Hornsea Wind Farm
Hornsea Wind Farm is a Round 3 wind farm under construction in the North Sea off the coast of England.
The wind farm is planned to have a total capacity of up to 6 gigawatt.
The development has been split into a number of subzones. The 1.2 GW Project 1 gained planning consent in 2014; a second 1.4 GW Project 2 was given planning consent in 2016. In 2016 a third subzone was split into two projects Hornsea 3 and 4, with approximate capacities of 1–2 GW and 1 GW, increasing the capacity of the developed project to a maximum of 6 GW.
Construction of the first phase started in January 2018, and the first turbines began supplying power to the UK national electricity grid in February 2019.
History
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. The Hornsea development zone was awarded to a joint venture 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. The Hornsea site has a total area of, and is from land at the closest point; water depth in the zone is from, with a tidal range of, and typical annual wave height of. The surface of the seabed consists primarily of sands and gravel.
In 2011 the Danish firm Ørsted A/S became a partner in SMart Wind. In early 2015 Ørsted A/S 100% owner of the first phase, Project 1, of the scheme. Ørsted acquired rights to the remaining subzones of the Hornsea development 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. The changes increased the potential generating capacity of the windfarm to 6 GW, with Hornsea Three estimated at 1–2 GW and Hornsea Four at about 1 GW.
In 2019 the failure of the plant was partially responsible for a large scale nationwide power cut on the evening of 9 August.
Hornsea Project 1
The initial scoping report for "Project One" within the Hornsea zone identified it as a subzone of 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. 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. Later DONG Energy added the consideration to use HVAC export cables. The chosen cable export was planned to make landfall at Horsehoe Point, then passing west and northwest to a substation near Killingholme Power Station, North Killingholme in North Lincolnshire.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 thick, with for sandwaves within the area varying in height by. Project 1 water depths were generally.
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 contract for difference renewable subsidies by the UK government in April 2014. Hornsea Project 1 was given planning consent in December 2014. The 'contract for difference' strike price was £140 per MWh. 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 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. 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.
DONG Energy formally committed to building the wind farm in early 2016. The expected completion date for the project was 2020. 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 million and $250 million contracts to supply 220 kV AC export cables in March/April 2016. In late 2016 JDR Cables was contracted to supply of inter-array subsea power cables for the wind farm; Nexans was awarded a contract for of inter-array cables; and EEW was awarded a contract to supply 116 monopiles.
Bladt Industries/Offshore Structures Ltd. was awarded a contract for 96 tower transition pieces in early 2017, to be constructed at Aalborg, Denmark and Billingham, UK.
Construction
Construction of the onshore cable route was begun in late 2016 under J. Murphy & Sons.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.
The first foundation of the new windpark was installed by DEME Group's subsidiary GeoSea in 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.
Hornsea 1 began supplying power to the UK national electricity grid in February 2019, with full completion expected in the first quarter of 2020.
The final monopile foundation was completed in April 2019 and as of 3 May 2019, 28 turbines out of 174 had been installed.
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 and Hornsea to unexpectedly disconnect a combined 1,878 MW supply within minutes, greater than the 1,000 MW limit. Grid frequency declined to 48.8 Hz, below the limit at 49.5 Hz, and 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. Hornsea disconnected due to a software flaw, which was fixed the next day.
The final turbine was installed in October 2019 and the project is expected to complete in early 2020.
Hornsea Project 2
A scoping report for "Project Two" was published in October 2012. 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 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. 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. The design considered piled, suction pile, monopile or gravity base foundations for wind turbines of 5 to 15 MW rated power.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.
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. Planning permission for the development was awarded in August 2016, for 300 turbines covering at a height of 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.
Turbine installation is expected to commence in 2021. When operational in 2022, Hornsea Project 2 will be the biggest offshore wind farm in the world.