5.5. Assessment of Adverse Effects in-Combination with other Plans and Projects

  1. As detailed in section 4.6, certain impacts were excluded from further consideration if their assessment at the project level indicated negligible effects, deeming them inconsequential to any meaningful contribution to an existing cumulative impact. Following the alone assessment, the following effect pathways were excluded from the in-combination assessment:
  1. Sites and features were included within the in-combination assessment if any of the following criteria were met during the alone assessment:
  • the Array alone impact from displacement and/or collision at the Array is greater than or equal to one individual per year (following the most precautionary approach to assessment); and/or
  • the Array alone impact at the Array results in an increase in mortality rate of greater than or equal to 0.02 percentage points; and/or
  • an Appropriate Assessment for one or more of the other considered plans has identified a potential AEOI to the feature.
  1. If none of the above criteria are met, it was concluded, beyond reasonable scientific doubt, that the Array, in combination with other plans or projects, does not pose any potential for an AEOI.
  2. Based on the evaluation of the Array alone (section 5.4) and the above criteria, it was concluded that the only impact pathways for which there is the potential for an in-combination effect are disturbance and displacement, and collision risk. A potential in-combination effect has only been identified during the operation and maintenance phase.
  3. The sites, features and impacts that require an in-combination assessment are presented in Table 5.61   Open ▸ .

 

Table 5.61:
Assessment of Features of SPA or Ramsar sites Requiring In-Combination Assessment

Table 5.61: Assessment of Features of SPA or Ramsar sites Requiring In-Combination Assessment

 

  1. The sites that do not meet any of the criteria set out in paragraph 351 are:
  • Copinsay SPA;
  • Fair Isle SPA;
  • North Rona and Sula Sgeir SPA;
  • Outer Firth of Forth and St Andrew’s Bay Complex SPA;
  • Sule Skerry and Sule Stack SPA;
  • Cameron Reservoir SPA and Ramsar site;
  • Din Moss - Hoselaw Loch SPA and Ramsar site;
  • Fala Flow SPA and Ramsar site;
  • Firth of Forth SPA and Ramsar site;
  • Firth of Tay and Eden Estuary SPA and Ramsar site;
  • Gladhouse Reservoir SPA and Ramsar site;
  • Greenlaw Moor SPA and Ramsar site;
  • Holburn Lake and Moss SPA and Ramsar site;
  • Lindisfarne SPA and Ramsar site;
  • Loch of Kinnordy SPA and Ramsar site;
  • Loch Leven SPA and Ramsar site;
  • Montrose Basin SPA and Ramsar site;
  • Northumbria Coast SPA and Ramsar site;
  • Slamannan Plateau SPA;
  • South Tayside Goose Roosts SPA and Ramsar site;
  • Westwater SPA and Ramsar site; and
  • Ythan Estuary, Sands of Forvie and Meikle Loch SPA, Ythan Estuary and Meikle Loch Ramsar site.

 

  1. For all these sites, as set out above, it has been demonstrated that that Array will not make a meaningful contribution to any cumulative impact, and therefore it is concluded beyond reasonable scientific doubt that the Array will not cause an AEOI to any of those sites.

5.5.1. In-combination data sources

  1. The in-combination assessment for ornithology requires the mortality from each other relevant project apportioned to the SPA or Ramsar site being assessed. Primarily, this has been drawn from the recent Berwick Bank Offshore Wind Farm RIAA (SSE Renewables, 2022) as the most comprehensive recent compilation. It should be noted that Berwick Bank Offshore Wind Farm do not provide in-combination values for individual projects but totalled for the UK North Sea region. Where values were not available from Berwick Bank Offshore Wind Farm, other data sources were used as necessary.
  2. In addition, project-alone values for more recent applications have been added to the Berwick Bank Offshore Wind Farm totals, specifically Green Volt Offshore Wind Farm (Green Volt Offshore Wind Farm, 2023), West of Orkney Wind Farm (Offshore Wind Power Limited, 2023), Pentland Floating Offshore Wind (Xodus Group Ltd, 2022), Five Estuaries Offshore Windfarm (Five Estuaries Wind Farm Ltd, 2023), Outer Dowsing Offshore Wind (Outer Dowsing Offshore Wind, 2023) and Sheringham Shoal and Dudgeon Offshore Wind Farm Extension Projects (hereafter SEP & DEP) (Equinor, 2022, 2023). As quantitative information for these projects was not available at the time Berwick Bank Offshore Wind Farm was compiling its assessment, values for these projects are not included in the UK North Sea totals presented by Berwick Bank Offshore Wind Farm.
  3. The number of mortalities for other projects is dependent on the approach used for assessment. There is scope for this to vary, for example using different displacement rate/mortality rates to assess distributional responses, or different avoidance rates to assess collision mortality. Typically, more than one approach is presented to give a range of plausible impact mortalities. In particular, Berwick Bank Offshore Wind Farm followed a “dual approach” to assessment, presenting both a “Scoping Approach” (following advice from SNCBs, as presented in the NatureScot guidance notes) and a “Developer Approach” (the preferred approach of that project’s developer). Where the Scoping Approach is used to assess a range of impacts, the lower and upper end of that range are distinguished as “Scoping A” and “Scoping B” respectively. For more details on the approaches to assessment used in previous assessments, refer to the source document referenced (SSE Renewables, 2022).
  4. This in-combination assessment presents the full range of impact mortalities, as presented in the source material, and from that range considers the lowest value and the highest value presented for each other project (identified here as the approach applied by each project), in order to create a “low” approach total (which is typically either the project applicant’s preferred approach or the lower end of the SNCB approach) and a ”high” approach total (typically the more precautionary end of the SNCB approach).
  5. Where quantitative assessment is not available in the source data for a project for a feature/site, this is shown as “N/A” in the tables in each assessment. If no quantitative information is available, this is indicative that the source assessment concluded, beyond reasonable scientific doubt, that the project had either no connectivity or a negligible impact on the feature/site.
  6. In line with NatureScot’s comments on the Offshore HRA Screening Report (Ossian OWFL, 2023) ( Table 2.1   Open ▸ ), the assessment has been carried out both including impacts from Berwick Bank Offshore Wind Farm and excluding those impacts. Where the in-combination totals are sources from the Berwick Bank Offshore Wind Farm RIAA (SSE Renewables, 2022), Berwick Bank Offshore Wind Farm’s own impact is included in the UK North Sea regional totals (with the contribution from each project drawing on public domain information). Therefore, the scenario excluding impacts from Berwick Bank Offshore Wind Farm is calculated by simply subtracting the Berwick Bank Offshore Wind Farm alone impacts from the UK North Sea regional total (with results presented as low and high, based in the Berwick Bank Offshore Wind Farm Developer and Scoping B approaches).

                        Addendum: Green Volt Decision

  1. It is noted that towards the finalisation of this RIAA, a decision on the Green Volt Offshore Wind Farm application was published, with consent granted by the Scottish Ministers (Scottish Government, 2024). Before reaching this decision, the Scottish Ministers carried out an Appropriate Assessment (Appendix B of Scottish Government, 2024) and concluded that an AEOI in-combination is either expected or cannot be ruled out for the following SPA and feature combinations that are relevant for the Array assessment:
  • Kittiwake at Buchan Ness to Collieston Coast SPA;
  • Kittiwake, guillemot and razorbill at East Caithness Cliffs SPA;
  • Gannet and puffin at Forth Islands SPA;
  • Kittiwake at Fowlsheugh SPA; and
  • Kittiwake at Troup, Pennan and Lion’s Head SPA.
  1. Green Volt Offshore Wind Farm will be required to carry out compensation to mitigate its impact for all sites and features where an AEOI was not ruled out in the Appropriate Assessment (Appendix B of Scottish Government, 2024). Therefore, for those features, the net impact from Green Volt Offshore Wind Farm following compensation may be deemed to be zero. However, as this decision was published during the time that the in-combination assessments for the Array were undertaken in this RIAA, the in-combination totals for Green Volt Offshore Wind Farm have not been amended to reflect this requirement for compensation, and the predicted impact from Green Volt Offshore Wind Farm prior to compensation (as per Green Volt Offshore Wind Farm, 2023) have been included in the calculation of in-combination total impact values. Therefore, the totals presented in this RIAA for those features listed in paragraph 363 must be considered to have an extra element of precaution, as a result of the inclusion of impacts which will be compensated for. It is noted that the impacts from Green Volt Offshore Wind Farm alone tend to be a small proportion of the in-combination totals and therefore it is not anticipated that this degree of precaution would influence the conclusions and the determination of AEOI or no AEOI.  

5.5.2. Disturbance and Displacement

                        Operation and Maintenance Phase

  1. During the operational phase, seabirds may be impacted by a disturbance and/or displacement due to the physical presence of wind turbines, vessel traffic and helicopter activity. Disturbance and/or displacement may have consequent impacts on the survival or fitness of birds. If displacement limits seabird access to foraging areas, it can result in reduced energy intake and reduced foraging success. Displacement effects can also cause increased inter- and intra-specific competition for alternative foraging areas and prey resources.
  2. The displacement and subsequent mortality rates used for the Array are given in Table 5.3   Open ▸ , although for this in-combination assessment, only the lowest and highest approach are taken through to assess the total range of impacts. For other developments, the displacement and mortality rates are as described in the data source referenced in each case.
                        Buchan Ness to Collieston Coast SPA
Kittiwake (seabird assemblage component only)
  1. The source information regarding kittiwake disturbance mortality from other relevant projects is given in Table 5.62   Open ▸ .

 

Table 5.62:
Kittiwake Displacement Mortalities Apportioned to the Buchan Ness to Collieston Coast SPA from Other Relevant Projects

 Table 5.62: Kittiwake Displacement Mortalities Apportioned to the Buchan Ness to Collieston Coast SPA from Other Relevant Projects

 

  1. From this information, the various approaches have been consolidated into a “low” and a “high” estimate for the total in-combination impact. This is presented in Table 5.63   Open ▸ .

 

Table 5.63:
Kittiwake Displacement Mortalities Apportioned to the Buchan Ness to Collieston Coast SPA In-Combination Totals

Table 5.63: Kittiwake Displacement Mortalities Apportioned to the Buchan Ness to Collieston Coast SPA In-Combination Totals

 

  1. With a population of 22,590 breeding adults (Burnell et al., 2023), 7.8 to 20.3 additional mortalities represents a 0.035 to 0.090 percentage point increase in mortality rates. Therefore, PVA has been carried out both with and without Berwick Bank Offshore Wind Farm and for the high and low scenarios, to further assess the total in-combination impact.
  2. The PVA results are summarised in Table 5.64   Open ▸ . Full details are available in appendix 3B.
Table 5.64:
Summary of PVA Results for In-Combination Displacement Impacts on Kittiwake at the Buchan Ness to Collieston Coast SPA

Table 5.64: Summary of PVA Results for In-Combination Displacement Impacts on Kittiwake at the Buchan Ness to Collieston Coast SPA

 

  1. The kittiwake population of the Buchan Ness to Collieston Coast SPA has declined significantly between its citation level of 60,904 breeding adults and Seabird Census counts of 22,590 breeding adults (Burnell et al., 2023), and is assessed as being in “Unfavourable No Change” condition (NatureScot, ND). There have however been recent signs of slight recovery, with 13,547 AONs (27,094 individuals) recorded in 2023 (Tremlett et al, 2024).
  2. The PVA results show that the kittiwake population is expected to remain relatively stable under the counterfactual (no impact) scenario and also under all impact scenarios considered. The median Counterfactual of Growth Rate (CGR) is, for all scenarios, at least 0.999 which indicates the population growth rate declines no more than 0.1%. After 35 years (the expected lifespan of the Array), the Counterfactual of Population Size (CPS) ranges from 0.963 (with Berwick Bank Offshore Wind Farm; High approach to assessment) to 0.986 (without Berwick Bank Offshore Wind Farm; Low approach to assessment).
  3. Overall, therefore, the impact of displacement from the Array in combination with other projects is not of a magnitude that can be said to adversely affect the likelihood of the kittiwake population being maintained as a viable component of the site.

                        Breeding Seabird Assemblage

  1. Of the components of the seabird assemblage, kittiwake was the only species for which a potential LSE2 was identified. As detailed above, there is expected to be no significant impact on the kittiwake population. Therefore, it can also be concluded, beyond reasonable scientific doubt, that there is no potential for an AEOI to the seabird assemblage feature of the Buchan Ness to Collieston Coast SPA as a result of displacement from the Array in combination with other developments.