14. In-combination effects
14.1.1 In-combination effects arising from the draft Plan have been considered in the HRA Report. Consideration of in-combination effects included development between DPOs and / or other plans or projects with connectivity to the same qualifying interests of European/Ramsar sites.
14.1.2 The HRA Report assumed that OWF development would occur in all 17 DPOs (as a WCS) and thereby considered potential effects arising from development within any or all DPOs, in tandem with potential effects arising from other plans or projects. The HRA Report used the maximum realistic development scenarios (as set out above in this AA), as it is not possible to predict the degree of development which will occur (if any) within each DPO. The HRA Report assumed that development could occur potentially occur in any part of the DPO (although it is recognised that development will not take place across the entirety of any DPO).
14.1.3 The other plans and projects considered in the in-combination assessment are outlined in Annex 1 (Table 17) and Annex 2. Assessments completed for other currently consented or operational windfarms identified the following key impact pathways;
- Direct and indirect damage to habitats;
- Physical damage and mortality to species, especially birds, due to collision risk;
- Non-physical disturbance to species due to displacement effects, noise and vibration effects and effects from EMF; and
- Non-toxic contamination due to elevated turbidity.
14.1.4 The key concerns raised in relation to other plans and projects primarily relate to direct and indirect damage to habitat (within and adjacent to the OWF) and potential impacts to mobile species due to collision risk, displacement and disturbance (noise, visual and vibration). These impacts may occur during the survey, construction, operation and/or maintenance phases and may, therefore, overlap in terms of timing.
14.1.5 The direct and indirect effects to benthic habitats and species in the vicinity of individual projects are well-understood. These impacts are relatively localised and can be addressed/offset through mitigation measures, if required, if they result in an adverse effect on a European site or European marine site. Although DPOs do not directly overlap these sites, there is the potential for direct impacts to occur due to cable routing and landfall locations.
14.1.6 Further spatial-planning within DPOs at a project-level (in order to avoid or minimise impacts) and array design will be a key measure to mitigating potential impacts to qualifying interests and features.
14.1.7 The greatest risk of in-combination effects (between DPOs and with other existing/consented OWF) are for mobile features. There is the potential for AEOSI to occur for these receptors, particularly seabird qualifying interests, due to a variety of impact pathways and activities, during different phases of development. In particular, there is the potential for an AEOSI to occur for seabird colonies on the East and North East coasts due to in-combination displacement and collision risk impacts for a number of seabird species (as discussed above).
14.1.8 In-combination impacts with non-OWF projects (e.g. harbour redevelopment works) may also occur, for example as a result of prolonged periods of underwater noise associated with piling activity. Non-marine activities for developments may have the potential to impact river SACs, resulting in potential in-combination effects on Atlantic salmon, freshwater pearl mussel and otter interest features. Within the offshore environment, potential in-combination effects may occur where there are a number of developments over a range of sectors (e.g. fishing, oil and gas), resulting in impacts on habitats and foraging species. In addition, there is the potential for in-combination effects as a result of seismic survey activity (associated with oil and gas activity), which are generally of a greater magnitude than survey activity associated with OWF development.
14.2 Marine mammals
14.2.1 Key risks to marine mammals are considered to occur during the construction phase and, therefore, there is greater opportunity for project-level mitigation measures to minimise, reduce or avoid impacts (e.g. the requirement to prepare and adhere to Piling Strategies).
14.2.2 The HRA Report considered the SNCB responses to project-level HRAs for Inch Cape, Moray West, Seagreen, Neart na Gaoithe and Dounreay Tri. SNCB consultation responses have consistently indicated that, "compliance with consent conditions would be sufficient to result in no adverse effect on marine mammals as qualifying interests of designated sites, either alone or in-combination with other developments."
14.2.3 There is scope, however, for additive cumulative effect resulting from temporal overlap between construction works (e.g. underwater noise from piling activities) within the same region, as highlighted by JNCC in its consultation response (see Section 5). These in-combination effects could be mitigated via measures such as temporal sequencing of development to avoid additive effects, although such an approach could result in an extension to the duration of effects. Therefore, Scottish Ministers consider that these risks are most appropriately managed at a project-level, when further detail regarding the location, scale, duration and nature of activities can be provided and assessed. Furthermore, there is the potential for additive in-combination effects to occur as a result of oil and gas survey activity (e.g. seismic survey). The level of future activity cannot be predicted at this time and therefore, Scottish Ministers consider that these risks can only be appropriately and effectively managed at a project-level.
14.2.4 In its consultation response, SNH highlighted that it considers that development under the Plan could be facilitated by the conduct of regional strategic marine mammal surveys to inform consenting (rather than reliance on site-specific survey effort linked to specific projects which may be unable to characterise and quantify marine mammal usage of the proposed development area). These survey outputs could be used to inform modelling of population-level impacts and further Plan and project-level assessment. Since completion of the HRA Report, a report has been published which collates and presents the most up-to-date information on the abundance and distribution of marine mammal species in the Scottish Northern North Sea Region and Scottish Atlantic waters, with a specific focus on the DPOs. The report identifies data and evidence gaps and provides recommendations on how such gaps can be addressed. The information and recommendations presented in this report will be useful in informing further research and assessment, at both strategic and project-levels. Further recent research reports of relevance to future plan and project-level assessment have examined the use of dynamic energy budget models (and their potential for integration into the iPCoD framework) and parameterisation and sensitivity analysis for disturbance assessments.
14.2.5 Scottish Ministers therefore concluded that this Plan will not result in adverse effects on the marine mammal qualifying interests of designated sites, either alone or in-combination with other plans or projects, provided the mitigation measures set out in Section 4 are adhered to.
14.3.1 Key risks to ornithology interests are considered to occur during the operational phase (i.e. collision risk and displacement) and, therefore, there is less opportunity for project-level mitigation measures to minimise, reduce or avoid impacts (when compared to receptors most impacted during the construction phases, for example).
14.3.2 SNH advised that, in relation to DPOs E3 and NE2-NE6, due to concerns regarding the current "predicted in-combination impacts of existing and consented OWF on specific east coast SPAs and seabird species, no development should be permitted until and unless research and post consent monitoring of existing OWFs in eastern Scotland demonstrate that capacity for further development, with respect to SPA impacts, exists." Further, SNH advised that they are unable to conclude, at the Plan level, "no in-combination AEOSI arising from developments in these DPOs (E1 and E2) alongside those of existing consented OWF development in this region." JNCC and RSPB Scotland provided similar statements in their responses to the consultation on the draft Plan.
14.3.3 The HRA Report (section 10, page 259 onwards) provides an overview of the SNCB responses to recent OWF applications for large scale commercial OWF proposals in the Forth, Tay and Moray Firths. Consents have been granted for these proposals (and revised proposals) (Inch Cape, Neart na Gaoithe, Seagreen, Moray West) in the past 3 years. The assessments presented in the HRA Reports for Inch Cape, Neart na Goaithe and Seagreen utilised a WCS approach, looking at the existing consents granted in 2014 for the other OWF when considering in-combination impacts with the new (2017) proposals. The AAs prepared for these consents acknowledge the highly precautionary nature of these assessments when considering the potential for AEOSI. The concerns raised by the SNCBs are summarised briefly below (see Table 23, Page 260 of the HRA Report for further detail);
Table 16 SNCB responses to recent applications - Forth, Tay and Moray
Proposal: Moray West - Up to 85 WTG
SNH consultation response:
Objection - in-combination impacts with Moray East and Beatrice will have AEOSI for:
North Caithness Cliffs SPA - Kittiwake (collision risk); and
East Caithness Cliffs SPA - Great black-backed gull (collision risk)
Proposal: Seagreen Alpha and Bravo (Phase 1 (Revised)) - 120 WTG
SNH consultation response:
Objection - in-combination impacts with Neart na Gaoithe and Inch Cap, likely AEOSI for:
Forth Islands SPA - Black-legged kittiwake and northern gannet (collision risk); and
Fowlsheugh SPA - Black-legged kittiwake (collision risk)
Proposal: Inch Cape (Revised) - 72 WTG
SNH consultation response:
Objection - in-combination impacts with Seagreen and Neart na Gaoithe will have AEOSI for:
Forth Islands SPA - Black-legged kittiwake and northern gannet (collision risk) and razorbill (displacement); and
Fowlsheugh SPA - Black-legged kittiwake (collision risk) and razorbill (displacement)
Proposal: Neart na Gaoithe (Revised) - 54 WTG
SNH consultation response:
Objection - in-combination impacts with Seagreen and Inch Cape will have AEOSI for:
Forth Islands SPA - Black-legged kittiwake and northern gannet (collision risk) and razorbill (displacement);
Fowlsheugh SPA - Black-legged kittiwake (collision risk) and razorbill (displacement); and
St Abbs Head to Fast Castle SPA - Black-legged kittiwake (collision)
14.3.4 Based on the responses provided by the SNCBs to the HRA Report and the OWF applications outlined above, Scottish Minister consider that it is reasonable to conclude that further development in the Forth, Tay and Moray Firth regions will result in an AEOSI on kittiwakes as a qualifying feature of designated sites as a result of development within POs E3, NE2-NE4 and NE6. The HRA Report concluded that development within NE6 would result in an AEOSI on kittiwake as a qualifying feature of the Troup, Pennan and Lion's Heads SPA (as a result of existing development in the Moray Firth region) if development were to also occur in NE4 and NE5. Scottish Ministers have not chosen to include NE5 as a final PO and consideration has been given to whether this amends the conclusion of AEOSI for NE6 and the requirement for mitigation measures within NE6. Scottish Ministers have considered the implications of the updated foraging ranges (published after the completion of the HRA Report) and consider that the evidence presented justifies the continued application of the plan-level ornithological mitigation measure, in spite of the removal of NE6 (See earlier discussion, section 6).
14.3.5 Consideration has been given to potential in-combination effects as a result of development within PO E1 and E2, as a result of existing and consented OWF and other POs. These sites are generally beyond the mean max foraging ranges for Kittiwake and Razorbill, and therefore a LSE has not been identified. However, if the more precautionary measure of mean max foraging range in addition to one standard deviation is considered this would include more significant areas of the two sites. Based on this, although the extent to which developments in sites E1 and E2 would increase currently assessed cumulative impacts for east coast SPAs is unclear, the sites may overlap with the foraging distribution for some seabird species from east coast SPAs, especially the western parts of E1 and E2 that are more inshore. Therefore, whilst not classed in the same risk category as POs E3, NE2-NE4 and NE6, there will be a requirement for the collection and assessment of regional-level ornithology survey data (e.g. from digital aerial surveys) in this region. This would improve confidence in assessing the likely level of effects from collision, displacement, and barrier effects from any developments. The potential for LSE on east coast SPAs could be further understood by tracking studies of seabirds from these SPAs. Such information would improve confidence in assessing what proportion of any effects at the two sites should be apportioned to these SPAs and hence support project level HRA.
14.3.6 It is anticipated that further empirical data and research regarding seabird behaviour at sea, connectivity with colonies, foraging activity etc. will become available as further OWF development takes places and research is completed. These outputs may allow the current estimations of impact to be revised downwards, thereby facilitating further development in these regions, or may result in these estimations being revised upwards - indicating that no further carrying capacity exists. These conclusions regarding potential in-combination impacts have led to POs E3, NE2-NE4 and NE6 being classed as 'being subject to high levels of ornithological constraint' (Plan-level mitigation measure).
14.3.7 There is the potential for in-combination effects relating to collision risk for migratory birds, seabirds and non-seabirds, including the impact of multiple developments along the migratory passage route for Whooper Swan. A key migration flyway for Whooper Swan encompasses the Cumbrian coast, Solway Firth and North Channel and extends along the west coast of Scotland, with 50% of Whooper Swan estimated to fly at collision risk height. In-combination effects of PO W1 with proposed and operational OWF (Robin Rigg, Ormonde, Walney, Barrow and Burbo Bank) may increase collision risk and lead to an AEOSI for sites with the relevant qualifying interest. Further, development progressed as a result of The Crown Estate's Round 4 Leasing may result in further in-combination effects. As such, SNH has highlighted the need to consider updating the guidance for the assessment of collision risk for migratory bird species and this work will be progressed to inform future project-level assessment and the iterative plan review process.
14.3.8 Scottish Ministers therefore conclude that this Plan will not result in adverse effects on the ornithology qualifying interests of designated sites, either alone or in-combination with other plans or projects, provided the mitigation measures set out in Section 4 are adhered to.
14.4 Fish and freshwater pearl mussel qualifying interests
14.4.1 The HRA Report considered the SNCB responses to project-level HRAs for Inch Cape, Moray West, Seagreen, Neart na Gaoithe and Dounreay Tri. SNCB consultation responses have consistently indicated that, "compliance with consent conditions would be sufficient to result in no adverse effect on diadromous (migratory) fish and freshwater pearl mussel as qualifying interests of designated sites, either alone or in-combination with other developments."
14.4.2 There is scope, however, for additive cumulative effect resulting from temporal overlap between construction works (e.g. non-physical disturbance - piling noise and vibration) within the same region. These in-combination effects could be mitigated via measures such as temporal sequencing of development to avoid additive effects, although such an approach could result in an extension to the duration of effects. Therefore, Scottish Ministers consider that these risks are most appropriately managed at a project-level, when further detail regarding the location, scale, duration and nature of activities can be provided and assessed.
14.4.3 Scottish Ministers therefore concluded that this Plan will not result in adverse effects on the fish and freshwater pearl mussel qualifying interests of designated sites, either alone or in-combination with other plans or projects, provided the mitigation measures set out in Section 4 are adhered to.
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