Greater Gabbard OFTO

Offshore GridOperationalGB504 MW132 kV154.27 km

Basic Information

Also known as:Greater Gabbard OFTO, Greater Gabbard offshore transmission system, Greater Gabbard offshore electricity transmission system

Status:Operational

Capacity:504 MW

Transmission Model:Developer Build & Transfer

Owners:

Equitix Fund II(33.3%)

Equitix Fund IV(66.7%)

Project Company:

Greater Gabbard OFTO plc

Type:offshore grid

Expected Life:20 years

Website:ggofto.co.uk

Description:

Greater Gabbard OFTO is the 132 kV HVAC offshore transmission system that connects the 504 MW Greater Gabbard offshore wind farm (140 turbines) in the southern North Sea to the onshore transmission network at Leiston/Sizewell, Suffolk. The transmission assets comprise two offshore substation platforms (Inner Gabbard and Galloper) linked by...

Supply Chain (0)

Project Timeline (0)

No lifecycle events recorded yet.

	North Sea	North Sea	Suffolk
Landfall	N/A	N/A	—
Grid Connection	—	—	Leiston (Sizewell) 132 kV substation

Financial

£317M€505.7M adj.€6.5k/MW-km

www.ofgem.gov.uk (Nov 2013)

CAPEX:£317M

Adjusted to 2025¹:€505.7M

Cost Intensity¹:€6.5k per MW-km

Estimate Date:Nov 2013

Source:www.ofgem.gov.uk

Notes:

OFTO transfer value / reported project capital value at financial close; covers Greater Gabbard OFTO transmission assets (two offshore substations, one onshore substation, ~3 export cables and inter-platform cable).

¹ Cost inflated in local currency then converted to euros (where applicable).

Cable Specifications

Greater Gabbard Export Cable 1

Sizewell, Suffolk, United Kingdom

1 × 132 kV HVAC · 46.09 km

System:1 × 132 kV HVAC

Route length:46.09 km(45.5 subsea · 0.59 land)

Burial depth:

Sources describe the export circuits as submarine high-voltage cables that are 'buried in the sea bed' for the offshore portion, with the submarine cable joined at landfall to a buried...

Fibre optic:

Project information states the inter-platform interconnector and subsea cables provide fibre‑optic communications for mission‑critical operational plant information (used for SCADA/operational signalling). Sources note the interconnector cable between Galloper and Inner...

Greater Gabbard Export Cable 2

Sizewell, Suffolk, United Kingdom

1 × 132 kV HVAC · 46.09 km

System:1 × 132 kV HVAC

Route length:46.09 km(45.5 subsea · 0.59 land)

Burial depth:

Described in company/regulatory documents as buried in the seabed for the offshore sections; the export cables are referred to as "three 45.5 km high voltage submarine cables buried in the...

Greater Gabbard Export Cable 3

Sizewell, Suffolk, United Kingdom

1 × 132 kV HVAC · 46.09 km

System:1 × 132 kV HVAC

Route length:46.09 km(45.5 subsea · 0.59 land)

Burial depth:

Sources state the export cables are buried in the seabed for the submarine sections; no target or actual burial-depth figures are provided. At the landfall the submarine cable is joined...

Galloper–Inner Gabbard Interconnector

1 × 132 kV HVAC · 16 km

System:1 × 132 kV HVAC

Route length:16 km(16 subsea)

Burial depth:

Sources describe this link as a submarine high-voltage cable forming an interconnector between Galloper OSP and Inner Gabbard OSP, but do not state a specific burial depth for the inter-platform...

Fibre optic:

Project materials indicate the interconnector cable provides both power transportation and fibre-optic communications for mission-critical operational plant information (SCADA/control/operational telecoms). The developer/asset manager documentation and case study state the interconnector...

Collector Stations

Inner Gabbard offshore electricity substation

Inner Gabbard (Inner Gabbard offshore electricity substation / IG-SUB), United Kingdom

504 MW 132 kV · offshore

Rating:504 MW · 132 kV

Location:offshore

Galloper offshore electricity substation (Galloper OSP)

Galloper offshore platform (Galloper OSP), North Sea, United Kingdom

132 kV · offshore

Rating:132 kV

Location:offshore

Sizewell onshore electricity substation

Sizewell onshore electricity substation (Leiston), Suffolk, UK, United Kingdom

504 MW 132 kV · onshore

Rating:504 MW · 132 kV

Location:onshore