London Array OFTO

Offshore GridOperationalGB630 MW150 kV219.08 km

Basic Information

Also known as:London Array OFTO, London Array (Phase 1) OFTO, Blue Transmission London Array, TR2 London Array OFTO

Status:Operational

Capacity:630 MW

Transmission Model:Developer Build & Transfer

Owners:

DTUK BLK Bidco Holdings Limited (ultimate controller BlackRock)(50%)

Alba Infra Founding Partners SAS(50%)

Project Company:

Blue Transmission London Array Limited

Type:offshore grid

Expected Life:20 years

Website:www.bluetransmission.com

Description:

The London Array OFTO is the high-voltage AC transmission link that conveys power from the London Array Phase 1 offshore wind farm (630 MW) in the Outer Thames Estuary to the onshore transmission network at the Cleve Hill 400 kV substation in north Kent. The connection comprises two manned offshore...

Supply Chain (0)

Project Timeline (0)

No lifecycle events recorded yet.

	Outer Thames Estuary	Outer Thames Estuary	Kent
Landfall	N/A	N/A	—
Grid Connection	—	—	Cleve Hill 400 kV substation (National Grid)

Financial

£458.904M€732M adj.€5.3k/MW-km

www.ofgem.gov.uk (Sept 2013)

CAPEX:£458.904M

Adjusted to 2025¹:€732M

Cost Intensity¹:€5.3k per MW-km

Estimate Date:Sept 2013

Source:www.ofgem.gov.uk

Notes:

Final Ofgem transfer value for the London Array OFTO transmission assets (transfer to Blue Transmission London Array Ltd). Covers two offshore platforms, four ~54 km export cables, short onshore section...

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

Cable Specifications

Export Cable 1 (London Array)

Graveney, Kent, United Kingdom

1 × 150 kV HVAC · copper 630 mm² · 157.5 MVA · 54.77 km

System:1 × 150 kV HVAC

Construction:copper · 630 mm²

Power rating:157.5 MVA

Route length:54.77 km(54 subsea · 0.77 land)

Burial depth:

Export cables are installed subsea for the ~50–54 km route from the offshore substations to the Cleve Hill landfall and are routed into a jointing pit and onshore ducts at...

Fibre optic:

The London Array export cables include fibre‑optic cores. Developer documentation states that, like the array cables, the export cables contain fibre optic cores used for remote monitoring and control of...

Export Cable 2 (London Array)

Graveney, Kent, United Kingdom

1 × 150 kV HVAC · copper 630 mm² · 54.77 km

System:1 × 150 kV HVAC

Construction:copper · 630 mm²

Route length:54.77 km(54 subsea · 0.77 land)

Burial depth:

The export cables are installed buried in the seabed where feasible and transition to shore via protective J-tubes and a jointing pit at Cleve Hill. Project documentation notes array/collector cables...

Fibre optic:

The London Array export cables (Nexans-manufactured HV export circuits) include fibre optic cores. Documentation states the export cables "contain fibre optic cores" similar to the array cables, and these cores...

Export Cable 3 (London Array)

Graveney, Kent, United Kingdom

1 × 150 kV HVAC · copper 630 mm² · 54.77 km

System:1 × 150 kV HVAC

Construction:copper · 630 mm²

Route length:54.77 km(54 subsea · 0.77 land)

Burial depth:

Export cables were installed buried in the seabed where feasible, with onshore sections routed underground into the Cleve Hill substation. Post‑construction monitoring identified local seabed erosion/scour along sections of the...

Fibre optic:

The London Array export cables incorporate fibre‑optic cores. Project documentation states the export cables, like the array cables, contain fibre optic cores used to allow remote monitoring and control (operational...

Export Cable 4 (London Array)

Graveney, Kent, United Kingdom

3 × 150 kV HVAC · copper 630 mm² · 54.77 km

System:3 × 150 kV HVAC

Construction:copper · 630 mm²

Route length:54.77 km(54 subsea · 0.77 land)

Burial depth:

Export cables run subsea for ~54 km and transition ashore through the Cleve Hill sea wall into a jointing pit. Post-construction surveys and monitoring reported seabed erosion/scour along sections of...

Fibre optic:

The export cables include fibre-optic cores to support turbine/substation monitoring and control; the project documentation states the export cables contain fibre optic cores but does not specify the number of...