The Hornsea Four Offshore Wind Farm Order 2023

Design parameters E+W+S

1.—(1) The total number of offshore electrical installations must not exceed nine, and consisting of a combination of no more than—

(a) six small offshore transformer substations;

(b) three large offshore transformer substations;

(c) three offshore HVAC booster stations;

(d) six small offshore HVDC converter substations; and

(e) three large offshore HVDC converter substations.

(2) The dimensions of any small offshore transformer substations (including auxiliary structures, but excluding masts, radar and antennae) forming part of the authorised scheme must not exceed—

(a) 100 metres in height when measured from LAT;

(b) 90 metres in length; and

(c) 90 metres in width.

(3) The dimensions of any large offshore transformer substations (including auxiliary structures, such as a helipad, crane, lightning protection, but excluding masts, radar and antennae) forming part of the authorised scheme must not exceed—

(a) 100 metres in height when measured from LAT;

(b) 180 metres in length; and

(c) 90 metres in width.

(4) The dimensions of any offshore HVAC booster station (including auxiliary structures, such as a helipad, crane, lightning protection, but excluding masts, radar and antennae) forming part of the authorised scheme must not exceed—

(a) 100 metres in height when measured from LAT;

(b) 90 metres in length; and

(c) 90 metres in width.

(5) The dimensions of any small offshore HVDC converter substations (including auxiliary structures, such as a helipad, crane, lightning protection, but excluding masts, radar and antennae) forming part of the authorised scheme must not exceed—

(a) 90 metres in height when measured from LAT;

(b) 100 metres in length; and

(c) 100 metres in width.

(6) The dimensions of any large offshore HVDC converter substations (including auxiliary structures, such as a helipad, crane, lightning protection, but excluding masts, radar and antennae) forming part of the authorised scheme must not exceed—

(a) 100 metres in height when measured from LAT;

(b) 180 metres in length; and

(c) 90 metres in width.

(7) Offshore electrical installation foundation structures forming part of the authorised scheme must be one of the following foundation options—

(a) for small offshore transformer substations and offshore HVAC booster stations either monopile foundations, mono suction bucket foundations, gravity base structures, jacket foundations or box–type gravity base structures; and

(b) for large offshore transformer substations and offshore HVDC converter stations either monopile foundations, mono suction bucket foundations, jacket foundations, box–type gravity base structures, gravity base structures, pontoon gravity base type 1 structures, or pontoon gravity base type 2 structures.

(8) No offshore electrical installation—

(a) jacket foundation employing pin piles forming part of the authorised scheme may—

(i) have a pin pile diameter of greater than four metres; and

(ii) employ more than 16 pin piles per jacket foundation; and

(b) monopile foundation forming part of the authorised scheme may have a diameter greater than 15 metres.

(9) The total seabed footprint area for offshore electrical installation foundations must not exceed—

(a) 101,250 square metres excluding scour protection; and

(b) 371,250 square metres including scour protection.

(10) The area of scour protection material for offshore electrical installation foundations must not exceed 270,000 square metres.

(11) The total number of cable crossings when combined with the deemed marine licence granted under Schedule 11 of the Order must not exceed 86, unless otherwise agreed in writing between the undertaker and the MMO.

(12) The total number of gravity base structures must not exceed ten for offshore electrical installations, or nine where the offshore accommodation platform authorised by the deemed marine licence granted under Schedule 11 of the Order utilises a gravity base structure.

(13) The offshore electrical installations comprised in the authorised scheme must be constructed in accordance with the parameters set out in the pro–rata annex.

(14) A bridge link forming part of the authorised scheme must be installed at a minimum height of 20 metres when measured from LAT.

Commencement Information

I1 Sch. 12 Pt. 2 para. 1 in force at 3.8.2023, see art. 1