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Strategic Environmental Assessment (SEA) of Draft Plan for Offshore Wind Energy in Scottish Territorial Waters: Volume 1: Environmental Report


2 SEA Methodology

2.1 SEA Approach

A summary of the SEA process, which is being applied to the development and assessment of the Plan, is shown in Figure 2-1.

Figure 2-1: Summary of the SEA Process

Figure 2-1: Summary of the SEA Process

2.2 Screening and Scoping

The need for SEA of the Plan was established by the Scottish Government and confirmed in a Screening Determination. This confirmed that the nature of the Plan, combined with its scale and the sensitivity of the marine environment, has the potential for significant environmental effects. An SEA has therefore been undertaken in accordance with Section 5(4) of the Environmental Assessment (Scotland) Act 2005.

A combined screening and scoping report was prepared by the Scottish Government in June 2009 to:

  • define the context and scope of the SEA;
  • set out the approach to the assessment;
  • provide details of the next steps to be undertaken; and
  • provide the Scottish Government's screening opinion.

The scoping process (i.e. to identify the main environmental issues requiring consideration during the development of the Plan) identified key sources of data, provided an overview of potential effects and outlined the range of methods that would be appropriate for this SEA. Scoping also identified that significant effects on local or regional air quality are unlikely to occur and this topic was therefore scoped out of the SEA.

The combined Screening and Scoping Report was submitted for formal consultation with the SEA Consultation Authorities and additional key consultees. Comments were received from:

  • SNH;
  • Historic Scotland;
  • SEPA;
  • RSPB;
  • Scottish Renewables;
  • Scottish Power Renewables;
  • SeaEnergy Renewables Ltd;
  • EDP Renováveis; and
  • RWE npower renewables.

The comments received broadly welcomed the SEA and focused primarily on issues relating to avoiding the sterilisation of marine areas by application of the precautionary principle, scheduling, applicability of certain data sources and the level of detail required for components of the SEA.

2.3 Identification of Generic Effects

Building on the findings of the Screening and Scoping Report and the DECC (2009) SEA, as a first step in the process all potential generic effects associated with development of offshore wind energy were identified. Those effects that are most appropriately addressed or managed at a site specific or regional level, either through the EIA process or as a part of ongoing project management, were filtered out of the strategic level assessment. The remaining list identifies those effects that have been addressed at a strategic level within this SEA (see Chapter 4).

2.4 Baseline Data Collection

A review of all the available information was undertaken to collate baseline information to define the environmental conditions (both current and future) ( Chapter 5) against which the effects of the proposed Plan could be assessed. Data held on The Crown Estate's Marine Resource System ( MaRS) and previous SEA studies provided part of the baseline data.

The available baseline information was reviewed in the light of the strategic potential effects to again separate out those sensitivities that can more appropriately be addressed at a project level and those that need to be considered at the strategic level.

The technical requirements for the deployment of offshore wind energy development were reviewed to identify if any of them limited where wind farms could be constructed. The Plan discusses how these technical considerations were considered.

2.5 Establishing SEA Objectives

A series of SEA objectives were identified to develop and appraise alternative options for offshore wind development (see Chapter 7). These were developed taking into account environmental regulations and our current understanding of the key environmental issues within the STW.

Each objective was divided into a series of more specific sub-objectives. Under these objectives and sub-objectives, a series of indicators were identified to test compliance and measure the performance of each potential option (subject site or area) with the objectives.

2.6 Options Considered

Options for the short, medium and long term are identified in the draft Plan and are described in Chapter 7.

2.7 Assessment Methodology

The development of the options and the assessment was an interactive process that included extensive consultation with consultation authorities, representatives of the renewable energy industry and wider stakeholders as described in section 2.11 below.

The SEA took a phased approach that considered the ten short term options as a priority and then examined other areas with potential for development (Figure 2-2). Figure 2-2 also shows the outline programme for the study.

Figure 2-2: Methodology Flowchart

Figure 2-2: Methodology Flowchart

2.7.1 Assessment of the Short Term Plan

For the short term, the ten STW options were reviewed against the baseline data. Each of the options or groups of sites were then tested against the SEA objectives using the available baseline information and known strategic issues. The majority of the baseline information can be mapped and the test usually could be answered by a simple overlay of the options against the potential sensitivities, considering magnitude and likelihood.

In all cases the data's quality was assessed and the Precautionary Principle 3 was applied. A commentary of the compliance of each site and achievement of objectives was then prepared to build up a picture of suitability for development. This commentary also identified issues requiring further investigation or management at the EIA/project level.

2.7.2 Assessment of the Medium and Long Term Options

The SEA objectives were applied to the medium term options as with the short term options and a commentary was produced that identified at a high level those sensitivities that are likely to be of most importance or will need further consideration and assessment. This provides a medium term view for development.

The areas with potential for development in the long term are identified as those outside of the medium term options and exclusion areas. It was not considered feasible to assess these areas at this stage as they are likely to be developed after 2030, when significant changes are likely to have occurred to the baseline and planning and legislative context. By that stage there may be significant technical changes, such as grid connection infrastructure. Hence, long term options are not assessed in this SEA, but will need to be assessed once such plans have been developed in the future.

2.7.3 Cumulative Assessment

Cumulative effects may be defined as:

  • Cumulative - the combination of effects caused by the same or similar developments in an area, e.g. all of the effects of a single wind farm or group of wind farms; and
  • In-combination - the effects of wind energy development with other marine users/plans in the area.

The cumulative effects of the options were tested for compliance against the objectives. In all cases the potential effects may be synergistic, i.e. the different effects may evolve as a result of the combination of the individual effects.

In exactly the same manner in which the compliance of individual options with the SEA objectives was tested, the cumulative effects were assessed. However, this required some knowledge of the scheduling of the developments. As that information is not specified within the draft Plan as a result of its strategic perspective, the commentary assumes approximately concurrent development of options over the next few years. The assumption of concurrent development is a worst case scenario from an environmental perspective, and was used in order to identify the likelihood of the most significant possible environmental effects. Recommendations for further assessment are also made.

The options that might reasonably be expected to have more regional cumulative effects because of their proximity to each other, plus other major activities/plans that might fall within a similar footprint (e.g. adjacent Round 3 sites or oil and gas activity), were considered. It is not within the scope of this SEA to provide a detailed assessment of those other industries; rather, it is intended to highlight likely interactions that may warrant greater attention. A qualitative assessment of the impact on each SEA receptor was made, which took this into account as far as possible.

2.8 Reporting

The results of the SEA process are documented in this ER, which identifies, describes and evaluates the likely significant environmental effects of the draft Plan, as well as the alternative options. To avoid repetition in reporting, only those key sensitivities that need to be considered at a strategic level are summarised in this ER.

Where appropriate, mitigation was identified to minimise any adverse effects of implementing the draft Plan.

The draft Plan may be modified in light of comments received from consultees before it is formally adopted. A Post-Adoption SEA Statement will be produced to show how comments have been taken into account in to the process of finalising the Plan.

2.9 Implementation and Monitoring

The key principles of implementation and monitoring are to ensure that the mitigation measures are implemented and are both practical and effective. Monitoring is intended to demonstrate the accuracy of impact prediction and success of any mitigation. This will inform future iterations of the Plan and the SEAER.

The SEA will be periodically reviewed by Marine Scotland (currently proposed to take place after two years) and SEA Maintenance will be carried out as and when necessary.

2.10 Regional Management of Issues

The Crown Estate's exclusivity agreements and licensing provides a mechanism to coordinate monitoring and management of potential sensitivities over a number of options or a wider area. This enables the management of some cumulative effects. Where appropriate, recommendations are made for a co-ordinated approach to assessment, monitoring and management.

2.11 Approach to Consultation

2.11.1 Introduction

Consultation has been central to the development of the SEA in order to arrive at a Plan that is acceptable to as many parties as possible and to engage those parties in the process. Effective external stakeholder and public engagement have been essential for data collection, identification of key issues, definition of SEA objectives and the selection of the preferred options in the draft Plan.

The main purpose of communicating with stakeholders throughout the development of the SEA is to contribute to the success of the Plan and improve decision-making by:

  • raising early awareness of environmental management issues relating to offshore wind development;
  • allowing stakeholder input into the environmental decision-making in the context of the Plan;
  • informing the development of the SEA by identifying and, where appropriate, addressing the concerns of external parties;
  • allowing representations made by stakeholders to be taken into account throughout the SEA process, particularly in the selection and environmental assessment of options; and
  • meeting regulatory requirements for consultation under the the Environmental Assessment (Scotland) Act 2005.

The main activities have comprised:

  • invitations to provide data and comments;
  • circulation of draft documents for comment; and
  • stakeholder meetings and workshops with representatives of key organisations to allow them to understand the process being undertaken, inform the process and raise any concerns.

Where appropriate, the proposed process was reviewed and adapted accordingly. For example, it was originally proposed that a 60m water depth was utilised to differentiate between medium term and long term options. However discussions with developers identified that floating platform technology is further advanced than originally considered and as such, deployment in deep water is foreseeable in the medium term. Similarly stakeholders raised issues in relation to navigation and fishing and additional studies were undertaken to address these points.

Stakeholder dialogue ensured that all appropriate issues were taken account of within the assessment.

2.11.2 Stakeholders

A Stakeholder Engagement Plan was developed to support the SEA and HRA of the Plan. The following stakeholder groups were identified to ensure that an appropriate range of stakeholders were engaged throughout the project:

  • Scottish Government;
  • Consultation Authorities and Agencies;
  • Non-Governmental Organisations;
  • land owners;
  • marine users;
  • wind farm developers; and
  • the wind industry supply chain.

2.11.3 Stages of Consultation

A summary of the key stages of stakeholder consultation is presented in Table 2-1.

Table 2-1: Summary of key stages of stakeholder consultation


Purpose of stakeholder involvement for the SEA


Method of involvement

Key issues raised

Screening and Scoping

Determine the requirement for and scope of a statutory SEA

SEA Consultation Authorities 4

Representatives from key consultee groups 5

Circulation of combined SEA Screening and Scoping Report and formally submitted via the Scottish Government's SEA Gateway.

Confirmed requirement for SEA to be carried out (screening). Provided advice on data sources and confirmed that they were content with the key principles that were proposed to form the basis of the assessment methodology. Stakeholders also raised a number of key issues and anticipated likely effects of the Plan, to be taken into account within the assessment.

SEA Approach, Baseline and Establishing SEA Objectives (post scoping)

Inform interested parties that a Plan is being developed

Agree the approach to developing the Plan and the SEA

Request environmental baseline information

Ensure all relevant environmental issues/features are identified

Ensure that our list of consultees is correct

SEA Consultation Authorities

Workshop on 5 January 2010 and follow-up email and telephone correspondence

Stakeholders required an approach based on SEA testing against objectives. It was felt that many of the preliminary constraints identified could be managed at a site specific level. Consequently the methodology was revised to place greater emphasis on compliance with SEA objectives and less emphasis on potential technical issues which are likely to be overcome with technological advancement of the industry.

Offshore Wind Industry Group ( OWIG) 6.

Presentation on 12 January 2010 and subsequent discussion

Industry emphasised the importance of objective-based assessment and advised that the Plan development focussed on environmental rather than technical issues.

Wider stakeholders including developers, shipping industry, fishing industry

Stakeholder workshops on 3 and 5 February 2010

The two main issues arising were associated with navigation and inshore fisheries. Marine Scotland undertook to source additional information on inshore fisheries for inclusion in the Plan.

Option Identification and Assessment

Check that the environmental issues are adequately identified

Check that the revised SEA objectives are acceptable

Request additional environmental baseline approach

Discuss approach to option identification and assessment

Engage members of all stakeholder groups

Chamber of Shipping, Maritime & Coastguard Agency, Port Operators, RYA

Meeting on 19 February 2010

Consultees agreed to provide additional navigation route information to be taken account of within the assessment process.

Statutory Public and Stakeholder SEA Consultation on the ER

Provide opportunity for comment on the draft Plan and SEA

Scottish Government

The public and all stakeholders

Statutory advertisement of the ER

ER and draft Plan made available to consultees on the Scottish Government website

Stakeholder workshops to discuss the content of the ER

Broader awareness raising to encourage public participation in the SEA process to be undertaken.

Consultation views to be received.

Finalise Plan

Review output from public consultation & the responses

Produce a Post-Adoption Statement

SEA Consultation Authorities, Key Stakeholders, the public and other interested parties

Consult further on issues arising from Finalisation of the Plan if required.

Consultation views to be received.

Disseminate the Finalised Plan

Inform stakeholders of the Finalised Plan

SEA Consultation Authorities, Key Stakeholders, the public and other interested parties

Finalised Plan published and implemented. Post Adoption SEA Statement made available online and advertised as required.

Consultation views to be received.

2.12 Assumptions and Limitations of this SEA

The following key assumptions were made:

  • existing sources of information have been assumed to be correct;
  • blade tip heights of 150m (after Scott et. al 2005) were assumed for visual assessment. Tip heights are expected to increase with future developments in technology, but this has not been included in the assessment at this stage, as it uses a currently accepted methodology. The seascape/landscape and visual amenity sub-objectives therefore has the potential to underestimate future effects, but this has been acknowledged within the final evaluation of the findings;
  • no consideration is given to onshore grid connections and this SEA considers development to the shoreline, including intertidal, subtidal and immediate coastal areas. Offshore cable routes are not defined and are assumed to be broadly as a straight-line connection between development and shore;
  • legislation in Scotland may be subject to change.

Where data gaps or lack of understanding exist then 'uncertainty' is introduced into the Plan and into the prediction of environmental effects. A number of data gaps, uncertainties and technical deficiencies limit the scope and content of the assessment. These include:

  • a lack of quantitative baseline indicator data to cover all SEA topics/issues, in particular, those relating to marine wildlife, geology, sediments and coastal processes and human health and safety;
  • gaps in our current understanding of the marine environment. For example, the distribution and seasonality of some marine mammals, birds and fish are not uniformly or fully understood around the entire coast. Therefore, the description of the existing environment should be recognised as indicative and an outline of priorities for further assessments of developments at a regional or project level has been provided; and
  • uncertainty regarding the presence of submerged marine structures and buried assets including underwater archaeological features. There is therefore some risk that project level assessment may identify new or different constraints that may affect the siting of offshore wind farms.

The identification of potential impacts that will need to be addressed at both project and strategic level has ensured that these uncertainties have been included in the assessment process. The issues are noted and additional studies at regional and site level have been prioritised to address the most significant and pertinent issues and current uncertainties.