Hornsea Wind Farm

The tendering process for Round 3 offshore wind farm opportunities was begun by the Crown Estate in 2008. Bids were received in March 2009, and Zone Development Agreements signed in December 2009.{{sfn|Crown Estate|2010|loc=§1.1}} The Hornsea development zone was awarded to a joint venture (SMart Wind) of Siemens and a consortium Mainstream Renewable Power including Hochtief. The development had an estimated potential generating capacity of 4 GW.

The Hornsea site is one of three off the British coast in the North Sea, roughly halfway between the other two: Dogger Bank Wind Farm and East Anglia Wind Farm.{{sfn|Crown Estate|2013|p=10}} The Hornsea site ('Zone 4', also known as 'Holderness' zone) has a total area of {{convert|4730|km2}}, and is {{convert|38|km}} from land at the closest point; water depth in the zone is from {{convert|22|to|73|m}}, with a tidal range of {{convert|2|to|5|m}}, and typical annual wave height of {{convert|1.35|to|1.78|m}}. The surface of the seabed consists primarily of sands and gravel.{{sfn|ABP mer|2009|loc=§6}}

In 2011 the Danish firm Ørsted A/S (then named DONG Energy) became a partner in SMart Wind. In early 2015 Ørsted A/S became the 100% owner of the first phase, Project 1, of the scheme. Ørsted acquired rights to the remaining subzones of the Hornsea development (2 & 3) by August 2015.

In 2016 Ørsted reached an agreement with the Crown Estate for amended plans for the Hornsea Two and Hornsea Three phases. Hornsea Three was split into two new projects, Hornsea Three and Hornsea Four; the new phases were expected to be developed in the 2020s.{{cite press release| url = http://www.thecrownestate.co.uk/news-and-media/news/2016/uks-offshore-wind-project-pipeline-further-strengthened/| title = UK's offshore wind project pipeline further strengthened| date = 8 March 2016|work = www.thecrownestate.co.uk| access-date = 8 March 2016}} The changes increased the potential generating capacity of the wind farm to 6 GW, with Hornsea Three estimated at 1–2 GW and Hornsea Four at about 1 GW.{{cite web| url = http://renews.biz/101835/dong-eyes-2gw-hornsea-bonus| title = Dong eyes 2GW Hornsea bonus | work = renews.biz | access-date = 8 March 2016}}{{cite press release| date = 8 March 2016| url = http://www.dongenergy.co.uk/news/press-releases/articles/dong-energy-reaches-agreement-with-the-crown-estate-for-hornsea-zone| title = DONG Energy reaches agreement with The Crown Estate for Hornsea zone | publisher = Dong Energy | access-date = 8 March 2016}}

The initial scoping report for "Project One" within the Hornsea zone identified it as a subzone of {{convert|629.6|km2}} in the centre of the Hornsea zone, with an estimated potential wind farm of 1.2 GW, divided into two further subzones of 600 MW capacity each. The zone was to connect to an existing 400 kV National Grid substation at Killingholme.{{sfn|SMart Wind|2010|loc = §1.1–1.4}} A variety of configurations were considered – foundations of pile jacket, monopile or gravity base; turbines from 3.6 to 8 MW rated power; with electrical power export by HVDC.{{sfn|SMart Wind|2010|loc = §3.29–3.55}} Later DONG Energy added the consideration to use HVAC export cables.{{sfn|SMart Wind|2012|loc = §1.2}} The chosen cable export was planned to make landfall at Horseshoe Point (northeast of Marshchapel, East Lindsey), then passing {{convert|40|km}} west and northwest to a substation near Killingholme Power Station, North Killingholme in North Lincolnshire.{{sfn|SMart Wind|2013|loc = §5.1.5–5.1.8, Fig 5.1}}

Within the zone of Project 1 the primary underlying geology consisted of deposits from the Quaternary Period consisting of Bolders bank, Botney Cut and Eem formations – primarily sediments or tills – gravelley/sandy clays, overlying sediments were sands or gravels up to {{convert|2|to|3|m}} thick, with waves within the area varying in height by {{convert|1|to|3|m}}. Project 1 water depths were generally {{convert|25|to|30|m}}.{{sfn|SMart Wind|2010|loc = §5.2–5.14, §5.15–5.18}}

In 2011 Smart Wind signed lease agreements with the Crown Estate for "Heron Wind" and "Njord" areas making up the zone. The zone was given provisional Contracts for Difference (CfD) renewable subsidies by the UK government in April 2014. Hornsea Project 1 was given planning consent in December 2014. The CfD strike price was £140 per MWh (in 2012 prices).{{cite web| url = http://ec.europa.eu/competition/state_aid/cases/253211/253211_1583612_84_2.pdf | title = State aid SA.38758 (2014/N), SA.38759 (2014/N), SA.38761 (2014/N), SA.38763 (2014/N) & SA.38812 (2014/N) – United Kingdom – Support for five Offshore Wind Farms: Walney, Dudgeon, Hornsea, Burbo Bank and Beatrice| publisher = European Commission| date = 23 July 2014| at = Table 2, pp.4–5 |access-date=3 February 2016}} In early 2015 DONG acquired all of the project, becoming 100% owner.

Seabed investigation including boreholes at turbine foundation positions was completed by Fugro by April 2015. In mid 2015 DONG selected Siemens Wind Power 7 MW turbines with {{convert|154|m}} rotor turbines for the project – around 171 turbines would be used for the wind farm. In its 2015 financial report DONG stated it had chosen to use suction bucket foundations on a third of the turbines at Hornsea.{{cite web| url =https://assets.dongenergy.com/DONGEnergyDocuments/com/Investor/Financial_Presentations/fy15_result_presentation.pdf| title = Financial report full year 2015 – Investor Presentation| date = 4 February 2016| publisher =DONG Energy| page=6|access-date=16 February 2016}} The rationale for use of the new foundation type is thought to be a simplified foundation installation, requiring only a heavy-lift crane to lower the foundation to the sea bed, reducing costs.{{cite web| url = http://ing.dk/artikel/nyt-havmoellefundament-skal-staa-sin-proeve-i-gigantisk-havmoellepark-182016| title =Nyt havmøllefundament skal stå sin prøve i gigantisk havmøllepark| date = 5 February 2016| work = ing.dk| language = da|trans-title=New offshore wind foundation to be tested at giant offshore wind farm |access-date=5 February 2016}}{{refn|group="note"|Suction bucket with jacket foundations were tested at Borkum Riffgrund.}}

DONG Energy formally committed to building the wind farm in early 2016. The expected completion date for the project was 2020.{{cite web| url =http://renews.biz/101385/dong-commits-to-hornsea-build| title = Dong commits to Hornsea build| date = 3 February 2016| work = renews.biz |access-date=3 February 2016}}{{cite press release | url=https://www.gov.uk/government/news/worlds-largest-offshore-wind-farm-to-be-built-in-the-uk| title = World's largest offshore wind farm to be built in the UK| date = 3 February 2016| publisher = Department of Energy and Climate Change|access-date=3 February 2016}} A £25 million contract to construct the onshore substation at North Killingholme had been awarded to Balfour Beatty in late 2015.

NKT Cables and ABB were awarded €139 (c. $158) million and $250 million contracts to supply 220 kV AC export cables in March/April 2016.{{cite web| url = http://renews.biz/102112/abb-wins-hornsea-gem | title = ABB wins Hornsea gem | date = 31 March 2016| work = renews.biz| access-date = 31 March 2016}}{{cite web| url = http://renews.biz/102171/nkt-to-help-wire-hornsea-1| title = NKT to help wire Hornsea 1| date = 5 April 2016 | work = renews.biz | access-date = 5 April 2016}} In late 2016 JDR Cables was contracted to supply {{convert|242|km}} of inter-array subsea power cables for the wind farm;{{cite web| url = http://www.offshorewind.biz/2016/11/01/jdr-strikes-gold-with-hornsea-project-one-contract/| title = JDR Strikes Gold with Hornsea Project One Contract| date = 1 November 2016| work = www.offshorewind.biz | access-date = 1 November 2016}} Nexans was awarded a contract for {{convert|139|km}} of inter-array cables;{{cite web| url = http://renews.biz/105264/nexans-nails-hornsea-1-wire-job/| title = Nexans nails Hornsea 1 wire job| date =14 December 2016| work = renews.biz|access-date=5 January 2017}} and EEW was awarded a contract to supply 116 monopiles.{{cite web|url =http://renews.biz/105046/eew-secures-hornsea-prize/| title = EEW secures Hornsea prize| date = 25 November 2016| work = renews.biz |access-date=5 January 2017}}

Bladt Industries/Offshore Structures (Britain) Ltd. was awarded a contract for 96 tower transition pieces in early 2017, to be constructed at Aalborg, Denmark and Billingham, UK.{{cite web| url = http://renews.biz/105441/bladt-osb-secure-hornsea-prize/| title = Bladt, OSB secure Hornsea prize| date = 5 January 2017| work = renews.biz |access-date=5 January 2017}} Dragados Offshore was awarded in early 2016, a contract for construction of four jacket type foundations for the AC platforms at its yard in Cádiz, Spain.{{cn|date=June 2023}}

Construction of the onshore cable route was begun in late 2016 under J. Murphy & Sons.{{cite web| url = http://renews.biz/104796/hornsea-1-starts-onshore-links/| title = Hornsea 1 starts onshore links| date = 3 November 2016|work = renews.biz | access-date = 3 November 2016}}

The wind farm was scheduled to be constructed between 2018 and 2020, and expected to provide an annual production of around 4.1 terawatt-hours (TWh).

The first foundation of the new windpark was installed by DEME Group's subsidiary GeoSea in January 2018.{{cite web| url = https://orsted.co.uk/Media/Newsroom/News/2018/01/Orsted-begins-offshore-construction-for-Hornsea-Project-One | title = Ørsted begins offshore construction for Hornsea Project One | date = 26 January 2018 | work = orsted.co.uk |access-date = 31 January 2018}}

The export cables were installed by Tideway Offshore Solutions, a subsidiary company of the Belgian DEME Group. The installation was completed in December 2018, several months ahead of schedule.{{cite web|url=https://www.oedigital.com/news/460636-hornsea-one-export-cable-installation-completed |title=Hornsea One Export Cable Installation Completed|date=11 December 2018|website=Offshore Engineer Magazine|access-date=12 February 2019}}

Hornsea 1 began supplying power to the UK national electricity grid in February 2019,{{cite web|url=https://www.theguardian.com/environment/2019/feb/11/biggest-offshore-windfarm-to-start-uk-supply-this-week |title=Biggest offshore windfarm to start UK supply this week|first=Adam|last=Vaughan|date=11 February 2019|newspaper=The Guardian|access-date=12 February 2019}}{{cite news |title=First power from world's biggest wind farm |url=https://www.bbc.co.uk/news/uk-england-humber-47214591 |work=BBC News |access-date=17 February 2019 |date=15 February 2019}} with full completion expected in the first quarter of 2020.{{cite web |url=https://cleantechnica.com/2019/02/15/worlds-largest-offshore-wind-farm-hornsea-one-generates-first-power/ |title=World's Largest Offshore Wind Farm Hornsea One Generates First Power|access-date=18 February 2019}}

The final monopile foundation was completed in April 2019 and as of 3 May 2019, 28 turbines out of 174 had been installed.{{cite web|url=https://www.offshorewind.biz/2019/04/26/hornsea-one-foundations-all-in-place/ |title=Hornsea One Foundations All In Place|date=26 April 2019|work=Offshore Wind|access-date=28 June 2019}}{{cite web|url=https://www.offshorewind.biz/2019/05/03/bold-tern-installs-turbine-28-at-hornsea-one/ |title=Bold Tern Installs Turbine 28 at Hornsea One|date=3 May 2019|work=Offshore Wind|access-date=28 June 2019}}

The final turbine was installed in October 2019 and the project was completed in early 2020.{{cite web|last1=Shrestha|first1=Priyanka|date=3 October 2019|title=Final turbine installed at 'world's largest' offshore wind farm|url=https://www.energylivenews.com/2019/10/03/final-turbine-installed-at-worlds-largest-offshore-wind-farm/|access-date=6 October 2019|website=Energy Live News}}{{cite web|title=Construction of world's largest offshore wind farm in the UK, nearly complete|url=https://constructionreviewonline.com/2019/10/construction-of-worlds-largest-offshore-wind-farm-in-the-uk-nearly-complete/|website=constructionreviewonline.com| access-date=11 February 2020}}{{cite web|date=30 January 2020|title=World's Largest Offshore Wind Farm Fully Up and Running|url=https://www.offshorewind.biz/2020/01/30/worlds-largest-offshore-wind-farm-fully-up-and-running/|website=OffshoreWIND.biz|access-date=20 September 2020}}

In 2019 the failure of the plant was partially responsible for a large scale nationwide power cut on the evening of 9 August.{{cite news|date=11 August 2019|title=UK power cut: Andrea Leadsom launches government investigation|work=BBC News|publisher=BBC|url=https://www.bbc.co.uk/news/uk-49309691|access-date=12 August 2019}}

At 16:52:33 on Friday 9 August 2019, lightning struck a 400 kV mainland transmission line between Eaton Socon and Wymondley north of London, causing small generators, Little Barford Power Station (641 MW) and Hornsea (737 MW) to unexpectedly disconnect a combined 1,878 MW (1,691 MW maximum single-time) supply within minutes, greater than the 1,000 MW limit. Grid frequency declined, initially below the 'exceptional circumstances' limit at 49.5 Hz, triggering additional generation and then more importantly below 48.8 Hz at which point the first stage of ‘Low Frequency Demand Disconnection’ (LFDD) a form of automatic load shedding commences to stabilise the grid. As part of this 1.1 million customers were disconnected; rail services were disrupted with 371 trains cancelled, 220 part cancelled, and 873 trains delayed. Power was restored at 17:37.{{cite web |title=Technical Report on the events of 9 August 2019 |url=https://www.nationalgrideso.com/document/152346/download |date=6 September 2019 |access-date=6 October 2019}} Hornsea disconnected due to a software flaw, which was fixed the next day.{{cite web |title=Appendices to the Technical Report on the events of 9 August 2019, Appendix D |url=https://www.nationalgrideso.com/document/152351/download |pages=42 |date=6 September 2019 |access-date=6 October 2019}}

File:Hornsea 2 wind farm from the air.jpg

A scoping report for "Project Two" was published in October 2012.{{sfn|SMart Wind|2012a}} The subzone was expected to be developed in a number of phases, with a potential wind turbine capacity of 1.8 GW, in an area of around {{convert|400|km2}} located in the centre of the Hornsea wind farm zone. Project 2 was use the same route for its electrical export cable as Project One, and to use either HVAC or HVDC with a separate onshore substation.{{sfn|SMart Wind|2012a|loc = §1.1.1–1.1.5, §3.3.10–3.311}} Suitable areas for the Project 2 development were identified as being adjacent to the north, east or west of the Zone 1, which was located in the shallowest area of the whole Hornsea zone.{{sfn|SMart Wind|2012a|loc = §3.3.7}} The design considered piled, suction pile, monopile or gravity base foundations for wind turbines of 5 to 15 MW rated power.{{sfn|SMart Wind|2012a|loc = §3.4.7–3.4.14}}

As with Project 1 sea bed conditions and geology consisted of Quaternary period deposits, primarily sediments of sand, till and clays, with the overlying gravel or sand seabed including sandwaves, with the average water depth of {{convert|25|to|30|m}}.{{sfn|SMart Wind|2012a|loc = §5.1.2–5.1.11}}

In 2013 SMart wind signed lease agreements with the Crown Estate for the "Optimus Wind" and "Breesea" areas making up Project 2 of Hornsea wind farm. A planning application for Project 2 was submitted and accepted for examination in early 2015; its wind turbine area was located adjacent northwest of the Project 1 area, with the cable export route following that of Project 1 adjacent on the northward side.{{sfn|SMart Wind|2015}} Planning permission for the development was awarded in August 2016,{{cite news| url =http://www.yorkshirepost.co.uk/news/environment/green-lit-world-s-largest-offshore-wind-farm-just-off-the-yorkshire-coast-1-8070581 | title = Green-lit: World's largest offshore wind farm, just off the Yorkshire coast | first1= Kate| last1 = Proctor| first2= Alex| last2 = Woof | date = 16 August 2016 | work = The Yorkshire Post | access-date =16 August 2016}} for 300 turbines covering {{convert|300|mi2}} at a height of {{convert|190|m|order=flip}} each. At the time of the award, Dong had committed to building 174 turbines, but the whole project is the biggest marine wind farm in the world.{{cite news |last1=Pagnamenta |first1=Robin |title=Biggest offshore wind farm gets the go-ahead |work=The Times |issue=71991 |date=17 August 2016 |page=9|issn=0140-0460}}

By the time construction commenced in 2020, the selected area was to the east and north of Hornsea One and the specification had been set as 165 8 MW turbines giving a rated capacity of 1.4 GW.{{cite web| url=https://hornseaprojects.co.uk/hornsea-project-two/about-the-project#honsea-project-two-timeline-2020| title=Where is Hornsea Two?| website=hornseaprojects.co.uk| accessdate=14 June 2021}} The inter-array cables were supplied by JDR Cable Systems, installed by Seaway 7, and operate at 66 kV.{{cite web |date=24 July 2019 |title=Subsea 7 unit wins cable contract for wind farm offshore UK |url=https://www.power-technology.com/news/subsea-7-cable-contract-uk/ |access-date=6 April 2022 |website=Power Technology }}{{cite web |date=30 August 2018 |title=Hartlepool’s JDR Cables wins multi-million pound contract for world’s biggest offshore wind farm |url=https://www.globalunderwaterhub.com/9871/hartlepools-jdr-cables-wins-multi-million-pound-contract-for-worlds-biggest-offshore-wind-farm |access-date=6 April 2022 |website=Global Underwater Hub}}

As of April 2021, a third of the turbine foundations had been installed and the remaining turbines are set to be installed during the second half of 2021.{{cite web|url=https://www.offshorewind.biz/2021/04/21/offshore-construction-progresses-at-1-4-gw-hornsea-two-offshore-wind-farm/ |title=Offshore Construction Progresses at 1.4 GW Hornsea Two Offshore Wind Farm|date=21 April 2021|website=Offshore Wind|accessdate=21 April 2021}}{{cite web|url=https://www.4coffshore.com/news/construction-well-underway-for-hornsea-2-nid20972.html |title=Construction well underway for Hornsea 2|website=4c Offshore|accessdate=15 April 2021}}

The first turbine was in place by the end of May 2021, and on 23 June 2021 Ørsted announced that the 16th turbine to be added to the Hornsea Two array was the 1,000th turbine they had installed in UK waters, fifteen years after they installed their first, which was part of the 30-turbine Barrow Offshore Wind Farm, off the coast of Cumbria.{{cite web|url=https://www.business-live.co.uk/ports-logistics/1000-offshore-wind-turbines-now-20881169| title=1,000 offshore wind turbines now installed by renewable energy giant Ørsted in UK waters| website=business-live.co.uk| first=David |last=Laister| date=23 June 2021| accessdate=28 June 2021}} Having completed the offshore substation, first power was achieved by 20 December 2021, and became fully operational in August 2022. By doing so, Hornsea Project 2 overtook Hornsea One as the largest offshore wind farm in the world.{{cite news |title=Hornsea 2: North Sea wind farm claims title of world's largest |url=https://www.bbc.co.uk/news/science-environment-62731923 |work=BBC News |accessdate=31 August 2022}} Hornsea Two has two diesel-electric crew ships,{{cite web |title=MHO's New CTVs Have Zero-emissions Capability |url=https://www.oedigital.com/news/490176-mho-s-new-ctvs-have-zero-emissions-capability |website=Offshore Engineer Magazine |accessdate=11 September 2021 |date=26 August 2021}} where crews stay for two weeks while maintaining the turbines.{{cite web |last1=Vorrath |first1=Sophie |title=From nets to nacelles: A day in the life of an offshore wind technician |url=https://reneweconomy.com.au/from-nets-to-nacelles-a-day-in-the-life-of-an-offshore-wind-technician/ |website=RenewEconomy |date=5 December 2023}}

Project 3 will be to the east of Projects 1 and 2, with a capacity of 2.9 GW over {{convert|696|km2}}. DONG Energy (which in November 2017 changed its name to Ørsted{{cite web|title=Ørsted: A new beginning|url=https://orsted.com/en/About-us/About-orsted/About-our-name-change |publisher=Ørsted|access-date=1 May 2018|archive-date=3 April 2018|archive-url=https://web.archive.org/web/20180403112350/https://orsted.com/en/About-us/About-orsted/About-our-name-change |url-status=dead}}) began consultation on the project's development in May 2016.{{cite news | url = https://www.bbc.co.uk/news/uk-england-humber-36206631| title = Consultation starts over Hornsea's third offshore wind farm| work = BBC News Humberside| date =4 May 2016 | access-date =4 May 2016}} Ørsted submitted a Development consent application in 2018 and consent was granted on 31 December 2020.{{cite web |title=Planning Inspectorate |url=https://infrastructure.planninginspectorate.gov.uk/projects/eastern/hornsea-project-three-offshore-wind-farm/ |access-date=1 January 2021}} In early 2023, consent was also given to a battery storage power station at Swardeston,{{cite web |last1=Lee |first1=Andrew |title=Orsted wins green light for 'utility scale' battery plant linked to giant North Sea wind farm {{!}} Recharge |url=https://www.rechargenews.com/energy-transition/orsted-wins-green-light-for-utility-scale-battery-plant-linked-to-giant-north-sea-wind-farm/2-1-1386744 |website=Recharge {{!}} Latest renewable energy news |accessdate=12 January 2023 |date=11 January 2023}} expected at 300 MW / 600 MWh.{{cite web |last1=Green |first1=Molly |title=Ørsted to create one of ‘Europe’s largest’ BESS for Hornsea 3 |url=https://www.solarpowerportal.co.uk/orsted-to-create-one-of-europes-largest-bess-for-hornsea-3/ |website=Solar Power Portal |date=12 June 2024|accessdate=23 November 2024}} Hornsea 3 began construction in 2023, and is expected to complete at the end of 2027.{{cite web |title=Ørsted takes final investment decision on Hornsea 3 Offshore Wind Farm |url=https://hornseaproject3.co.uk/news/2023/12/orsted-takes-final-investment-decision-on-hornsea-3-offshore-wind-farm |access-date=29 December 2023 |website=hornseaproject3.co.uk }}

The wind farm will be equipped with up to 231 Siemens Gamesa 14-236 DD offshore wind turbines, each with a 14MW capacity.

Concerns have been raised by the RSPB over the impact on bird colonies in the region.{{cite news |date=2 January 2021|title=Bird charity warns of harm from new wind farm| url=https://www.bbc.co.uk/news/science-environment-55509225 |work=BBC News|access-date=2 January 2021}} 1,500 nest boxes for kittiwakes were built on a pole offshore in 2023, near RSPB Minsmere and Lowestoft.{{cite web |title=Orsted completes industry-first at Hornsea 3 |url=https://renews.biz/87121/orsted-completes-industry-first-at-hornsea-3/ |date=21 July 2023 |accessdate=25 July 2023}}

Ørsted put forward a plan to add a fourth area to the Hornsea wind farm in 2018, with the area covering {{convert|600|km2}}, and being located adjacent, north-west of Hornsea Project 1. During 2018 and 2019, consultation with the local communities which will be affected by the project took place, with a Development Consent Order application originally intended in the first quarter of 2020.{{cite web |title=About the project |url=https://hornseaprojects.co.uk/hornsea-project-four/about-the-project-4#7 |website=Hornsea Project Four |publisher=Ørsted |access-date=2 August 2020}} However additional consultations and revisions delayed the submission until September 2021, with further analysis needed on the impacts to kittiwake, razorbill and guillemot populations in the Flamborough and Filey Coast Special Protection Area.{{cite web|url=https://www.4coffshore.com/news/%C3%B8rsted-submits-dco-application-for-hornsea-four-nid24368.html|title=Ørsted submits DCO application for Hornsea 4| website=4Coffshore.com|date=19 October 2021| first=Tom |last=Russell|accessdate=20 December 2021}} Part of the site is also scheduled for an underground carbon dioxide storage, leading to conflict over the use of the seabed and the ocean surface.{{cite web |last1=Penman |first1=Hamish |title=BP hands out southern North Sea CCS contract |url=https://www.energyvoice.com/renewables-energy-transition/ccs/uk-ccs/380916/bp-hands-out-southern-north-sea-ccs-contract/ |website=Energy Voice |date=19 January 2022 |accessdate=11 March 2022}}

The project's capacity was unknown by Ørsted due to the ever increasing size of available wind turbines for the project. Government approval for phase four was given by Grant Shapps in July 2023.{{cite news|url=https://www.bbc.co.uk/news/uk-england-humber-66201130|title=Hornsea Four wind farm approved by government|date=14 July 2023|work=BBC News|accessdate=15 July 2023}} Pre-construction site enabling works were expected to commence in the first half of 2025 and completion was expected by 2030.{{cite web |title=Hornsea Four |url=https://hornseaprojects.co.uk/hornsea-project-four |access-date=29 December 2023 |website=hornseaprojects.co.uk}} On 7 May 2025, Orsted wrote that its planned capacity was 2,400 MW.

On 7 May 2025, Orsted announced that it has decided "to discontinue the Hornsea 4 project [...] in its current form. Since the Contract for Difference (CfD) award [...] in September 2024, the [...] Hornsea 4 project has seen several adverse developments relating to continued increase of supply chain costs, higher interest rates, and an increase in the risk to construct and operate Hornsea 4 on the planned timeline".{{cite web|website=orsted.com |date=7 May 2025 |url=https://orsted.com/en/company-announcement-list/2025/05/ortsed-to-discontinue-the-hornsea-4-offshore-wind--143901911 |title=Ørsted to discontinue the Hornsea 4 offshore wind project in its current form |accessdate=7 May 2025}}

• List of offshore wind farms

{{reflist|group="note"}}

{{reflist|30em|refs=

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{{cite press release| url = https://www.gov.uk/government/news/hornsea-offshore-wind-farm-zone-4-project-2-application-accepted-for-examination| title = Hornsea Offshore Wind Farm (Zone 4) – Project 2 application accepted for examination| date = 20 February 2015| publisher = Planning Inspectorate |access-date=27 January 2016}}

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{{cite web| url=http://renews.biz/94135/dong-grabs-hornsea-zone| title = Dong grabs Hornsea zone| date = 21 August 2015| work = renews.biz |access-date=27 January 2016}}

{{cite web| url = http://renews.biz/100867/balfour-grabs-hornsea-gig | title =Balfour grabs Hornsea gig | date = 15 December 2015 | work = renews.biz |access-date=27 January 2016}}

{{cite web| url = http://renews.biz/91208/siemens-wins-1-2gw-monster-order| title =Siemens 1.2GW monster order | date = 3 July 2015 | work = renews.biz |access-date=27 January 2016}}

{{cite web| url =http://renews.biz/87525/fugro-signs-off-at-hornsea-1 | title = Fugro signs off at Hornsea 1| date = 23 March 2015 | work = renews.biz |access-date=27 January 2016}}

{{cite web| url = http://renews.biz/83581/dong-flies-solo-at-hornsea-1 | title = Dong takes control at Hornsea 1| date = 4 February 2015 | work = renews.biz |access-date=27 January 2016}}

{{cite web| url = http://renews.biz/80656/1-2gw-hornsea-1-gets-green-light | title = 1.2GW Hornsea 1 green light | date = 10 December 2014 | work = renews.biz |access-date=27 January 2016}}

{{cite web | url = http://renews.biz/65273/uk-awards-contracts-for-4-5gw | title = UK awards contracts for 4.5GW | date = 23 April 2014 | work = renews.biz | access-date = 27 January 2016 | archive-url = https://web.archive.org/web/20160220062556/http://renews.biz/65273/uk-awards-contracts-for-4-5gw | archive-date = 20 February 2016 | url-status = dead }}

{{cite web| url =http://renews.biz/40093/hornsea-duo-sign-on-dotted-line | title = Hornsea duo signs on dotted line| date = 24 April 2013| work = renews.biz |access-date=27 January 2016}}

}}

{{refbegin}}

• {{cite web| url =http://www.thecrownestate.co.uk/media/5702/ei-km-in-pc-method-052010-round-3-zone-appraisal-and-planning.pdf| title = Round 3 zone appraisal and planning| date = 7 May 2010| publisher =The Crown Estate | ref = {{harvid|Crown Estate|2010}} |access-date=27 January 2016}}
• {{cite web| url =http://www.thecrownestate.co.uk/media/5644/ei-km-in-pc-planning-062013-round-3-offshore-wind-site-selection-at-national-and-project-levels.pdf| title = Round 3 Offshore Wind Site Selection at National and Project Levels| publisher = The Crown Estate | date = June 2013| issue = FINAL v2 | ref = {{harvid|Crown Estate|2013}} |access-date=27 January 2016}}
• {{cite web| url = http://www.thecrownestate.co.uk/media/5701/abpmer_high_level_risk_review.pdf| title = Round 3 Zones : High-Level Risk Review of Physical Processes| author = ABP mer| date = March 2009| publisher = The Crown Estate |access-date=27 January 2016}}

;Zone 1

• {{cite web| url =http://infrastructure.planninginspectorate.gov.uk/projects/yorkshire-and-the-humber/hornsea-offshore-wind-farm-zone-4-project-one/| title= Hornsea Offshore Wind Farm (Zone 4) – Project One| publisher = The Planning Inspectorate|access-date=16 February 2016}}
• {{cite web| url = http://infrastructure.planninginspectorate.gov.uk/wp-content/ipc/uploads/projects/EN010033/1.%20Pre-Submission/EIA/Scoping/Scoping%20Request/Hornsea_Project_One_Scoping_Report%20_FINAL%201st%20Request.pdf| title = Hornsea Project One – Environmental Impact Assessment Scoping Report| date = November 2010| publisher = SMart Wind | ref= {{harvid|SMart Wind|2010}} |access-date=27 January 2016}}
• {{cite web| url = http://infrastructure.planninginspectorate.gov.uk/wp-content/ipc/uploads/projects/EN010033/1.%20Pre-Submission/EIA/Scoping/Scoping%20Request/Hornsea%20Project%20One%20Scoping%20Report%20Addendum%2030-03-2012_plus%20Appendix%202nd%20Scoping%20Request.pdf| title = Hornsea Project One – Addendum to Environmental Impact Assessment Scoping Report| date = March 2012| publisher = SMart Wind | ref= {{harvid|SMart Wind|2012}} |access-date=27 January 2016}}
• {{cite web| url = http://infrastructure.planninginspectorate.gov.uk/wp-content/ipc/uploads/projects/EN010033/2.%20Post-Submission/Application%20Documents/Environmental%20Statement/7.1a%20Non%20Technical%20Summary.pdf| title = Hornsea Offshore Wind Farm Project One : Environmental Statement – Non-Technical Summary (7.1a)| publisher = SMart Wind| date =July 2013 | ref= {{harvid|SMart Wind|2013}} |access-date=27 January 2016}}

;Zone 2

• {{cite web| url =http://infrastructure.planninginspectorate.gov.uk/projects/yorkshire-and-the-humber/hornsea-offshore-wind-farm-zone-4-project-two/| title= Hornsea Offshore Wind Farm (Zone 4) – Project Two | publisher = The Planning Inspectorate|access-date=16 February 2016}}
• {{cite web| url =http://infrastructure.planninginspectorate.gov.uk/wp-content/ipc/uploads/projects/EN010053/1.%20Pre-Submission/EIA/Scoping/Scoping%20Request/121005_EN010053_Scoping%20Report.pdf| title = Hornsea Project Two Environmental Impact Assessment Scoping Report | date = October 2012| publisher = SMart Wind | ref= {{harvid|SMart Wind|2012a}} |access-date=27 January 2016}}
• {{cite web| url =http://infrastructure.planninginspectorate.gov.uk/wp-content/ipc/uploads/projects/EN010053/2.%20Post-Submission/Application%20Documents/Environmental%20Statement/7.4.5.4%20Project%20One%20Project%20Two%20Interface.pdf| work = Hornsea Offshore Wind Farm Project Two Environmental Statement| volume = 4 Introductory Annexes| title = Annex 4.5.4 Project One/Project Two Interface (Document Reference 7.4.5.4)| date = January 2015| ref = {{harvid|SMart Wind|2015}} |access-date=27 January 2016}}

{{refend}}

{{stack|{{Portal|England|Weather|Renewable energy}}}}

• {{cite web| url=http://smartwind.co.uk/| title = SMart Wind Limited| work = smartwind.co.uk }}
• {{cite web | url = http://www.hornseaprojectone.co.uk/en| title = DONG Energy – Hornsea Project One | work = www.hornseaprojectone.co.uk }}
• {{cite web| url = http://www.4coffshore.com/windfarms/hornsea-project-one---heron-wind-united-kingdom-uk81.html | title = Hornsea Project One – Heron Wind| work = www.4coffshore.com }}
• {{cite web| url =http://www.4coffshore.com/windfarms/hornsea-project-one---njord-united-kingdom-uk82.html| title = Hornsea Project One – Njord | work = www.4coffshore.com }}

{{Wind power in the United Kingdom}}

{{Electricity generation in Yorkshire and the Humber}}

Category:Proposed wind farms in England

Category:Offshore wind farms in the North Sea

Category:Round 3 offshore wind farms

Category:Ørsted (company) wind farms

Category:Hornsea

Category:2018 establishments in England

Category:Nationally Significant Infrastructure Projects (United Kingdom)

Category:Energy infrastructure completed in 2021