5 Data Sources
This section summarises the main data sources used to characterise the shipping and navigation baseline relative to the Proposed Development.
5.1 Summary of Data Sources
The main data sources used in assessing the shipping and navigation baseline relative to the Proposed Development are outlined in Table 5.1 Open ▸ .
Table 5.1 Data Sources Used to Inform Shipping and Navigation Baseline
5.2 Vessel Traffic Surveys
The vessel traffic surveys were undertaken in agreement with the MCA and NLB. Two 14-day AIS, radar, and visual observation surveys undertaken in summer 2022 (2 to 16 August 2022) and winter 2021 (11 to 24 January 2021) have been considered within the baseline for a total of 28 full days, with an earlier survey undertaken in summer 2020 and long-term dataset from 2019 used as validation (see Appendix E and Appendix F).
A number of vessel tracks recorded during the Proposed Development array area survey periods were classified as temporary (non-routine), such as the tracks of the survey vessel, other non-routeing survey vessels and vessels associated with the construction of Neart na Gaoithe (NnG) and Seagreen. These have therefore been excluded from the analysis.
The dataset is assessed in full in section 10.
5.3 Long-Term Vessel Traffic Data
Long-term vessel traffic data consisting of AIS covering 12 months in 2019 was collected from coastal receivers. Taking into account the distance offshore of the Proposed Development array area, the long-term vessel traffic data is considered to be comprehensive for the Proposed Development array area shipping and navigation study area. The assessment of this dataset allowed seasonal variations to be captured and any tangible effects of the COVID-19 pandemic to be observed.
The dataset is assessed in full in Appendix E.
5.4 Data Limitations
5.4.1 Automatic Identification System Data
For the purposes of the NRA, it has been assumed that vessels under an obligation to broadcast information via AIS have done so, both in the vessel traffic surveys and long-term vessel traffic data. It has also been assumed that the details broadcast via AIS (such as vessel type and dimensions) are accurate unless clear evidence to the contrary was identified during Anatec’s thorough quality assurance of the data.
5.4.2 Vessel Traffic Data for Proposed Development Export Cable Corridor
The MCA and NLB were content with the methodology for vessel traffic data collection. This method used only the AIS dataset to characterise vessel movements within the Proposed Development export cable corridor shipping and navigation study area. Consequently, this dataset has limitations associated with non-AIS targets.
5.4.3 COVID-19 Pandemic
It is widely accepted that the COVID-19 pandemic has had a substantial effect on shipping movements globally. Therefore, the vessel traffic survey data collected in winter 2021 may be influenced by COVID-19 pandemic. However, in line with best practices the Applicant has agreed the approach to data collection with relevant stakeholders, including the MCA.
Additionally, long-term vessel traffic data predating the COVID-19 pandemic has been used as a secondary source for characterising vessel traffic movements. A 12-month dataset covering 2019 has been referenced where relevant in the characterisation of the vessel traffic baseline. Analysis of the dataset in full is presented in Appendix E.
5.4.4 Historical Incident Data
Although all UK commercial vessels are required to report accidents to the Marine Accident Investigation Branch (MAIB), this is not mandatory for non-UK vessels unless they are in a UK port, within 12 nm of territorial waters (noting that the Proposed Development array area is located approximately 18 nm offshore at the closest point), or carrying passengers to a UK port. There are also no requirements for non-commercial recreational craft to report accidents to the MAIB.
The RNLI incident data cannot be considered comprehensive of all Incidents in the shipping and navigation study areas. Although hoaxes and false alarms are excluded, any incident to which a RNLI resource was not mobilised has not been accounted for in this dataset.
5.4.5 United Kingdom Hydrographic Office Admiralty Charts
During consultation, input has been sought from relevant stakeholders regarding the navigational features baseline. Navigational features are based upon the most recently available UKHO Admiralty Charts and Sailing Directions at the time of writing.
6.1 Proposed Development Boundaries
6.1.1 Proposed Development Array Area
The Proposed Development array area is located approximately 30 nm (56 km) east of the entrance to the Firth of Forth, largely covering the Marr Bank in the western half, and partially covering the Berwick Bank at the south-eastern extent. The total area covered by the Proposed Development array area is approximately 294 square nautical miles (nm2) (1,008 square kilometres (km2)) with water depths ranging between 34 and 64 m below Chart Datum (CD).
All surface piercing structures (wind turbines and offshore substation platforms) will be located entirely within the Proposed Development array area, inclusive of blade overfly. The coordinates defining the boundary of the Proposed Development array area are illustrated in Figure 6.1 Open ▸ and provided in Table 6.1 Open ▸ . During no phase of the development will the Proposed Development array area be designated as an Area to Be Avoided (ATBA), with navigation only restricted where Safety Zones are active (see section 17).
Figure 6.1 Proposed Development Array Area Coordinates
Table 6.1 Coordinates for the Proposed Development Array Area
6.1.1.1 Refinement of the Proposed Development Array Area
The Proposed Development array area has been refined from that considered in the Scoping Report for the 2020 Berwick Bank (RPS Energy, 2020), the 2021 Scoping Report (RPS Energy (2021) and at the time of the first Hazard Workshop in September 2021. These refinements are presented in Figure 6.2 Open ▸ .
Figure 6.2 Refinement of the Proposed Development Array Area
Following the Scoping Report for the 2020 Berwick Bank, the more pointed south-eastern corner was softened, primarily due to concerns raised by shipping and navigation stakeholders. Additionally, the north-western section of the Proposed Development array area – part of the original proposed Marr Bank Wind Farm development, which was combined with the 2020 Berwick Bank to form the current Berwick Bank Wind Farm – was amended to create a gap between the Proposed Development array area and Seagreen and increase the width of the gap between the Proposed Development array area and Inch Cape. This version of the Proposed Development array area was presented at the first Hazard Workshop.
Following the Scoping Report and the first Hazard Workshop, the north-western section of the Proposed Development array area was again amended to increase the width of the gap between the Proposed Development array area and Seagreen and the Proposed Development array area and Inch Cape. The south-western and south-eastern sections of the Proposed Development array area were also refined further. This version of the Proposed Development array area was presented at the second Hazard Workshop and is considered throughout this NRA.
The Proposed Development array area represents a 23% reduction in extent from that considered in the Scoping Report and a 30% reduction in extent from that considered in the Scoping Report for the 2020 Berwick Bank (when considering the Berwick Bank and Marr Bank developments combined).
6.1.2 Proposed Development Export Cable Corridor
The Proposed Development export cable corridor runs between the southern boundary of the Proposed Development array area and the landfall point at Skateraw. The total area is approximately 49 nm2 (168 km2) with water depths within the Proposed Development export cable corridor ranging between 3 and 64 m below CD.
The offshore export cables will be located fully within the Proposed Development export cable corridor. The key coordinates defining the boundary of the Proposed Development export cable corridor are illustrated in Figure 6.3 Open ▸ and provided in Table 6.2 Open ▸ .
Figure 6.3 Proposed Development Export Cable Corridor Key Coordinates
The Proposed Development export cable corridor has also been refined from that considered in the first Hazard Workshop, with a second landfall location at Thorntonloch removed. A secondary export cable option to Blyth (the Cambois connection) is also under consideration and is considered as part of the cumulative risk assessment (see section 14.1.3).
Table 6.2 Key Coordinates for the Proposed Development Export Cable Corridor
6.2 Surface Infrastructure
6.2.1 Indicative Array Layout
Up to 317 surface structures will be installed within the Proposed Development array area, consisting of up to 307 wind turbines and 10 offshore substation platforms. The final positions of surface structures have not yet been defined, but for the purposes of the NRA an indicative worst case array layout has been determined and is presented in Figure 6.4 Open ▸ .
Figure 6.4 Overview of Indicative Worst Case Array Layout for Shipping and Navigation
The indicative worst case array layout consists of a full build out of the Proposed Development array area to maximise the spatial extent of vessel deviations and the maximum possible number of surface structures to maximise exposure for passing (or adrift) vessels.
The minimum spacing within the PDE is 1,000 m, however with the indicative layout relevant for shipping and navigation this spacing varies as follows. The indicative array layout includes at least two lines of orientation[3] for wind turbines with a minimum spacing between wind turbines (measured centre-to-centre) of 1,265 m. The minimum spacing within the PDE is 1,000 m, with this spacing considered within the risk assessment where appropriate. The offshore substation platforms are evenly spaced between the wind turbine rows, giving an overall minimum spacing between structures for the indicative array layout (measured centre-to-centre) of 1,265 m, in the northeast-southwest direction. The minimum spacing between structures in a northwest-southeast orientation is 1,780 m.
6.2.2 Wind Turbines
The wind turbines within the indicative array layout each have a maximum rotor diameter of 222 m and maximum blade tip height (above LAT) of between 257 and 267 m. However, the maximum design scenario values for shipping and navigation are associated with the largest possible wind turbines (which would not be used for the indicative array layout). These are 310 m for rotor diameter and between 307 and 355 m for maximum blade tip height.
Piled jackets and suction caisson jackets foundations have been considered as the maximum design scenario for shipping and navigation as these foundation types provide the maximum structure dimension at the sea surface, and therefore maximise exposure for passing (or adrift) vessels. The maximum design scenario for the wind turbines, which assume use of a piled jacket or suction caisson jacket foundation design, are provided in Table 6.3 Open ▸ .
Table 6.3 Wind Turbines Maximum Design Scenario for Shipping and Navigation
Floating foundations are not included in the PDE. Further descriptions of the foundation types under consideration are provided in volume 2, chapter 3.
6.2.3 Offshore Substation Platforms
The offshore substation platforms will be installed on piled jackets or suction caisson jacket foundations, with two types of substation under consideration – High Voltage Alternating Current (HVAC) and High Voltage Direct Current (HVDC). For HVAC offshore substation platforms the maximum topside dimensions are 39×39 m and for HVDC offshore substation platforms are 100×85 m.
6.3 Subsea Infrastructure
Three types of subsea cables will be installed: inter-array cables, interconnector cables and offshore export cables. Each category of subsea cables is summarised in the following subsections.
6.3.1 Inter-Array Cables
The inter-array cables will be fully installed within the Proposed Development array area to connect individual wind turbines to each other and to the offshore substation platforms. Up to 661 nm (1,225 km) of inter-array cables will be required with up to 78 crossings, although the final length and number of crossings will depend upon the final array layout. The maximum height of inter-array cable crossings will be 3.5 m.
6.3.2 Interconnector Cables
The interconnector cables will be fully installed within the Proposed Development array area to provide interlink connections between the offshore substation platforms. Up to 46 nm (85 km) of interconnector cables will be required, although the final length will depend upon the final array layout.
6.3.3 Offshore Export Cables
The offshore export cables will be installed within the Proposed Development export cable corridor to carry the electricity generated by the wind turbines to the landfall location (Skateraw). Up to eight offshore export cables and 471 nm (872 km) of offshore export cables will be required with up to 16 crossings. The maximum height of offshore export cables crossings will be 3.5 m.
6.3.4 Cable Burial and Protection
Where available, the primary means of cable protection will be by seabed burial. The extent and method by which the subsea cables will be buried will depend on the results of a detailed seabed survey of the final subsea cable routes and associated cable burial risk assessment. However, a minimum burial depth of 0.5 m for all subsea cables associated with the Proposed Development is assumed as part of the maximum design scenario.
Where cable burial is not possible, alternative cable protection methods may be deployed which will be determined within the cable burial risk assessment. These methods may include a combination of rock installation, concrete mattresses, rock bags, cast iron shells, sleeving and Cable Protection Systems (CPS). It is assumed that up to 15% of all subsea cables may require cable protection as part of the maximum design scenario with a maximum cable protection height of 3 m and width of 20 m (excluding crossings).
6.4 Timescales
6.4.1 Construction Phase
The offshore construction phase will indicatively commence in December 2025, last for up to eight years, and be undertaken in up to three phases.
6.4.2 Operation and Maintenance Phase
The operation and maintenance phase will last for up to 35 years.
6.4.3 Decommissioning Phase
The decommissioning phase will generally be the reverse of the construction phase in terms of duration, vessel types and vessel numbers. It is anticipated that all sea surface structures will be completely removed above the seabed and all subsea cables will be left in situ (although best practice will be followed at the time of decommissioning).
6.5 Vessel and Helicopter Numbers
This subsection provides an overview of maximum vessel numbers for each activity and phase of the Proposed Development. Details relating to the routes to be undertaken by vessels associated with the Proposed Development are not available at this stage but will be defined as part of marine coordination (see section 6.5.2). Return trips may not occur uniformly throughout each phase depending on factors such as relevant activities and crew transfer times.
6.5.1 Construction Phase
Up to 10,964 return trips by construction vessels (excluding site preparation activities) may be made throughout the construction phase. The maximum number of vessel types associated with construction phase activities are summarised in Table 6.4 Open ▸ .
Table 6.4 Maximum Vessel Numbers per Vessel Type for Construction Phase
Additionally, up to 3,214 return trips by up to 13 helicopters may be made during the construction phase.
6.5.2 Operation and Maintenance Phase
Up to 2,323 return trips per year by operation and maintenance vessels may be made throughout the operation and maintenance phase.[4] The maximum number of vessel types associated with the operation and maintenance phase are summarised in Table 6.5 Open ▸ .
Table 6.5 Maximum Vessel Numbers per Vessel Type for Operation and Maintenance Phase
During both the construction and operation and maintenance phases, logistics will be managed by a marine coordination team. An integrated Health, Safety and Environment (HSE) management system will be in place to ensure control of all vessels and their respective works. The Project will be operational 24/7.
6.5.3 Decommissioning Phase
As noted in section 6.4.3, the decommissioning phase will generally be the reverse of the construction phase including in terms of vessel types and vessel numbers.
6.6 Maximum Design Scenario
The maximum design scenario for each shipping and navigation hazard is provided in Table 6.6 Open ▸ and is based on the parameters described in the previous subsections.
Table 6.6 Maximum Design Scenario by Hazard for Shipping and Navigation
7 Navigational Features
A plot of navigational features in proximity to the Proposed Development array area and export cable corridor is presented in Figure 7.1 Open ▸ . Each of the features shown is discussed in the following subsections and has been identified using the most detailed UKHO Admiralty Charts available.
Figure 7.1 General Overview of Navigational Features in Proximity to the Proposed Development
7.1 Other Offshore Wind Farm Developments
A plot of nearby other offshore wind farm developments in proximity to the Proposed Development is presented in Figure 7.2 Open ▸ , colour-coded by development status.
Figure 7.2 Offshore Wind Farm Developments in Proximity to the Proposed Development
The closest offshore wind farm developments to the Proposed Development array area are Seagreen Offshore Wind Farm (hereafter referred to as ‘Seagreen’) located approximately 2.7 nm to the north, and Inch Cape Offshore Wind Farm (hereafter referred to as ‘Inch Cape’) located approximately 4.1 nm to the west. It is noted that these distances are measured between the consented boundaries of the respective developments[5].
Seagreen is under construction with the construction buoyage deployed in September 2021 and the development expected to be fully commissioned in November 2023 (Seagreen Wind Energy Ltd., 2020). A variation to development parameters for Inch Cape was consented in June 2019, with CfD secured in July 2022 (Department for Business, Energy and Industrial Strategy (BEIS), 2022).
NnG is also located in the region, approximately 8.8 nm to the west of the Proposed Development array area. NnG is under construction with the construction buoyage deployed in May 2020 and the development expected to be fully commissioned in November 2022 (EDF, 2020).
Other offshore wind farm developments in the region include Kincardine (operational), European Offshore Wind Deployment Centre (EOWDC) (operational), Forthwind (scoped) and ScotWind sites Cluaran Deas Ear, Morven, Bellrock, Campion, Mara Mhor, and Ossian (all areas of search). Further details are included in section 14.1.
7.2 Ports and Related Services
A plot of nearby ports and harbours is presented in Figure 7.3 Open ▸ . It is noted that there are other ports and harbours within the Firth of Forth not labelled in Figure 7.3 Open ▸ , but for clarity only the more prominent ports and harbours are shown. Ports and harbours within the Firth of Forth are considered collectively throughout the NRA.
Figure 7.3 Ports and Harbours in Proximity to the Proposed Development
The closest port or harbour to the Proposed Development array area is Arbroath Harbour, located approximately 23 nm to the north-west, on the Angus coast. The Admiralty Sailing Directions describe Arbroath as “mainly a fishing port used by small and medium-sized fishing vessels” which is also occupied by a yacht marina (UKHO, 2021).
Montrose Port is located approximately 24 nm to the north-west on the Angus coast and is described by the Admiralty Sailing Directions as “a commercial port and a supply base for the offshore oil industry” (UKHO, 2021).
7.2.1 Ports and Harbours within the Firth of Forth
The Firth of Forth contains many ports and harbours of varying sizes, including:
- Aberdour;
- Anstruther;
- Braefoot Bay;
- Burntisland;
- Cockenzie;
- Crail;
- Grangemouth;
- Granton;
- Leith;
- Methil;
- North Berwick;
- North Queensferry;
- Pettycur Pier;
- Pittenweem;
- Rosyth; and
- St. Monans.
Grangemouth is “the largest port in Scotland” and handles “all types of vessels, including container vessels, tankers and LPG carriers” (UKHO, 2021). Rosyth, Leith and Braefoot Bay are also prominent ports which handle a range of vessel types.
A VTS – the Forth and Tay Navigation Service – is operated from Grangemouth with “all vessels of 50 GT and over required to report on passing the eastern limit and at all subsequent reporting points” (UKHO, 2021). Forth Ports have confirmed during consultation that the VTS does not extend as far out as the Firth of Forth offshore wind farm developments, including the Proposed Development array area. Forth Ports do not advise vessel traffic as far offshore as the Proposed Development array area.
7.2.2 Vessel Arrivals
The number of vessel arrivals at ports in the region, as reported by the Department for Transport (DfT), is presented in Figure 7.4 Open ▸ . These statistics exclude some vessel movements which occur within port or harbour limits, but nevertheless give a clear indication of the relative traffic levels and trends.
Figure 7.4 Vessel Arrivals to Commercial Ports in Proximity to the Proposed Development
As a collective, ports in the Forth are the most frequented commercial ports in the area followed by Aberdeen, although both ports have experienced a slight downward trend in vessel arrivals in recent years. In the case of Aberdeen, this may be partially related to the effects of COVID-19 pandemic.
7.3 Aids to Navigation
A plot of nearby aids to navigation is presented in Figure 7.5 Open ▸ . The information provided in Figure 7.5 Open ▸ and the following text is current as of August 2022.
Figure 7.5 Aids to Navigation in Proximity to the Proposed Development
There are no aids to navigation located within the Proposed Development array area – there are, however, scientific buoys and Light Detection and Ranging (Lidar) equipment present to gauge readings.
There is one aid to navigation located within the Proposed Development export cable corridor, a special mark situated in the approaches to Torness Power Station at the Skateraw landfall location.
There is a group of nine aids to navigation located west of the Proposed Development array area. These form the construction buoyage for NnG, and were deployed in May 2020, as confirmed by NLB during consultation. They are expected to be removed following the commissioning of the development, anticipated in November 2022 (EDF, 2020). Similarly, there is a group of 13 aids to navigation north of the Proposed Development array area that form the construction buoyage for Seagreen that were deployed in September 2021 and expected to be removed in September 2023 post-commissioning of the development.
The Inch Cape Met Mast and Bell Rock Lighthouse, both located west of the Proposed Development array area, also serve as aids to navigation.
7.4 Anchorage Locations
The majority of anchorage locations in the region are located within the Firth of Forth, where there are numerous designated anchorages and small vessel anchorages. Outside the Forth, there are designated anchorage points in close proximity to various coastal ports and harbours including off Dunbar, between St. Abbs and Eyemouth, off St. Andrews and in Lunan Bay to the south of Montrose.
The closest anchorage location to the Proposed Development array area is the designated anchorage point between St. Abbs and Eyemouth located approximately 19 nm to the south-west. The closest anchorage location to the Proposed Development export cable corridor is the designated anchorage off Dunbar located approximately 3.5 nm to the west of the Skateraw landfall location.
7.5 Military Practice and Exercise Areas
Military Practice and Exercise Areas (PEXA) close to the Proposed Development array area are presented in Figure 7.6 Open ▸ .
Figure 7.6 MoD Practice Areas in Proximity to the Proposed Development (Marine Scotland, 2019)
There are two MoD naval PEXAs located within the Outer Firth of Forth (X5641 and X5642), with area X5642 overlapping the Proposed Development array area. There is also a firing practice area off the Northumberland coast (Druridge Bay) located approximately 19 nm to the south of the Proposed Development array area, covering an area of approximately 2,300 nm2.
In addition, there is a smaller firing range (Barry Buddo) located approximately 24 nm to the west of the Proposed Development array area, at the mouth of the River Tay.
No restrictions are placed on the right to transit a military PEXA at any time, although mariners are advised to exercise caution. Exercises and firing only occur when the area is considered to be clear of all shipping.
There are not anticipated to be any hazards to shipping and navigation users associated with military PEXAs, although military vessels are considered as part of the baseline characterisation of vessel traffic movements in section 10.
7.6 Charted Wrecks
A plot of charted wrecks is presented in Figure 7.7 Open ▸ . Charted wrecks are those detailed on UKHO Admiralty Charts and are considered to pose a risk to surface navigation or subsea operations. Further details relating to wrecks are provided in volume 4, appendix 22 and the Marine Archaeology Technical Report which accompanies the Application.
Figure 7.7 Wrecks and Obstructions in Proximity to the Proposed Development
There are 10 charted wrecks located within the Proposed Development array area, with the shallowest at 35 m below CD, in the north-west of the Proposed Development array area. There are three charted wrecks located within the Proposed Development export cable corridor, all in the nearshore area.