Westermost Rough
Located 8km NE of Withernsea off Holderness coast, Yorkshire. Pioneered Siemens 6MW offshore turbine.
Status
Operationallifecycle stage
Ownership
Ørsted — 50% ◆AIArjun Infrastructure Partners — 25% ◆
Equitix — 12.5% ◆USUniversities Superannuation Scheme — 9.37% ◆
STStepStone Group — 3.13% ◆
Location
United KingdomNorth Sea
Technology
Capacity
210 MW ◆
Turbines
35 × 6 MW ◆
Model
Siemens Swt 6-0-154 ◆
Foundation
Monopile ◆
Site & conditions
Site rights
Seabed rights held ∴
Origination
Crown Estate Round 2 · 2003 ·
Water depth
15–15 m ◆
Distance from shore
8 km ◆
Wind speed
9.5 m/s @ 100 m ≈
Revenue & grid
Offtake
Other ◆
Grid
Secured · 2015 ◆
Connection
Hedon substation, Yorkshire (275kV) ◆
Schedule
FID
Jan 2013 ◆
COD
Jul 2015 ◆
Project timeline & ownership verified milestones on the spine · ownership from Hafrok’s transactions record
Origination · 2003-12
Crown Estate Round 2
- Awarded to
- Ørsted
- Basis
- seabed award
From the auction results — the round that created the project.
Farmdown · 2014-03
Ørsted → Marubeni / Green Investment Group 50%
- Stake
- 50%
- Consideration
- €286m
- Implied 100% value
- €572m
- Implied
- €2.73m / MW
- Basis
- Equity plus construction commitment
- Announced
- 2014-03
- Closed
- 2014-04-04
- Project stage
- under construction
DONG Energy (now Ørsted) sold 50% of Westermost Rough, through its holding company Westermost Rough (Holding) Limited, to WMR JV Investco, the vehicle of Marubeni (25%) and the UK Green Investment Bank (25%). Signed 31 March 2014, completed 4 April 2014. The buyer's accounts put the consideration at GBP 238.0m: GBP 148m invested in the construction of the wind farm, GBP 44.7m paid upfront and GBP 45.7m deferred. DONG had announced about GBP 240m. The farm began commercial operation on 29 June 2015; its export cables were sold to the OFTO in February 2016. EUR figures at the ECB 2014-03 monthly average.
Evidence
- offshoreWIND.biz — Marubeni, UK GIB Acquire Half of Westermost Rough OWF ↗ 2014-03 ◆ held
- DONG Energy (Ørsted) — DONG Energy divests 50% of Westermost Rough to Marubeni and UK Green Investment Bank ↗ 2014-03-31 ◆ held
- Companies House — Westermost Rough Limited - accounts to 31 December 2013 ↗ 2014-03-10 ◆ held
- Companies House — Westermost Rough Limited - accounts to 31 December 2014 ↗ 2015-05-26 ◆ held
- Companies House — Westermost Rough Limited - accounts to 31 December 2015 ↗ 2016-05-31 ◆ held
- Companies House — Westermost Rough (Holding) Limited - accounts to 31 December 2014 ↗ 2015-06-30 ◆ held
- Companies House — WMR JV Investco Limited - accounts to 31 March 2015 ↗ 2015-11-20 ◆ held
- Ofgem — Offshore Transmission: Cost Assessment for the Westermost Rough project ↗ 2016-02 ◆ held
- DONG Energy — DONG Energy - Interim financial report Q1 2014 ↗ 2014-04 ◆ held
From Hafrok’s transactions record
Corporate · 2017-04-20
Green Investment Group (UK Government) → Macquarie Group / MEIF5 / Universities Superannuation Scheme 25%
- Stake
- 25%
- Consideration
- not disclosed
- Announced
- 2017-04-20
- Closed
- 2017-08
- Project stage
- operational
The farm's 25% changed hands because its holder, the UK Green Investment Bank, was itself sold: the UK Government sold the whole bank to a consortium of Macquarie Group, Macquarie European Infrastructure Fund 5 and the Universities Superannuation Scheme (agreed 20 April 2017, completed August 2017). The bank's offshore wind stakes went into a new offshore wind vehicle in which USS and MEIF5 invested and the bank stayed an investor. The price was paid for the whole bank; none was published for this farm.
Evidence
- Macquarie Group — Macquarie-led consortium to acquire the Green Investment Bank ↗ 2017-04-20 ◆ held
- Ørsted A/S — Full power at Westermost Rough offshore wind farm ↗ 2015-05 ◆ held
From Hafrok’s transactions record
Secondary trade · 2018-03
Marubeni → Green Investment Group 25%
- Stake
- 25%
- Consideration
- not disclosed
- Announced
- 2018-03
- Closed
- 2018-Q2
- Project stage
- operational
Green Investment Group (Macquarie) acquired Marubeni Corporation's 25% stake. GIG joined a consortium with MEIF5 and Universities Superannuation Scheme (USS) that already held a 25% stake. Consideration not publicly disclosed. After deal: Ørsted 50%, GIG/MEIF5/USS consortium 50%.
Evidence
From Hafrok’s transactions record
Secondary trade · 2023-04
Green Investment Group (Offshore Wind Company — MEIF5's 50% LP interest) → Equitix 12.5%
- Stake
- 12.5%
- Consideration
- not disclosed
- Announced
- 2023-04
- Closed
- 2023-Q3
- Project stage
- operational
Part of Macquarie's sale of MEIF5's 50% stake in Offshore Wind Company to Equitix. Same portfolio transaction as Sheringham Shoal, Lincs, Rhyl Flats.
Evidence
- macquarie.com — Macquarie Asset Management to divest stakes in eight UK offshore wind farms ↗ 2023-04 ◆ held
From Hafrok’s transactions record
Dashed tick marks today (13 Oct 2026). The teal diamond on the spine is origination — the seabed award or round that created the project. Every other ownership event lives in the band below: one station per recorded deal, dated at its label, in deal order rather than to calendar scale. Secondary trades appear only at the interchanges; grey lines are parties whose entry or exit Hafrok’s record does not hold.
Announced-COD history: 2015-Q2→2015-07 · 2 recorded revisions · held within the year (first announced 2015-Q2, latest 2015-07)
Revenue & offtake the regime the project was built under
Offtake regime: ROC 2.0 ROCs/MWh (subsidy expiry 2035)
A built project sells its power under the contract or support regime it was financed with; it is not expected to bid into new government offtake rounds. Where the record does not yet name that regime, the row says so rather than guessing.
Installation how the build is going · from sourced statements and Hafrok’s registers
Installation complete
Installation · on record
StageOperational
In operation since2015-07
Offshore construction2014-02 → 2015-07
Construction ports
PortGrimsby Royal Dock (O&M base) ◆operations maintenance
PortGrimsby Fish Dock (construction management) ◆construction management
Grid connection
from Hafrok’s substation, converter and cable registers
Offshore platforms · 1
Offshore substationWestermost Rough Offshore Substation·150/33 kV · in service 2015 · owner TC Westermost Rough OFTO Limited (Transmission Capital Partners LP / International Public Partnerships)
Grid connection · ready in time?
when each part of the grid connection is due, against the start date the developer states (black line) · a bar spans the whole year, quarter or month the source gives
installed or in serviceexpected deliveryearlier date that was later moved
Sources & verification
Rests on 15 sources (14 primary) · ◆ 8 documents held
◆Verified≈Modelled◇Sourced∴Inferred⌁Convention○Unverified∅No source·Derived
Numbers are stable citation ids — grouped by source class, so they are not consecutive.
Regulator1
[19]
Department for Energy Security and Net Zero2026-05-06◆ Renewable Energy Planning Database (REPD…
“REPD Q1 2026 quarterly extract — Ref ID 2545: Site Name "Westermost Rough A", Development Status "Operational", Installed Capacity 210 MWelec, Operator "Orsted (formerly Dong Energy)"”
supportsRegister entry
Operator6
[1]
Ørsted A/S (then DONG Energy)2014-08-14◆ First 6MW turbine erected at DONG Energy…
“The first of 35 Siemens 6MW turbines has been successfully erected at the Westermost Rough offshore wind farm, a joint venture between DONG Energy (50%) and its partners Marubeni Corporation (25%) and…”
supportsTurbinesModelUnit capacityTotal capacityconstruction management
[2]
Ørsted A/S (then DONG Energy)2014-09-08◆ First power at DONG Energys Westermost R…
“2014-09-08T06:17:00.0000000Z — Electricity has been generated for the first time at Westermost Rough Offshore wind farm off the UK's East Coast, a joint venture between DONG Energy (50%) and its partn…”
supportsFirst power
[4]
Ørsted A/S (then DONG Energy)2015-05-26◆ Full power at Westermost Rough offshore …
“2015-05-26T09:00:00.0000000Z — Full power output has been achieved at the Westermost Rough offshore wind, a major renewable energy project located off the UK's east coast. Westermost Rough is located …”
supportsCommercial operationDistance from shoreCoordinates
[5]
Ørsted A/S (then DONG Energy)2015-07-01◆ Ground breaking Westermost Rough offshor…
"2015-07-01T10:30:00.0000000Z — Westermost Rough – the first offshore wind farm in the world to make commercial use of giant Siemens 6MW turbines with 75 metre blades – has been officially opened at a…
supportsCommercial operationCOD historyFoundationStatusConnection point+1 more
[7]
Ørsted A/S (then DONG Energy)2017-03-21◆ Good Energy sources wind power from DONG…
“The deal secures 12% of the output of the 210MW Westermost Rough Offshore Wind Farm operated by DONG Energy in the North Sea, enough renewable electricity to power more than 26,000 average homes. West…”
supportsMechanismDetail
[20]
National Energy System Operator (NESO)2026-07-21◆ NESO Transmission Entry Capacity (TEC) R…
“NESO TEC Register, edition 21 July 2026 - PRO-000223: "Westermost Rough Offshore Wind Farm", Status "Built", MW Connected 206.5, Effective From n/a, Customer "WESTERMOST ROUGH LIMITED"”
supportsRegister entry
Trade press8
[9]
Ørsted A/S (then DONG Energy) via GlobeNewswire2013-01-30
“DONG Energy has decided to build the offshore wind farm Westermost Rough in the North Sea on the British east coast. Offshore construction of the Westermost Rough offshore wind farm will begin in firs…”
supportsFinal investment decision
[10]
[14]
[15]
Transmission Investment
“The assets connect the 210MW Westermost Rough offshore windfarm to the 275kV electricity transmission network at Hedon substation in Yorkshire.”
supportsStatusConnection point
[16]
Power Technology2025
Press report — cited, not quoted; read it at the source link.
supportsoperatorinvestor
[17]
Power Technology (GlobalData)2015-07-23
Press report — cited, not quoted; read it at the source link.
supportsConsentConsent granted
[18]
[21]
Ørsted2025-Q2◆ Orsted — orsted factsheet asset book q2 …
“Westermost Rough (35 x SWT-6.0-154) | Arjun Infrastructure, USS, Equitix, Macquaire | 210 | 210 | 105 | Pro rata | 0.5 | 0.5 | 2015 | ROC | 2035 | - | 2”
supportsMechanismDetail