Offshore wind energy - draft sectoral marine plan: habitat regulations appraisal

4 Assessment Information (Stage 8)

4.1 Introduction

4.1.1 Acknowledging case-law judgements that took place in 2018, it was recommended that Stages 6 and 7 of the plan-level HRA process were not formally considered (see Section 1.3). Instead the process (as shown in Figure 1)  moves from Stage 5 directly to Stage 8 (assessment), followed by consideration of mitigation (Stage 9).  Stage 10 encompasses the provision of the draft HRA record (this document) (see Section 1.3).

4.1.2 The following sections of the report (Sections 4 to 10) encompass the assessment of the screened in European/Ramsar sites and the relevant interest features (see Table C1) (Stage 8). This includes consideration of in-combination effects (Section 10) before discussing mitigation and the application of suitable measures at a plan-level (Section 11).

4.1.3 The assessment methodology is detailed within the pre-screening report (Section 4.9, Appendix A). A summary of the key steps is outlined below:

• Step 1: Impact pathways review - Identification of the impact pathways that are relevant for offshore wind development;
• Step 2: Identify activities to which features are sensitive - A review of the activities involved in offshore wind development, and the environmental changes arising, which could have an impact on European/Ramsar sites or interest features via the identified impact pathways;
• Step 3: Activity-based screening of European/Ramsar Sites – Identification (screening) of those European/Ramsar sites and their relevant interest features for which there is a LSE, or for which a LSE cannot be excluded, from the activities and impact pathways;
• Step 4: Detailed pathway-feature sensitivity review - A review of the sensitivities of the relevant interest features to the identified impact pathways and activities; and
• Step 5: Assessment of the potential effects on European/Ramsar sites - Assessment of impacts via each of the activities associated with offshore wind development both alone and in-combination with other extant plans or projects. This is followed by the identification of available plan-level mitigation measures which ensure that the Sectoral Offshore Wind Plan activities have no AEOI.

4.1.4 Steps 1-3 were carried out during the pre-screening (steps 1 and 2) (Appendix A) and screening (step 3) stages (see Sections 2 and 3; and Appendices C and D). The relevant generic impact pathways are as identified in the pre-screening (see Table A1 in Appendix A), as are the individual activities to which features are sensitive (see Table A2 in Appendix A).  These tables have been referred to during subsequent steps; however, to facilitate cross-referral the generic impact pathways identified are provided below (Table 2).

Table 2. Generic impact pathways associated with the Draft Plan

4.1.5 Step 4 considers those relevant project-level activities associated with the Draft Plan that have been screened into the assessment (see Section 4.13, Appendix A). The results are presented in a series of ‘pathway-sensitivity’ tables, within the main body of this document, for each key interest feature group. During this process, acknowledgement is given to the latest scientific evidence to understand the likely sensitivity of a feature to a specific impact pathway.

4.1.6 The ‘pathway-sensitivity’ tables are structured according to the standard Natura 2000 sensitivity categories (see Section 3.2.3, Appendix A):

• Physical Loss/Gain of habitats from removal or smothering;
• Physical Damage of habitats and species from siltation, erosion or physical injury/death;
• Non-Physical (Indirect) Disturbance from noise or visual presence and reduced availability or exclusion/displacement of species, including prey;
• Toxic Contamination from the introduction of synthetic compounds, introduction of non-synthetic contaminants;
• Non-Toxic Contamination from nutrient enrichment, organic enrichment, changes in suspended sediment and turbidity, changes in salinity or changes to the thermal regime; and
• Biological Disturbance from introduction of microbial pathogens, the introduction of invasive non-native species and translocation, or from selective extraction of selected species.

4.1.7 The tables indicate which project phases the impact pathways are relevant to (i.e. survey, construction, operation or decommissioning) and the sensitivity levels (high, medium or low) associated with each of these phases. The impact pathway reference numbers are included within each pathway-sensitivity table, these numbers relating to the generic impact pathways identified in Step 1 (see Table 2).

4.1.8 The determination of the sensitivity of a feature to a given impact pathway has considered both the function of the sensitivity to the pressure and also the likely level of exposure. In the case of mobile features an individual may have a high sensitivity to a pressure but exposure to the pressure may be minimal, especially at the population level.

4.1.9 Impact pathways arising as a result of the development footprint are considered to occur in the operational rather than construction phase, reflecting the longer-term nature of the impact.

4.1.10 Step 5 assessed the impacts that could occur via each of the identified pathways against the European/Ramsar site’s conservation objectives. However, given the large number of sites screened into the assessment, a series of generic conservation objectives were applied across all sites (see Section 4.14.2, Appendix A).

4.1.11 Based on these generic conservation objectives, the potential effects on the European/Ramsar sites via each of the relevant impact pathways were reviewed. An initial view was then taken about the effect on site integrity of the Sectoral Offshore Wind Plan both alone and in-combination (Section 10) with other extant plans or projects.

4.1.12 It has already been agreed through discussion with the PSG (Section 2.2.3, Appendix B) that because of the uncertainties associated with the Draft Plan (including the scale and location of future developments within the DPOs and the nature of the future technologies that will be used), it will not be possible to definitively conclude that there will be no AEOI from the Plan.  Therefore, there will be a need for appropriate and meaningful mitigation measures to accompany the Draft Plan.

4.1.13 Accordingly, plan-level mitigation measures were identified to avoid an AEOI (Section 11), in fulfilment of Stage 9 of the HRA process (Figure 1). The Draft Plan was then re-assessed following the application of these mitigation measures and the conclusions provided (Section 12).

4.2 Key Issues

4.2.1 For plan-level assessments, it is recognised that there is often limited information on the precise location and scale of development or about the relevant construction methods and associated activities.  This is typically the case at a plan-level and while the 17 DPOs have been agreed and their locations are indicated (e.g. see Figure 3), no project-level details are currently available for these DPOs.  The uncertainty about project level details has duly been recognised throughout the screening and assessment stages.

4.2.2 The assessment has, therefore, taken account of the likely range of development options and activities based on previous wind energy projects that have been carried out or are proposed. It also acknowledges the potential for floating turbine structures to allow exploitation of deep-water sites.

4.2.3 The Sectoral Marine Plan for Offshore Wind has a relatively broad spatial scope and a long-term temporal component which can each influence the range of potential impacts.  The temporal aspects of the Draft Plan’s implementation, and the scale of the impacts associated, will also be influenced by technological advances that take place over time with respect to wind energy developments.  These will influence the scale of potential impacts as well as the distances offshore that developments can be undertaken while remaining commercially viable. It will also influence the needs for future upgrading of wind generating technologies in established areas.  In this context, therefore, it has been essential for these assessments that no specific assumptions about project-level activities (e.g. device type or generation capacity) are made in the absence of available information and that the potential impacts that are identified encompass the full envelope of potential change (through the application of a precautionary approach).

4.2.4 This potential envelope of change has therefore been determined to identify the potential effects on features. On this basis, screening matrices and maps for the individual DPOs (see Appendices D and E) have identified where features within individual sites are at risk of LSE (or where the risk of LSE cannot be excluded). The detailed assessment presented in this report has built on this screening process by considering the particular environmental pressures/changes that give rise to these risks and then providing a generic assessment of the impact having regard to the typical conservation objectives (see Section 4.14.2, Appendix A).

4.2.5 Based on the approaches adopted for previous plan-level HRA work, the results of this phased assessment work have been presented in a series of tables/matrices throughout the following sections (Section 5 to 9).