Thanet Extension Offshore Wind Farm

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Thanet Extension Offshore Wind Farm

Received 12 September 2018
From Royal Society for the Protection of Birds (RSPB) (Royal Society for the Protection of Birds (RSPB))


Our involvement with Thanet Extension Offshore Wind Farm
The Royal Society for the Protection of Birds (the RSPB) has been involved with the Thanet Extension Offshore Windfarm (TEOW) project as a member of the Onshore Ecology and Offshore Ornithology Expert Topic Group (ETG).
Through this process we have endeavoured to inform the design of the scheme to minimise the risk of harm to its ornithological interests. Despite welcome constructive pre-application consultation and discussions, serious concerns with the offshore aspects of the Application remain. As it stands, we do not agree that the current assessment enables a conclusion of no adverse effect on the Special Protection Area (SPA) sites and their species.
Due to resource constraints, this representation comprises the RSPB’s final submission to the Examination however we reserve the right to add to or change this submission should the design of the scheme change and/or significant new information is submitted.

Onshore Ornithology
The RSPB is content that, on the basis of the data provided, this project will have no significant impact on the SPA, Ramsar site or SSSI bird features (1). For clarity we wish to add that whilst we agreed that little terns are unlikely to be affected, this is due to the location of the historical nesting site being at a safe distance from the development area and therefore there will be no risk of being affected, not because little terns are not currently nesting on site.
We are aware that the Kent Wildlife Trust will be raising other concerns relating to, among other things, intertidal habitat and we defer to them on those habitat concerns.

Offshore Ornithology
The proposed Thanet Extension Offshore Wind Farm (TEOWF) is 8km offshore from the Kent coast and surrounds the existing Thanet Offshore Wind Farm. The Outer Thames Estuary SPA, which is classified for its population of non-breeding red throated divers, is approximately 4km from the closest proposed Turbine location.
Key elements of the assessment of offshore ornithology, as presented in the Environmental Statement (ES), do not follow SNCB guidance or advice given by Natural England (NE), nor our suggested approach during consultation. We find that the information presented, especially in relation to displacement, to be unsatisfactory, in terms of presenting an assessment of impacts, which does follow recommended guidance, alongside that given in the ES. In addition, some apparent errors in the tables and text, and lack of detail in places, has resulted in an unclear assessment in relation to offshore ornithology, parts of which we consider to be inadequate. These concerns are set out below.

Displacement assessment
• Red throated diver: This is a species of key concern within the region that the proposed Thanet extension is situated. Several aspects of the assessment do not follow SNCB guidance (SNCBs (2017)), or the advice given by NE (which we support) during consultation.
Specifically, the rates of displacement (82% during construction and 73% during operation) and the spatial extent used (i.e. that consideration have been given to the windfarm area only without any buffer zone). This is justified on the basis of the evidence provided from post-construction monitoring (Royal Haskoning DHV, 2013). Whilst ‘local’ data and knowledge can be useful in informing an assessment, the report cited has limitations, for example the use of boat-based surveys and the limited buffer-size of the survey area. More robust sources of ‘local’ information, include the post-construction reporting from London Array (APEM, 2016); which shows evidence of displacement to at least 6km. We maintain that, in light of this and the wider evidence base suggesting that displacement of red throated divers goes beyond the wind farm footprint, a precautionary approach would be to follow SNCB guidance and assume that up to 100% of birds within the 4km buffer are subject to displacement during both construction and operation.
• Auks: The assessment for both razorbills and guillemots during construction and operation, also fails to follow SNCB guidance; both in relation to the spatial extent covered and displacement rates used. It is unclear (due to inconsistencies in the text/ table legend) if 500m or 1km buffers were used for razorbill but neither species was assessed using the 2km buffer recommended.
• Gannet: Again, SNCB guidance, to include birds within a 2km buffer, has not been followed.

Collision risk modelling
• Option 2 (using generic flight height distributions) of the Band model is presented within the ES chapter. It is preferable that site-specific data is used to inform collision risk (option 1); if available and robust. Specifically, the data collected during the Offshore Renewables Joint Industry Programme (ORJIP), study of collision and avoidance, which was conducted at Thanet Offshore Wind, are one potential source of site-specific data. We note that in Annex 4-4 these data were not used due to ‘ongoing uncertainties’ in relation to the Band model. Whilst we agree that the avoidance rates derived in this study are subject to such uncertainty, it is unclear why the flight height data could not be used. Greater detail, in relation to the ORJIP, historical and recent survey data is needed to explain why option 1 was not presented in the ES. Both options 1 and 2 are provided in Annex 4-4; it would therefore be helpful if an indication were given as to how reliable the figures given for option 1 are thought to be (if unreliable, it is unclear as to why they are presented).
• We do not agree with the use of revised Nocturnal Activity Factors in the CRM. For kittiwake and large gulls, there is no peer reviewed evidence for a change in the factor used. The current factor is derived from the expert opinion collected by Garthe and Hüppop (2004) and this use is endorsed by Band (2012). A review of seabird vulnerability to offshore wind farms (Furness et al., 2013) recommended that no changes be made to the nocturnal activity scores for these species, and an update, including the same authors (Wade et al., 2016) maintained this recommendation. For gannet, there is a peer reviewed paper with revised rates (Furness et al., 2018). While we welcome this review, we are concerned that the mortalities predicted using revised nocturnal activity rates for gannet are potentially underestimated, because they do not account for the fact that the timing of bird surveys might not coincide with peaks in foraging activity at first and last light (see Fig. 3 in Furness et al., 2018). As well as gannet, this is true for all other species concerned. In addition, the Band (2012) model considers the nocturnal period as between sunset to sunrise and so treats flight activity that occurs at twilight as being within the nocturnal flight period. The reduced factor, now used for gannet in the CRM, equates to 0% nocturnal activity. Evidence shows that gannet will forage at twilight, and so these flights are excluded when using the revised activity factor. All of the above means that the figures presented in the ES for collision risk may represent an underestimate for all species.

Cumulative and in-combination assessments
• Displacement: We have concerns with the methodological approach used to assess cumulative and in-combination displacement for red throated divers. To date, we have not been provided with sufficient detail to enable us to determine its robustness or suitability. Such detail is not provided in the ES or Annexes. For example, apparent inconsistencies in the predicted increase in background mortality in relation to the impact of ‘Thanet Extension alone’ on the Outer Thames Estuary SPA, presented in paragraph 11.4.12 (at 0.7%) and Table 12.13 (at 0.024%) of the Report to Inform the Appropriate Assessment (RIAA), are of concern and need further explanation.
• Collision: The in-combination assessment of collision impacts, within the RIAA, focuses on the contribution made by this extension application rather than the total impact ‘in-combination’ from across all sites.
Offshore ornithology impacts
• Red throated diver: Had SNCB guidance been followed, 696 divers would be subject to displacement impacts vs the 195 (construction) or 174 (operation) presented in the current assessment. We therefore consider the current magnitude of the impacts of displacement on red throated divers to represent a substantial underestimate.
Lack of clarity and the uncertainties surrounding the methods used for the cumulative assessment of displacement, mean we cannot currently agree with the conclusions in relation to the magnitude of this impact on red throated diver.
For the in-combination assessment of red throated diver displacement, presented in the RIAA, lack of detail relating to the methods, especially in relation to assessing the absolute impact (additional mortality) mean we cannot currently agree with the conclusion of “no potential for AEoI to the red-throated diver feature of the Outer Thames Estuary SPA in relation to in-combination disturbance and displacement effects”.
The consequences of changes in background mortality (even of a small magnitude) on red-throated diver populations are not currently well understood. In order for a clearer understanding of this, particularly in relation to the in-combination impacts, we recommend that a population model is run, and that counterfactual output metrics are presented (Cook & Robinson, 2017); pending the resolution of the issues surrounding the assessment methods used.
• Auks: For guillemots the annual estimate given in the ES of 552 individuals subject to displacement falls within the range of 336-782 that would have been estimated, if the recommended 30-70% displacement including a 2km buffer had been used. For razorbills this is less clear, as it was not possible to compare the annual displacement due to an apparent error in table 17 of annex 4-3. However; the ‘spring’ data for razorbills suggest displacement of 33 individuals (given in the ES) was an underestimate (38-87 would have been estimated if SNCB guidance were followed). Overall, it is likely that auk displacement has been underestimated (relative to the most precautionary 70% displacement), but less severely than for red throated divers.
• Collision risk: It is the RSPB opinion that the overall in-combination impact cannot be considered non-significant based only on an assessment of the magnitude of the extension application’s contribution. This is especially pertinent when it comes to gannets and kittiwakes since very large impacts have already been predicted on these SPA populations in the southern North Sea (for example see East Anglia Three, in-combination totals (Royal Haskoning DHV et al., 2015).

(1) Bird features include:
- Thanet coast &Sandwich bay SPA designated species: ruddy turnstone, European golden plover and little tern
- Thanet coast to Hacklinge Marshes SSSI: dunlin, oystercatcher, curlew, redshank, grey plover, sanderling, ringed plover, mallard, shelduck, brent goose
- Thanet coast &Sandwich bay Ramsar site: turnstone, ringed plover, golden plover, grey plover, sanderling and Lapland bunting

APEM (2016). Assessment of Displacement Impacts of Offshore Windfarms and Other Human Activities on Red-throated Divers and Alcids. Natural England Commissioned Reports, Number 227. APEM Ltd.
Band, W. (2012). Using a collision risk model to assess bird collision risks for offshore windfarms. Guidance document. SOSS Crown Estate.
Cook, A. S., & Robinson, R. A. (2017). Towards a framework for quantifying the population-level consequences of anthropogenic pressures on the environment: The case of seabirds and windfarms. Journal of environmental management, 190, 113.
Furness, R. W., Wade, H. M., & Masden, E. A. (2013). Assessing vulnerability of marine bird populations to offshore wind farms. Journal of environmental management, 119, 56-66.
Furness, R. W., Garthe, S., Trinder, M., Matthiopoulos, J., Wanless, S., & Jeglinski, J. (2018). Nocturnal flight activity of northern gannets Morus bassanus and implications for modelling collision risk at offshore wind farms. Environmental Impact Assessment Review, 73, 1-6.
Garthe, S., & Hüppop, O. (2004). Scaling possible adverse effects of marine wind farms on seabirds: developing and applying a vulnerability index. Journal of applied Ecology, 41(4), 724-734.
Royal Haskoning DHV (2013). Thanet Offshore Wind Farm Ornithological Monitoring 2012-2013 (Post-construction Year 3). Royal Haskoning DHV Report for Vattenfall Wind Power Limited.
Royal Haskoning DHV, MacArthur Green, & APEM (2015). East Anglia THREE: Information for Habitat Regulations Assessment. Report for Vattenfall Wind Power Limited & Scottish Power Renewables.
SNCBs (2017) Joint SNCB Interim Displacement advice note.
Wade, H. M., Masden, E. A., Jackson, A. C., & Furness, R. W. (2016). Incorporating data uncertainty when estimating potential vulnerability of Scottish seabirds to marine renewable energy developments. Marine Policy, 70, 108-113.