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Grid issues: United Kingdom
Plans and Prospects
Offshore areas Round 2 areas: North West, Greater Wash, Thames Estuary
Planned offshore windpower 1 GW with planning consent; 7.2 GW waiting for applications
timing Possibly 2010, more realistic: 3 GW by 2010, 6 GW
Transmission System
TSOs National Grid Transco (NGT, England and Wales), Scottish & Southern Energy and Scottish Power (Scotland), SONI (Subsidiary of Northern Ireland Electricity)
Control zones and operators National Grid Transco (Great Britain), SONI (Northern Ireland)
Synchronous Zone Great Britain (England & Wales and Scotland), Island of Ireland (Republic and Northern Ireland)
Final electricity consumption (2002) [TWh] 332,7
Generation capacity (2002) [GW] 77,1
Peak load (2002) 61,7
Minimum load (2002) 20
Power Generation Portfolio [GW]
Nuclear 12,48
Thermal (non-nuclear) 59,66
Hydro 4,378
Wind 0,534
others 0,00
Offshore Power Injection
Suited Substations North West: 132 kV system is weak; 400 kV substations at Deeside, Capenhurst, Frodsham, Stannah and Heysham; Greater Wash: Many connection points available on the 132 kV system close to the coast, but these will not be suitable for the largest wind farms. 400 kV substations at Grimsby, Killingholme, Spalding, Walpole and Norwich;Thames Estuary: many possible connection points at 132 and 400 kV close to the coast, both west and south of the proposed wind farms.
Substation Voltage today 33kV, 132kV, 400kV (and possibly 275 kV in some cases)
Offshore power limit No limit. New transmission capacity can be provided wherever necessary. However, the provision of this infrastructure may well decide the rate at which new offshore wind farms can be connected.
Grid issues
Grid code requirements Power quality, power control, power curtailment, frequency control, voltage control (reactive power), voltage and frequency ride through.
Balancing TSOs are technically responsible for balancing in real time per control zone. All electricity suppliers (wholesalers) are responsible for their portfolio with penalties.
Transmission bottlenecks Transmission bottlenecks exist for north-south transmission, mainly affecting onshore wind power in Scotland and offshore wind power in the North West area and Greater Wash to a minor extent.
Necessary reinforcements North west, above 455 MW will require reinforcements to export power south; Greater Wash, above 1500 MW may require reinforcements; Thames Estuary, no reinforcements required.
Timing of reinforcements Reinforcements for 455 MW of offshore wind in the North West and reinforcements 1000 MW of offshore wind power in the Thames Estuary scheduled for 2006/2007. Major reinforcement of north south interconnector beyond 2010.
External Factors
Import/export/transit Existing HVDC connections:2000 MW to France, 500 MW to Northern Ireland; BritNed HVDC connector (1320 MW) may contribute to supply the London area.
other factors HVDC interconnector Ireland-Wales is under discussion. Not related to offshore wind power.
Trans Border Capacities
Offshore Cable
Connection, first projects Medium voltage AC: 33 kV
Landing, first projects Different techniques including directional drilling and simple excavation. No particular problem with sea defences or environmental protection.
Best option, long term Most projects from now on are likely to use 132 kV or higher.
Connection and energy pricing
Connection charges for DG Deep, likely to move to shallow charging
Connection charges for offshore wind Shallow, however, project developers have to pay for substation reinforcements.
Priority access for renewables none
Minimum price No minimum price. Tradeable certificates with a market size specified by Government.

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Updated September 2008