Appendix 1A: Array HRA Stage One LSE2 Screening Report

  1. Please find appendix 1A attached to this document separately.

 

[1] Recognising the potential for non-significant effects to accumulate or act in-combination.

[2] Minimum distance measured from rotors of one wind turbine to the rotors of another wind turbine.

[3] Maximum distance measured from rotors of one wind turbine to the rotors of another wind turbine.

[4] The extent to which a floating foundation may offset from its design coordinate (to be confirmed at final design) is dependent upon the magnitude of wind, sea, swell and current conditions. This parameter assumes the floating foundation under normal operation in the most extreme conditions that the mooring system is designed for.

[5] Mooring line radius is measured from top connector (at floating foundation) to bottom connector- (at touchdown point) in static conditions.

[6] Based upon a maximum number of anchors across the Array of 1,590 (maximum number of foundation substructures of 265 multiplied by six anchors per foundation). The proportion of driven piles and suction anchors for Option 4 is 65% and 35%, respectively, equalling 1,033.5 driven piles and 556.5 suction anchors. Please note, that when this decimal is rounded up (as in Table 4.8   Open ▸ ) this totals a maximum of 1,591 anchors, however, the maximum number of anchors installed across the Array will not exceed 1,590, nor the parameters presented within Table 4.8   Open ▸ .

[7] Anchoring Option 2 (DEAs only) does not require scour protection, therefore, this option has been omitted from this table.

[8] Based upon findings of the Ordtek (2022) desk-based study. This value is based upon German World War II ground mines; these have not been recorded as having been present within the vicinity of the Array, however, there is a background risk from unrecorded mine lays. The likelihood of encountering a UXO of this type and charge weight is considered very unlikely as these types of mines typically targeted ports and shallower waters than are recorded within the Array (Ordtek, 2022).

[9] Based upon findings of the Ordtek (2022) desk-based study. This value is based upon British World War II mines; a total of nine British World War II minefields are recorded as having been present within the vicinity of the Array, the closest of which was recorded as being located 23 km north of the Array. Although mine sweeping operations were undertaken within the vicinity, there is potential for migration and subsequent burial of UXO from their original lay position, therefore, there is potential that these may be encountered within the Array although this is considered unlikely (Ordtek, 2022).

[10] Based upon Anchoring Option 1 (driven piles only) for 265 foundations.

[11] Based upon Anchoring Option 1 (driven piles only) for 265 foundations with minimum drilling rate of 0.2 m per hour.

[12] Based upon Anchoring Option 1 (driven piles only) for 265 foundations.

[13] Based upon Anchoring Option 5 (Driven piles only, shared anchoring between floating foundations) for 265 foundations.

[14] Based upon Anchoring Option 5 (Driven piles only, shared anchoring between floating foundations) for 265 foundations.

[15] Based upon the minimum drilling rate of 0.2 m per hour.