London Array OFTO
OperationalOffshore GridGB630 MW150 kV54.7 km2012
Basic information
9 fieldsAlso Known As
London Array OFTO · London Array (Phase 1) OFTO · Blue Transmission London Array · TR2 London Array OFTO
Status
operational
Capacity
630 MW
Owners
Project Company
Type
offshore grid
Transmission Model
Developer Build & Transfer
Expected Life
20 years
Website
Supply Chain (8)
Project Timeline (27)
Nov 2014Cable Repair
A free-spanning section of the London Array export cable around the BritNed cable crossing was remediated by infilling works completed in November 2014, after which no other areas of exposed export cable were reported on the route, resolving the identified integrity issue on this part of the OFTO transmission asset.
9 Apr 2014Inspection Survey
A further bathymetric post-construction survey of the London Array export cable corridors (HV1–HV4) was carried out from 9 to 16 April 2014, re-surveying the cable routes, nearshore sections and crossing areas identified as focus points in earlier work to track seabed evolution and cable exposure around the operational OFTO export system.
Sept 2013Stake Transaction
In September 2013, Blue Transmission London Array Ltd (BTLA) acquired the London Array transmission assets—including the onshore and offshore substations and four high-voltage export cables—from the project developer consortium represented by London Array Ltd, becoming the licensed Offshore Transmission Owner (OFTO) for the London Array transmission system under the UK’s offshore transmission regime.
Blue Transmission London Array Limited acquired from London Array Ltd (100%)
27 Aug 2013Inspection Survey
A post-construction bathymetric survey of the four London Array export cable corridors (HV1–HV4) was conducted from 27 August to 9 September 2013 using the survey vessel MV Wessex Explorer, mapping seabed conditions along the export routes including nearshore sections and key crossings to assess burial and seabed change around the OFTO cables.
Apr 2013Commercial Operations Full Power
Commissioning of the full 630 MW London Array offshore wind farm, including the export cable links between the offshore substations and the landfall at Seasalter and the connection into the Cleve Hill onshore substation, was completed by April 2013, indicating that the London Array OFTO transmission system had reached full operational capability for exporting power to the National Grid.
15 Feb 2013Regulatory Other
On 15 February 2013 SKM issued its final report "Review of the London Array Export Cable Costs and the Cleve Hill Incident" for Ofgem, providing an independent assessment of the London Array export cable installation costs and the additional costs associated with repair works at the Cleve Hill 400 kV onshore substation, to support Ofgem’s process of setting the final transfer value for the London Array OFTO transmission assets.
2012Cable Installation Complete
Over a 12‑month period concluding in 2012, London Array completed installation of all four export cable circuits that now comprise the London Array OFTO transmission link, with the second cable installed in early 2012 and the remaining two later that year, each approximately 54 km of 150 kV three‑core subsea cable plus short onshore sections to the Cleve Hill 400 kV substation.
2012Cable Landfall Complete
By 2012, London Array had completed landfall works for the London Array OFTO export cables at Seasalter in the Swale, including horizontal directional drilling under the Cleve Hill seawall, installation of cable ducts, pulling in and floating the cables over mudflats, trenching and backfilling in the intertidal zone, and connecting the four export circuits from the offshore substations into the onshore substation under licence conditions that governed installation windows between October 2011 and 2012.
29 Nov 2012Procurement Other
By late November 2012, Ofgem’s Transitional Round 2 tender for the London Array transmission assets had reached the stage where a Preferred Bidder had been appointed for the London Array OFTO, with the project shown in Ofgem’s "OFTO story so far" summary as having a status of "Preferred Bidder appointed" against an estimated transfer value of £428.4 million.
Oct 2012First Power
After the export cables were connected at the Cleve Hill onshore substation, enabling transfer of power to the National Grid, the London Array transmission system (onshore and offshore substations and four high-voltage export cables) carried first power in October 2012 when the first turbine of the London Array offshore wind farm began operation.