Paragraph 4 Foundation methodsI1

England, Wales and Scotland

(1)

The undertaker must in fixing to the seabed any structures comprised in Works Nos. 1, 2, 3, 4 and 5 use one of the following methods—

(a)

monopile foundations;

(b)

jacket foundations supported by piles; or

(c)

gravity base foundations.

(2)

The undertaker must not use the monopile foundation method or any other method which includes braced monopiles to fix to the seabed any offshore HVDC converter station.

(3)

The following parameters apply in respect of the foundation methods used to fix wind turbine generators to the seabed—

(a)

where monopile foundations are used—

(i)

the area occupied by the foundations and the scour protection for each individual structure must not exceed 1,419 m²;

(ii)

the diameter of each foundation must not exceed 8.5 metres;

(b)

where jacket foundations (driven/drilled piles) are used—

(i)

the area occupied by the foundations and the scour protection for each individual structure must not exceed 707 m² per wind turbine;

(ii)

the number of piles per jacket must not exceed four;

(iii)

the diameter of each pile must not exceed three metres;

(c)

where jacket foundations (suction piles) are used—

(i)

the area occupied by the foundations and scour protection for each individual structure must not exceed 6,362 m²;

(ii)

the number of piles per jacket must not exceed four;

(iii)

the diameter of each pile must not exceed 15 metres;

(d)

where gravity base foundations are used—

(i)

the area occupied by the foundations and the scour protection for each individual structure must not exceed 6,362 m²;

(ii)

the seabed levelling diameter must not exceed 70 metres;

(iii)

the cone diameter must not exceed 50 metres at its base.

(4)

The following parameters apply in respect of the foundation methods used to fix offshore accommodation platforms to the seabed—

(a)

where monopile foundations are used—

(i)

the area occupied by the foundations and the scour protection for each individual structure must not exceed 1,419 m²;

(ii)

the diameter of each foundation must not exceed 8.5 metres;

(b)

where jacket foundations (driven/drilled piles) are used—

(i)

the area occupied by the foundations and the scour protection for each individual structure must not exceed 1,414 m²;

(ii)

the number of piles must not exceed eight;

(iii)

the diameter of each pile must not exceed three metres;

(c)

where jacket foundations (suction piles) are used—

(i)

the area occupied by the foundations and the scour protection for each individual structure must not exceed 6,362 m²;

(ii)

the number of piles per jacket must not exceed eight;

(iii)

the diameter of each pile must not exceed 15 metres;

(d)

where gravity base foundations are used—

(i)

the area occupied by the foundations and the scour protection for each individual structure must not exceed 6,362 m²;

(ii)

the seabed levelling diameter must not exceed 70 metres;

(iii)

the cone diameter must not exceed 50 metres at its base.

(5)

The following parameters apply in respect of the foundation methods used to fix offshore HVAC collector substations to the seabed—

(a)

where monopile foundations are used—

(i)

the area occupied by the foundations and the scour protection for each individual structure must not exceed 1,419 m²;

(ii)

the diameter of each foundation must not exceed 8.5 metres;

(b)

where jacket foundations (driven/drilled piles) are used—

(i)

the area occupied by the foundations and the scour protection for each individual structure must not exceed 1,924 m²;

(ii)

the number of piles per jacket must not exceed eight;

(iii)

the diameter of each pile must not exceed 3.5 metres;

(c)

where jacket foundations (suction piles) are used—

(i)

the area occupied by the foundations and the scour protection for each individual structure must not exceed 12,723 m²;

(ii)

the number of piles per jacket must not exceed eight;

(iii)

the diameter of each pile must not exceed 15 metres;

(d)

where gravity base foundations are used—

(i)

the area occupied by the foundations and the scour protection for each individual structure must not exceed 6,362 m²;

(ii)

the seabed levelling diameter must not exceed 70 metres;

(iii)

the cone diameter must not exceed 50 metres at its base.

(6)

The following parameters apply in respect of the foundation methods used to fix offshore HVDC converter stations to the seabed—

(a)

where jacket foundations (driven/drilled piles) are used—

(i)

the area occupied by the foundations and the scour protection for each individual structure must not exceed 4,330 m²;

(ii)

the number of piles per jacket must not exceed 18;

(iii)

the diameter of each pile must not exceed 3.5 metres;

(b)

where jacket foundations (suction piles) are used—

(i)

the area occupied by the foundations and the scour protection for each individual structure must not exceed 12,723 m²;

(ii)

the number of piles per jacket must not exceed eight;

(iii)

the diameter of each pile must not exceed 15 metres;

(c)

where gravity base foundations are used—

(i)

the area occupied by the foundations and the scour protection for each individual structure must not exceed 19,500 m²;

(ii)

the number of pontoons for each individual structure must not exceed two;

(iii)

the pontoons must not exceed 110 metres in length or 35 metres in width.

(7)

The following parameters apply in respect of the foundation methods used to fix the offshore reactive compensation substation to the seabed—

(a)

where monopile foundations are used—

(i)

the area occupied by the foundations and the scour protection must not exceed 1,419 m²;

(ii)

the diameter of each foundation must not exceed 8.5 metres;

(b)

where jacket foundations (driven/drilled piles) are used—

(i)

the area occupied by the foundations and the scour protection must not exceed 1,414 m²;

(ii)

the number of piles per jacket must not exceed eight;

(iii)

the diameter of each pile must not exceed three metres;

(c)

where jacket foundations (suction piles) are used—

(i)

the area occupied by the foundations and the scour protection must not exceed 6,362 m²;

(ii)

the number of piles per jacket must not exceed eight;

(iii)

the diameter of each pile must not exceed 15 metres;

(d)

where gravity base foundations are used—

(i)

the area occupied by the foundations and the scour protection for each individual structure must not exceed 6,362 m²;

(ii)

the seabed levelling diameter must not exceed 70 metres;

(iii)

the cone diameter must not exceed 50 metres at its base.

(8)

The combined total volume of scour protection for the wind turbine generators and the offshore accommodation platforms forming part of the authorised development must not exceed 3,226,187 m³.

Annotations

Commencement

I1: Sch. 1 Pt. 3 para. 4 in force at 31.12.2014, see art. 1