Increased vessel to vessel collision risk resulting from displacement (third party to third party) | Construction | - buoyed construction area around maximum extent of Array;
- 500 m safety zones around structures where active construction works are ongoing, 50 m otherwise up until commissioning of the Array;
- up to 265 floating wind turbines, with up to 6 mooring lines each;
- floating wind turbine foundations, 130 m x 110 m;
- up to 3 large OSPs, and 12 smaller satellite OSPs;
- large OSP topside of 121 m x 89 m and smaller satellite OSP topside of 41 m x 37 m;
- construction phase up to 8 years; and
- up to 1,497 km in total Array cable length (inter-array and interconnector cables).
| Largest possible extent of site boundary and structure size plus greatest duration resulting in the maximum effect on vessel displacement. |
Operation and maintenance | - full build out of site boundary;
- 500 m safety zones around major maintenance works;
- operational lifespan of up to 35 years;
- up to 265 floating wind turbines;
- wind turbine floating foundations, 130 m x 110 m;
- up to three large OSPs, and 12 smaller satellite OSPs;
- large OSP topside of 121 m x 89 m and smaller satellite OSP topside of 41 m x 37 m; and
- up to 1,497 km in total Array cable length (inter-array and interconnector cables).
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Decommissioning | - anticipated that all floating structures will be completely removed;
- removal of mooring lines and dynamic cables;
- inter-array and interconnector cables may be left in situ (other than dynamic sections); and
- decommissioning sequence will generally be the reverse of the construction sequence and involve similar types and numbers of vessels and equipment.
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Displacement from adverse weather routeing | All phases | As for ‘Increased vessel to vessel collision risk resulting from displacement (third party to third party)’ - see above. | Largest possible extent of site boundary and structure size plus greatest duration resulting in the maximum effect on vessel displacement from adverse weather routeing. |
Increased vessel to vessel collision risk resulting from displacement (third party to Array vessels) | Site preparation and construction | - buoyed construction area around maximum extent of Array;
- up to 265 floating wind turbines, with up to 6 mooring lines each;
- up to 3 large OSPs, and 12 smaller satellite OSPs;
- construction phase up to 8 years;
- up to 1,497 km in total Array cable length (inter-array and interconnector cables); and
- up to 7,902 vessel return trips during site preparation and construction phases.
| Maximum number of project vessels and movements leading to largest collision risk. |
Operation and maintenance | - full build out of site boundary;
- operational lifespan of up to 35 years;
- up to 265 floating wind turbines;
- floating wind turbine foundations, 130 m x 110 m;
- up to 3 large OSPs, and 12 smaller satellite OSPs;
- large OSP topside of 121 m x 89 m and smaller satellite OSP topside of 41 m x 37 m; and
- up to 508 vessel trips per year for operation and maintenance.
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Decommissioning | - anticipated that all floating structures will be completely removed;
- removal of mooring lines and dynamic cables;
- inter-array and interconnector cables may be left in situ (other than dynamic sections); and
- decommissioning sequence will generally be the reverse of the construction sequence and involve similar types and numbers of vessels and equipment.
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Vessel to structure allision risk | Construction | - buoyed construction area around maximum extent of Array;
- up to 265 floating wind turbines, with up to 6 mooring lines each;
- floating wind turbine foundations, 130 m x 110 m;
- up to 3 large OSPs and 12 smaller satellite OSPs;
- large OSP topside of 121 m x 89 m and smaller satellite OSP topside of 41 m x 37 m; and
- construction phase up to 8 years.
| Largest possible extent of site boundary, greatest number of surface structures and maximum associate dimensions, plus greatest duration resulting in the maximum effect on vessel to structure allision risk. |
Operation and maintenance | - full build out of site boundary;
- operational lifespan of up to 35 years;
- up to 265 floating wind turbines;
- floating wind turbine foundations, 130 m x 110 m; and
- up to 3 large OSPs, and 12 smaller satellite OSPs;
- large OSP topside of 121 m x 89 m and smaller satellite OSP topside of 41 m x 37 m.
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Decommissioning | - anticipated that all floating structures will be completely removed; and
- decommissioning sequence will generally be the reverse of the construction sequence and involve similar types and numbers of vessels and equipment.
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Reduced access to local ports and harbours | All phases | As for ‘Increased vessel to vessel collision risk resulting from displacement (third party to Array Vessels)’ - see above. | Maximum number of project vessels and movements leading to largest potential impact on port access. |
Loss of station | Construction | - up to 265 floating wind turbines;
- floating wind turbine foundations, 130 m x 110 m;
- up to 3 large OSPs and 12 smaller satellite OSPs;
- large OSP topside of 121 m x 89 m and smaller satellite OSP topside of 41 m x 37 m; and
- construction phase up to 8 years.
| Maximum number of wind turbines with greatest surface dimensions leading to largest loss of station risk. |
Operation and maintenance | - full build out of site boundary;
- operational lifespan of up to 35 years;
- up to 265 floating wind turbines; and
- floating wind turbine foundations, 130 m x 110 m.
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Decommissioning | - anticipated that all floating structures will be completely removed; and
- decommissioning sequence will generally be the reverse of the construction sequence and involve similar types and numbers of vessels and equipment.
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Reduction of underkeel clearance as a result of subsea infrastructure | Construction | - buoyed construction area around maximum extent of Array;
- 500 m safety zones around structures where active construction works are ongoing, 50 m otherwise up until commissioning of wind farm;
- up to 265 floating wind turbines, with 6 mooring lines each;
- mooring line connection point 5 m below surface, angle of descent of 82 degrees from horizontal;
- up to 3 large OSPs and 12 smaller satellite OSPs;
- up to 1,497 km in total Array cable length (inter-array and interconnector cables);
- dynamic inter-array cables with buoyancy modules;
- maximum burial depth of 3 m, minimum target burial depth of 0.4 m subject to CBRA
- cable protection required for up to 20% of inter-array cables and up to 30% of interconnector cables;
- maximum cable protection height of 3 m and width of 20 m for all subsea cables (excluding crossings);
- up to 12 inter-array and 12 interconnector cable crossings, with a maximum height of 4 m; and
- construction phase up to 8 years.
| Maximum number of mooring lines, plus longest length of inter-array and interconnector cables. |
Operation and maintenance | As for the construction phase. |
Decommissioning | - anticipated that all floating structures will be completely removed;
- removal of mooring lines and dynamic cables;
- inter-array and interconnector cables may be left in situ (other than dynamic sections); and
- decommissioning sequence will generally be the reverse of the construction sequence and involve similar types and numbers of vessels and equipment.
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Anchor interaction with subsea cables (including dynamic cabling) | Construction | - buoyed construction area around maximum extent of Array;
- 500 m safety zones around structures where active construction works are ongoing, 50 m otherwise up until commissioning of the Array;
- up to 265 floating wind turbines;
- up to three large OSPs, and 12 smaller satellite OSPs;
- construction phase up to 8 years;
- up to 1,497 km in total array cable length (inter-array and interconnector cables);
- dynamic inter-array cables with buoyancy modules; and
- maximum burial depth of 3 m, minimum target burial depth of 0.4 m subject to CBRA.
| Maximum length of inter-array and interconnector cables. |
Operation and maintenance | - full build out of site boundary;
- 500 m safety zones around major maintenance works;
- up to 265 floating wind turbines;
- up to 3 large OSPs, and 12 smaller satellite OSPs;
- operational lifespan of up to 35 years;
- up to 1,497 km in total Array cable length (inter-array and interconnector cables);
- dynamic inter array cables with buoyancy modules; and
- maximum burial depth of 3 m, minimum target burial depth of 0.4 m subject to CBRA.
|
Decommissioning | - anticipated that all floating structures will be completely removed;
- removal of mooring lines and dynamic cables;
- inter-array and interconnector cables may be left in situ (other than dynamic sections); and
- decommissioning sequence will generally be the reverse of the construction sequence and involve similar types and numbers of vessels and equipment.
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Anchor interaction with mooring lines | Construction | - buoyed construction area around maximum extent of Array;
- 500 m safety zones around structures where active construction works are ongoing, 50 m otherwise up until commissioning of wind farm;
- up to 265 floating wind turbines, with up to 6 mooring lines each;
- mooring line connection point 5 m below surface, angle of descent of 82 degrees from horizontal;
- mooring line radius up to 700 m; and
- construction phase up to 8 years.
| Maximum number of mooring lines. |
Operation and maintenance | - full build out of site boundary;
- 500 m safety zones around major maintenance works;
- up to 265 floating wind turbines, with up to 6 mooring lines each;
- mooring line connection point 5 m below surface, angle of descent of 82 degrees from horizontal;
- mooring line radius up to 700 m; and
- operational lifespan of up to 35 years.
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Decommissioning | - anticipated that all floating structures will be completely removed;
- removal of mooring lines and dynamic cables; and
- inter-array and interconnector cables may be left in situ (other than dynamic sections).
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Reduction in SAR Capability | Construction | - 500 m safety zones around structures where active construction works are ongoing, 50 m otherwise up until commissioning of the Array;
- up to 265 floating wind turbines;
- floating wind turbine foundations, 130 m x 110 m;
- up to 3 large OSPs, and 12 smaller satellite OSPs;
- large OSP topside of 121 m x 89m;
- smaller satellite OSP topside of 41 m x 37m;
- up to 1,497 km in total Array cable length (inter-array and interconnector cables);
- up to 7,902 vessel return trips during site preparation and construction phases; and
- construction phase up to 8 years.
| Largest possible extent of site boundary, greatest number of vessel activities, greatest number of surface structures and greatest duration resulting in the maximum effect on emergency response capability. |
Operation and maintenance | - full build out of site boundary;
- 500 m safety zones around major maintenance works;
- up to 265 floating wind turbines;
- floating wind turbine foundations, 130 m x 110 m;
- up to 3 large OSPs, and 12 smaller satellite OSPs;
- large OSP topside of 121 m x 89 m;
- smaller satellite OSP topside of 41 m x 37 m;
- operational lifespan of up to 35 years;
- up to 1,497 km in total Array cable length (inter-array and interconnector cables); and
- up to 508 vessel trips per year for the operation and maintenance phase.
|
Decommissioning | - anticipated that all floating structures will be completely removed;
- removal of mooring lines and dynamic cables;
- inter-array and interconnector cables may be left in situ (other than dynamic sections); and
- decommissioning sequence will generally be the reverse of the construction sequence and involve similar types and numbers of vessels and equipment.
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