Celtic Array

The Celtic Array was a proposed UK round 3 offshore wind farm in the Irish Sea south east of the Isle of Man.

Celtic Array
Country
  • United Kingdom
LocationIrish Sea
Coordinates53.771°N 4.411°W / 53.771; -4.411
StatusCancelled
Owner(s)Centrica, Dong Energy
Wind farm
TypeOffshore

The wind farm zone was awarded to Centrica for development in 2012, and in 2012 Centrica formed a joint venture with Dong Energy to develop the zone; a "zone appraisal report" published in 2012 split the area into 3 development zones, with large scale gaps between, primarily to prevent disruption to shipping; the three development zones were estimated to have a total capacity of between 2.9 and 5.4 GW. In 2012 a planning application for the southeastern zone was submitted, as the Rhiannon Wind Farm, with an estimated capacity of 2.2 GW.

In July 2014 the developers terminated plans for the wind farm due to unviable turbine foundation costs.

History and development

In late 2007 the UK Department for Business, Enterprise and Regulatory Reform instigated studies to identify offshore wind sites for around 25 GW of generating capacity;[1] the study, the Offshore Energy Strategic Environmental Assessment (OESEA1, 2009) identified up to 33 GW of potential offshore wind power within English and Welsh territorial waters at sea bed depth of less than 60 m (200 ft); In June 2008 the "Round 3" phase of UK offshore development was announced, subsequently the OESEA plan was adopted, and the Crown Estate designated several areas of potential development, and began a competitive tender process to allocate the sites to developers. Zone development agreements were made in December 2009.[2]

In January 2010 Centrica was awarded the license to develop the Irish Sea round 3 zone; the zone had a total area of 2,200 km2 (850 sq mi) with an estimated potential of 4.2 GW through wind power generation.[3] In March 2012 Centrica and Dong Energy formed a joint venture to develop the wind farm zone, acquiring 50% of Centrica Energy Renewable Investments Ltd., the Irish Sea wind farm development subsidiary, at a cost of £40 million.[4]

The site was split into three zones: a north-east zone of 359 km2 (139 sq mi) with 1 to 2 GW estimated capacity; a south-west zone of 255 km2 (98 sq mi) with 0.5 to 0.8 GW; and a south-eastern zone of 617 km2 (238 sq mi) with 1.4 to 2.6 GW.[5][6][7]

The sea bed of the wind farm zone consisted of sand/gravel, or glacial material including sand/gravel and boulders in Diamicton (mud/sand); below the sea bed surface strata include boulder clays and tills. Bedrock was located at between sea bed level and 100m below sea bed, with deeper levels at the west of the zone.[8]

Significant shipping routes crossed the wind farm zone at several points, including: Liverpool to Belfast shipping crosses the zone roughly between the south-eastern and north-eastern development areas; shipping mainly tankers to the Mersey ports via the pilot station at Point Lynas cross the zone roughly between the southwestern and southeastern development zones; additional Liverpool to Dublin shipping skirted close to the southern edge of the zone, as well as crossing the southeastern zone.[9] To reduce collision risk an additional shipping buffer zone was recommended at the southern and southwestern edges of the southeastern development zone (Rhiannon).[10] Considerations of the main shipping routes were a major factor in forming shapes of the development zones.[11][12]

The south-east zone was the first to be taken forward, with a planning scoping report submitted to the Infrastructure Planning Commission in 2012 as the Rhiannon Wind Farm.[7] In late 2012 the wind farm plan application for the northeast block was delayed based on concerns on its impact on shipping to the Isle of Man (such as that affecting the Isle of Man Steam Packet Company).[13]

In July 2014 plans for the wind farm were terminated by Centrica and Dong, due to the foundation requirements being beyond what was currently financially viable.[14] One factor was the differing ground conditions (sand/rock) which would have required different foundation types, increasing costs.[15]

Rhiannon wind farm

53.675°N 4.238°W / 53.675; -4.238 (Rhiannon offshore wind farm)

An initial scoping report was submitted in 2012;[7][16] the proposed wind farm was on a site ~19 km from Anglesey, ~34 km from the Isle of Man and ~60 km from Cumbria, with a capacity of up to 2.2 GW; initial planning assumed a National grid connection at Anglesey.[17] The initial scoping report supposed wind turbines with between 5 MW and 15 MW capacity.[18]

The wind farm site had a maximum area of 497 km2 (192 sq mi) with water depths of 36 to 83 m (118 to 272 ft) with a tidal range of up to 8.5m.[19]

Public consultation began in late 2012,[20][21] the second consultation phase began in March 2014.[22][23]

By the stage 2 consultation (March 2014) the wind farm power export cables, landfall and national grid connection had been narrowed from 16 export cables with potential landfall and grid connection sites along the west English and north Welsh coasts, to 12 export cables making landfall at 4 sites in North Anglesey connected by an underground cable to a substation at Rhosgoch.[24] The National Grid expects to construct a 400 kV substation adjacent to the onshore Celtic Array wind farm substation, and to make the connection to the mainland electrical gridon the Wylfa Pentir overhead line.[25] The wind farm at stage 2 was expected to consist of between 146 and 440 (15 MW to 4 MW) wind turbines, with up to 8 HVAC offshore substations plus potentially up to 4 HVDC offshore substations; the use of HVDC was not a preferred option. The wind farm would potentially have had up to 4 offshore accommodation platforms for servicing.[26]

gollark: What?
gollark: True, but they would do more badly and complain more.
gollark: Perhaps if you started them on category theory really early...
gollark: I mean, intense abstract things may be out of reach for bored teenagers being taught maths at school.
gollark: ... because if people don't have intuition for the thing, they may just do badly at it and complain?

References
  1. Supporting Information Relating to the Announcement of Round 3 (PDF), The Crown Estate, archived from the original (PDF) on 2014-04-29
  2. Round 3 Offshore Wind Site Selection at National and Project Levels - Non-Technical Summary (PDF), The Crown Estate, pp. 1–2, 11, archived from the original (PDF) on 2014-04-29
  3. Centrica awarded Round Three offshore wind development zone (Press release), Centrica, 8 January 2010
  4. Centrica and DONG Energy establish joint venture to co-develop Round 3 Irish Sea wind farm zone (Press release), Centrica, 21 March 2012
  5. 21. Conclusions and Next Steps 21.2
  6. 6. ZAP Engineering studies and envelope 6.3; Table 6.1
  7. Rhiannon Wind Farm (Round 3 Irish Sea Zone) (Infrastructure Planning Commission). Environmental Impact Assessment Offshore Scoping Report (July 2012)
  8. 7. Geology and Sediment 7.4.1-7.4.2; Figs.7.1, 7.2
  9. 14. Shipping and Navigation 14.4.4-14.4.7 Figs.14.9-14.29
  10. 14. Shipping and Navigation 14.15.1 Figs.14.52
  11. Executive Summary p.vii, Figs.6,7 "Consideration of shipping traffic and adverse weather routes emerged as a key issue [..] safe passage of navigation was one of the main reasons driving the shape and location of the Potential Development Areas"
  12. 5. Identification of Potential Development Areas 5.3.3-5.4.3; Figs.5.8-5.12
  13. "Celtic Array delay Irish Sea wind farm extension plans", BBC News, 19 Dec 2012
  14. "Centrica, Dong ditch R3 Irish Sea", renews.biz, 31 July 2014, archived from the original on 3 August 2014, retrieved 31 July 2014
  15. "Celtic Array Rhiannon wind farm off Anglesey scrapped", www.bbc.co.uk, 31 July 2014
  16. "Irish Sea windfarm proposals lodged with planning agency", BBC News Wales, 14 July 2012
  17. Rhiannon Wind Farm Limited - Environmental Impact Assessment Offshore Scoping Report (July 2012) pp.1, 3, 5; fig.1.1, p.7; fig.3.3, p.17
  18. Rhiannon Wind Farm Limited - Environmental Impact Assessment Offshore Scoping Report (July 2012) 4.9, p.20
  19. Rhiannon Wind Farm Limited - Environmental Impact Assessment Offshore Scoping Report (July 2012) 4.4, p.18; 4.14, p.21;
  20. Rhiannon Wind Farm consultation starts, North Wales Daily Post, 29 Oct 2012
  21. "Stage 1 consultation for Rhiannon Wind Farm, an offshore wind farm proposal in the Irish Sea", www.nwcoastalforum.org.uk, 6 November 2012
  22. "Isle of Man residents consulted on wind farm plans", BBC News Isle of Man, 26 March 2014
  23. Devine, Darren (31 March 2014), "Plans for Europe's largest off-shore wind farm due to be unveiled today", www.walesonline.co.uk
  24. 3. Site Selection & Consideration of Alternatives 3.42-3.63
  25. Rhiannon Wind Farm Connection - Strategic Options Report (PDF), 18 March 2014, 3. pp.10-13; 9. p.50, archived from the original (PDF) on 3 January 2015
  26. 5. Project Description 5.3 (Box 5.1); 5.14-5.15 (Table 5.1); 5.47-5.50; 5.62-5.63

Sources
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