Developing offshore grids : An integrated approach Place your chosen image here. The four corners must just cover the arrow tips. For covers, the three pictures should be the same size and in a straight line. Andrew Hiorns Integrated offshore networks: the context of our work Sustainability We are interested in establishing workable arrangements at the lowest costs for UK consumers such that: The potential deliverability of offshore wind is maximised Security of supply and network resilience are maximised The overall cost to consumers is minimised Affordability The scale of potential offshore a Offshore wind leased wind necessitates reflection on capacity* the delivery challenges: 1GW Security of supply 7GW European interconnection Technology development Security of 32GW supply Supply chain capability Planning consents Financing Round 1 Round 2 Round 3 Skills * Source: DECC website 2 http://www.decc.gov.uk/en/content/cms/what_we_do/uk_supply/energy_mix/renewable/policy/offshore/wind_leasing/wind_leasing.aspx 1 Assumptions: Generation mix scenarios 2008/09 TRANSMISSION SYSTEM AS AT 31st DECEMBER 2007 400kV Substations 275kV Substations Slow Progression 132kV Substations 400kV Circuits 275kV Circuits 132kV Circuits Major Generating Sites Including Pumped Storage Pentland Firth Connected at 400kV THE SHETLAND ISLANDS 6 Connected at 275kV 9,724MW offshore wind in 2020 Hydro Generation 23,174MW offshore wind in 2030 1 21% renewable electricity generation 2020 target missed 5 7 8 9 2 10 Gone Green 4 3 16,374MW offshore wind in 2020 3 Tongland 2 2 14 26,354MW offshore wind in 2030 1 3 4 1 32% renewable electricity generation 4 2 3 17 16 2020 target hit 15 9 4 5 7 6 14 11 13 13 12 12 10 11 Accelerated growth 5 9 10 7 8 32,239MW offshore wind in 2020 6 9 5 51,552MW offshore wind in 2030 8 43% renewable electricity generation 6 2020 target exceeded 7 3 Technology Assumptions: New technology is needed under both a radial & integrated solution HVDC cables AC cables Technology is still developing Appropriate only over shorter distances 2-3 year development lead times for the Capacitive effects increase exponentially larger cables over distance Cables where lead times exceed 2-3 Reactive compensation required, but years not used in our study before 2020 ineffective over distance, reducing real power capacity Platform design Smart grids Currently bespoke by project / application Scope for standardisation under an Could be developed as part of an integrated solution integrated solution We have not assumed radical technology solutions pre 2020 4 2 Interaction with onshore TRANSMISSION SYSTEM REINFORCEMENTS Power transfers Dounreay Thurso REINFORCED NETWORK Mybster Stornoway Cassley Dunbeath 400kV Substations Lairg 275kV Substations THE SHETLAND ISLANDS Brora 400kV CIRCUITS North-South will increase Shin 275kV CIRCUITS Grudie Mossford Major Generating Sites Including Pumped Storage Bridge Alness Conon Orrin Elgin Fraserburgh Luichart Ardmore Macduff St. Fergus Connected at 400kV Deanie Dingwall Cu llig ran Keith Strichen Connected at 275kV Aigas Inverness Nairn How might these be managed? Bla ckh illock Dunvegan Kilmorack Peterhead Hydro Generation Beauly Fasnakyle Dyce Glen Kintore Persley Broadford Morrison Woodhill Willowdale Foyers Ceannacroc Boat of Fort Augustus Garten Clayhills Under Construction or ready to start Tarland Craigiebuckler Redmoss Invergarry Construction subject to consents Quoich Fiddes Fort William Errochty Errochty Power Station Rannoch Clunie Bridge of Dun Very strong need case Tummel Lunanhead Bridge Tealing Cashlie Dudhope Arbroath Lochay Lyndhurst Milton of Craigie Radial solutions Taynuilt K illin Finlarig Charleston Cruachan Da lm ally Burghmuir Dudhope Glenagnes Strong need case St. Fillans Nant Clachan SCOTTISH HYDRO-ELECTRIC Cup ar TRANSMISSION Inveraray Glenrothes Sloy Leven Devonside Westfield Red house W h is tl ef ie ld Stirling K inca rdine Glenniston Port Mossmorran Future requirement, but no strong Dunfe rmline Ann Lon gann et B onnybridge I verkeithing Dunoon Helensbu rgh Grang emou th Shrubh ill Cockenzie need case to commence Dun bar Sp ango Devol Strathleven Telford Rd. Portobello Valley M oor Broxburn Gorgie Torness Erskine Cu mbe rn auld Bathg ate Wh ite hou se Inverkip La mbh ill at present Ea ste rho use Radial connections to the nearest landing point L ivingsto n Kaimes Cu rrie Newarthill Clydes Neilston Mill Hun tersto n Berwick Fa rm Wishaw Hunterston Busby Strathave n Blacklaw Kilwinning Whitelee East Series Capacitors K ilmarnock Kilbride Saltcoats To wn South Linm ill Eccles Carradale Me ado whea d G a la sh ie ls Kilmarnock Coalburn South Ayr SP TRANSMISSION LTD. and then additional onshore reinforcements to Coylton Elvanfoot Ha wick Ma ybole NGC Gretna Blyth Du mfries Ecclefecha n provide additional capacity (minimum offshore Auchencrosh Fourstones New ton T ynemouth Stewart Harker South Shields Chapelcross S te lla West West Boldon Glenluce Tongland Offerton Hawthorne Pit Hart Moor B6 Spennymoor Hartlepool costs v’s maximum onshore costs) Saltholme Tod Point Grangetown Norton Greystones Lackenby Hutton Radial connections extended significantly to Heysham Quernmore Poppleton Osbaldwick Thornton Bradford West Kirkstall Stanah Skelton Creyke Beck Padiham Grange Monk Fryston Saltend North avoid onshore reinforcement (maximum Saltend South Penwortham Elland Drax Killingholme Eggborough Humber Refinery B7 Rochda le Ferrybridge Keadby Washway South Templeborough Thorpe Humber Farm Kearsley Whitegate West Kirkby Marsh Bank Grimsby South Melton Lister Stalybridge West Wylfa Manchester Pitsmoor Drive Ra in hill Stocksbridge Aldwarke West Carrington Bredbury Winco Bank Burton Birkenhead Thurcroft offs hore cos ts v ’s m in imum ons hore cos ts ) Neepsend Fiddlers Daines Sheffield City Ferry Brinsworth Cottam Capenhurst Frodsham Jordanthorpe Norton Lees Pentir Macclesfield Chesterfield Deeside High Dinorwig Marnham Staythorpe Legacy Ffestiniog Cellarhead Bicker Fenn Willington Optimum balance sought between radial Trawsfynydd Ratcliffe Drakelow Walpole Rugeley Spalding North Norwich Ironbridge Bushbury Main Willenhall Bustleholm B8 Sh re wsbu ry Enderby Penn Hams Nechells Hall offshore costs vs onshore costs (ODIS) Ocker Hill Coventry O ldbury Kitwell Berkswell Sizewell Burwell Feckenham Main Bishops Grendon Eaton Wood Socon Patford Bramford Bridge East Sundon Claydon Pelham Wymondley Leighton Braintree Buzzard Rassau Walham Rye House Waltham Imperial Brimsdown Cross Park Swansea Cowley Pembroke Watford Elstree Hackney North Amersham Main Rayleigh Main Baglan Cilfynydd Whitson Culham Mill Hill Tottenham Redbridge Warley B9 Minety Didcot Bay Upper Boat Uskmouth Iron Acton Willesden West Thurrock Margam Barking Coryton Alpha Steel Iver Ealing Northfleet East Pyle N.Hyde Singlewell Seabank City Rd W.Ham Tilbury Grain Cowbridge St Johns Tremorfa Laleham Wood New Hurst Cross Kingsnorth Integrated solution Aberthaw Cardiff East West Kemsley Melksham Bramley Weybridge Chessington Rowdown Littlebrook Beddington Fleet Canterbury Wimbledon North Hinkle y Po in t Sellindge Bridgwater Alverdiscott Bolney Nursling Taunton Ninfield E de F Dungeness Marchwood Lovedean Axminster Mannington Fawley Botley Wood Exeter Designs fully integrated to minimise total cost Chickerell Langage Abham Landulph Indian Queens ISSUE B 12-02-09 41/177619 C Collins Bartholomew Ltd 1999 and impact on environment 5 Increased supply security by integration Assuming transmission circuit availability of 95% Annual load factor of offshore wind generation ~40% Radial C1Case 1 -RdilRadial connec tion = 5% x 40% = 2% of installed capacity Total wind generation curtailment = 2% Case 2 – Integrated, sufficient transmission capacity to accommodate 100% wind generation output Intact offshore network, Wind generation output curtailment = 0% Outage of transmission network, Wind generation output curtailment Integrated = 5% x 5% x 40% = 0.1% of installed capacity Total wind generation curtailment = 0.1% Case 3 – Integrated, sufficient transmission capacity to accommodate 90% wind generation output, Intact curtailment = 2.3% Outage curtailment = 5% x 5% x 40% = 0.1% of installed capacity Total wind generation curtailment = 2.4% 6 3 Radial and Integrated UK Offshore Radial solution Integrated solution 7 Design Options Radial 1GW cable to shore 1GW cables to shore 1GW cables to shore 1GW cables to shore Clustered 2GW cable to shore 2GW cable to shore 2GW cables to shore 2GW cab les to s ho re Integrated 2GW cable to shore 2GW cables to shore 2GW cables to shore 2GW cables to shore 8 4 Interaction with interconnectors 1 Case 1 – Radial wind with 100% connection transmission capacity Offshore Wind Output 110 100 CT • Very little restriction of wind output 90 CWF 80 • Transmission utilisation 35-45% 70 Un-utilised transmission 60 50 Output % 40 30 20 CT 10 0 1 501 1001 1501 2001 2501 3001 3501 4001 4501 5001 5501 6001 6501 7001 7501 8001 8501 CWF =CT Time (hours) Case 2 – Wind and interconnection at 100% transmission capacity Offshore Wind Output 110 100 • Potentially either heavily curtailment of wind 90 CT CWF 80 generation output or interconnector trading 70 60 • Potentially 100% transmission utilisation Interconnection 50 Output % 40 • Limitations on ability to use interconnectors 30 20 exist nearly all times 10 CT CI 0 1 501 1001 1501 2001 2501 3001 3501 4001 4501 5001 5501 6001 6501 7001 7501 8001 8501 Time (hours) CT -CI CWF =CT = CI Period when there are potential conflicts 9 Interaction with interconnectors