18 Nov 2021: Update November 2021: Petrofac will install and pile the offshore sub-station jacket structure. The jacket structure will be lifted from the Heavy Transport Vessel Dongbang Giant 8 by the Heavy Lift Vessel Saipem 7000. Once in position the Saipem 7000 will upend the jacket structure and set it down on the seabed. The Saipem 7000 will then collect 12 piles from the Dongbang Giant 8 and return to the sub-station platform location. Saipem 7000 will then upend and stab the piles into the jacket pile sleeves, a hammer will then be utilised to drive the piles into position. 2 piles will be driven into each leg of the platform. On completion of pile driving the area between the piles and the pile sleeve will be filled with grout. all vessels working on the installation are expected to arrive at the Seagreen site around 18th November. Update October 2021: The offshore substation topside is expected to be installed in October 2021 (February 2021). Fabrication and delivery is expected between April 2020 and September 2021. The HLV will arrive on site and anchor, then lift the OSP onto the jacket. The topside legs will then be welded to the jacket. The installation is expected to take 8 days, followed by ~117 days commissioning. The offshore substation jacket is expected to be installed in June 2021 (February 2021). Pre-campaign surveys and seabed preparation will begin in April, with an ROV identifying boulders and orange-peel grab removing them. Installation of the jacket will see a HLV lift the jacket off supply vessel and lowered to seabed. Piles will then be inserted into pile sleeves and driven. This will then be followed by grouting and scour protection. The total installation (inc mob/demob) is expected to take 4 weeks.
United Kingdom
Under Construction
1140 MW
4C Offshore | Location Map: Lat(56.597) Lon(-1.717)

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General Information
Other Names
Zone 2, Firth of Forth Alpha-Bravo; Seagreen Alpha; Seagreen Bravo, Seagreen Phase 1
United Kingdom
Development Status
Under Construction
Category or Round
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Offshore Construction Starts
Submitted For Consent
Consent Authorised
Financial Close
First Power
Full Commissioning

Revenue Mechanism
Revenue Details
GBP 41.611/MWh (EUR 47.56/MWh)

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Power & Turbines
Windfarm Capacity
1140 MW
Turbine Model
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Other Turbine(s) Used
Min. Turbine Capacity (MW)
Max. Turbine Capacity (MW)
Min. Number of Turbines
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Max. Number of Turbines
Total Turbine Height
Hub Height
Rotor Diameter
Foundation Type
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Foundations on Wind Farm
Foundation Comments

Location & Environment
Sea Name
North Sea, Northern North Sea (Forth)
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Depth Range (Chart Datum)
Depth Range (Stated by Developer)
Distance from Shore (Developer)
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Distance from Shore (Computed)

Installation Base
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Ops and Maintenance
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Number of Offshore Platform(s)
Shared Platform Type
Grid Connection Point
Cable Landing Point

Export Cables (AC & DC)
Number of Export Cables (AC)
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Average Length per Cable (AC)
Additional Requirements (AC)
Nominal Voltage (AC)
Number of Export Cables (DC)
Average Length per Cable (DC)
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Additional Requirements (DC)
Nominal Voltage (DC)

Nominal Voltage

Onshore Cables
Number of Onshore Cables
Average Length per Cable
Expected Life