Report these are Addressed

Determining magnitude of impacts

43. The magnitude of an impact is the consideration of the spatial extent, duration, frequency and reversibility of an impact from the construction, operation and maintenance or decommissioning of the Proposed Development. The magnitude is assigned to each of the impacts assessed within the Offshore EIA Report.

Table 6.5: Definition of Terms Relevant to Defining the Magnitude of an Impact (Highways Agency et al., (2008) and Chartered Institute of Ecology and Environmental Management (CIEEM) (2018))

44. The magnitude of the impact is defined within each topic chapter according to the following scale:

• negligible;
• low;
• medium; and
• high.
  45. Framework definitions for each of these categories is set out in Table 6.6   Open ▸ , which describes both positive and negative magnitudes of change (adapted from Highways Agency et al. (2020)). Each of the topic chapters contains topic-specific definitions for each of these categories which are based upon topic-relevant external policy, guidance, standards and other material, including specialist knowledge.

Table 6.6: Definition of Terms Relating to the Magnitude of an Impact (Highways Agency et al., 2020)

Determining sensitivity of receptors

46. Receptors can be defined as the physical or biological resource or human user group that could be affected by the potential Proposed Development impacts. These receptors are identified through available data and baseline studies compiled in the development of the Offshore EIA Report.
47. In defining the sensitivity for each receptor/receptor group, the vulnerability, recoverability and value/importance of that receptor will be taken into consideration. These terms are defined in Table 6.7   Open ▸ and are used on a basis appropriate to each topic chapter. In instances where these considerations are not included in the assessment, the reason for this is explained within the relevant topic chapter.

Table 6.7: Definition of Terms Relevant to Defining the Sensitivity of a Receptor

48. Sensitivity is defined within each topic chapter according to the following scale:

• negligible;
• low;
• medium;
• high; and
• very high.
  49. Framework definitions for each of these categories is set out in Table 6.8   Open ▸ , based on the Highways Agency et al. (2020). Each of the topic chapters contains topic-specific definitions for each of these categories which are based upon topic-relevant external policy, guidance, standards and other material, or specialist knowledge.

Table 6.8: Definition of Terms Relating to the Sensitivity of the Receptor (based on Highways Agency et al., 2020)

50. The following topic chapters have followed specific EIA methodology which deviates from the one described in this chapter. These include:

• Commercial Fisheries;
• Seascape, Landscape and Visual;
• Socio-economics and Tourism; and
• Shipping and Navigation.
  51. The topic specific EIA methodology is included as part of the mentioned chapters.

Determining significance of effect

52. The overall significance of an effect is determined through the correlation of the magnitude of impact alongside the sensitivity of the receptor. To ensure consistency in defining the significance of an effect, a matrix approach has been adopted, as presented in Table 6.9   Open ▸ . In cases where a range is suggested for the significance of effect, there remains the possibility that this may span the significance threshold (i.e. the range is given as minor to moderate). In such cases the final significance is based upon the expert's professional judgement as to which outcome delineates the most likely effect, with an explanation as to why this is the case.
53. The matrix approach is consistent with the general approach described in the Design Manual for Roads and Bridges (DMRB) (Highways England et al., 2020) and Environmental Impact Assessment for Offshore Renewable Energy Projects – Guide (BSI, 2015). A number of modifications have however been made in the interest of proportionality, including:

• an impact magnitude of ‘no change’ will always lead to a non-significant effect as per the matrix approach included in Table 6.9   Open ▸ ;
• an impact of negligible magnitude will always lead to a non-significant effect as per the matrix approach included in Table 6.9   Open ▸ ; and
• receptors of negligible importance, value or sensitivity will not be considered further because it will always lead to a non-significant effect as per the matrix approach included in Table 6.9   Open ▸ .
  54. Significant effects to be assessed as part of the Offshore EIA Report have been agreed with SNCBs and stakeholders as part of the scoping exercise and Road Map process.

Table 6.9: Matrix Used for the Assessment of the Significance of the Effect

55. For the purposes of this assessment:

• a level of significance of effect of moderate or more will be considered a ‘significant’ effect in terms of the EIA Regulations; and
• a level of significance of effect of minor or less will be considered ‘not significant’ in terms of the EIA Regulations.
  56. Effects of moderate significance or above are therefore considered important in the decision-making process, whilst effects of minor significance or less warrant little, if any, weight in the decision-making process. The definition of each of the significance levels are presented in Table 6.9   Open ▸ .
  57. Significant effects (in terms of the EIA Regulations) identified during the assessment will be subject to secondary mitigation to reduce or offset the effect (paragraphs 58 and 59). Where resulting residual effects (taking into account mitigation) are still significant these will require further consideration as part of the decision making process to determine whether the effects are acceptable (paragraph 60).

Table 6.9: Definition of Significance Levels for the Proposed Development (based on Highways Agency et al., 2020)

Secondary mitigation measures

58. If the effect of an impact presents a major significant adverse outcome, changes are typically made to the Proposed Development design (primary mitigation) to reduce or offset the magnitude of impact or secondary mitigation is proposed to reduce magnitude of impact. If the effect of an impact presents a moderately significant adverse outcome, mitigation such as engineering controls or construction methods (secondary mitigation) are employed to reduce or offset the magnitude of the impact as outlined in section 6.4.4 paragraph 26.
59. Volume 3, appendix 6.3 provides a summary of the mitigation commitments, including the designed in mitigation (primary and tertiary) and secondary mitigation measures detailed within the topic chapters of the Offshore EIA Report. The means of implementation is also specified for each of the mitigation commitments.