Large-scale battery energy storageLarge-scale battery energy storageComposite insulator (400kV)Composite insulatorConcrete (substation foundations)ConcreteTransmission connections process (CUSC/STC, Gate 2)Transmission connections processConverter station civil and installation worksConverter station civil and insta…Copper (transformer windings)CopperDevelopment consent (DCO under the Planning Act)Development consentDistribution-connected generation (Power Generating Modules)Distribution-connected generationDistribution system (DNO network)Distribution systemElectricity customer (premises supplied)Electricity customerElectricity interconnector (cross-border link)Electricity interconnectorExtruded-insulation HV power cable (above 30 kV to 500 kV)Extruded-insulation HV power cableGenerating station (generation set)Generating stationGrain-oriented electrical steel (transformer core)Grain-oriented electrical steelGrid supply pointGrid supply pointHigh-voltage switchgear and controlgearHigh-voltage switchgear and contr…HVDC cable manufacturing (cable factory)HVDC cable manufacturingHVDC cable (subsea and underground)HVDC cableHVDC converter stationHVDC converter stationHVDC transmission link (onshore and subsea)HVDC transmission linkInsulation and interruption gas (SF6 and alternatives)Insulation and interruption gasIndependent System Operator and Planner (NESO)Independent System Operator and P…Major transmission project construction (ASTI / GGP)Major transmission project constr…National electricity transmission system (GB)National electricity transmission…Offshore transmission systemOffshore transmission systemOffshore wind generating stationOffshore wind generating stationOn-load tap-changerOn-load tap-changerOptical wire for overhead linesOptical wire for overhead linesOverhead line conductorOverhead line conductorHigh-voltage overhead lineHigh-voltage overhead linePower transformer manufacturingPower transformer manufacturingPower transformer (HV/EHV)Power transformerPre-construction development (surveys, design, consents, tenders)Pre-construction developmentRegulatory project assessment and funding approval (ASTI / re-openers)Regulatory project assessment and…Skilled electricity network workforceSkilled electricity network workf…Strategic network planning (CSNP / ETYS)Strategic network planningSubstation construction (ETP regional delivery)Substation constructionEarly supply-chain capacity procurement (APM, GGP call-offs)Early supply-chain capacity procu…Tower steelwork (lattice steel members)Tower steelworkTransformer bushingTransformer bushingTransformer insulating oilTransformer insulating oilTransmission-connected demand (data centres, industry, rail)Transmission-connected demandTransmission reinforcement works (TO offer works)Transmission reinforcement worksTransmission substationTransmission substationTransmission tower (steel support structure)Transmission towerUnderground cable circuit (transmission)Underground cable circuitVoltage-sourced converter (VSC) HVDC technologyVoltage-sourced converter (VSC) H…XLPE (cross-linked polyethylene) cable insulationXLPE (cross-linked polyethylene)…Large-scale battery energy storage -> national electricity transmission systemComposite insulator -> overhead lineConcrete -> substation constructionConnections process -> transmission reinforcement works (TO offer)Converter station civil and installation works -> HVDC converter stationCopper -> power transformerDevelopment consent -> major transmission project constructionDistribution-connected generation -> distribution systemDistribution system -> electricity customerElectricity interconnector -> national electricity transmission systemExtruded-insulation HV power cable -> underground cable circuitGenerating station -> connections process (connection application)Generating station (generation set) -> distribution systemGenerating station -> national electricity transmission systemGrain-oriented electrical steel -> power transformerGrid supply point -> distribution systemHV switchgear -> transmission substationHVDC cable -> electricity interconnectorHVDC cable -> HVDC transmission linkHVDC cable manufacturing -> HVDC cableHVDC converter station -> electricity interconnectorHVDC converter station -> HVDC transmission linkHVDC transmission link -> national electricity transmission systemHVDC transmission link -> transmission substationInsulation and interruption gas -> HV switchgearISOP (NESO) -> connections processISOP (NESO) -> national electricity transmission system (co-ordination and direction of flows)ISOP (NESO) -> strategic network planning (CSNP)Major transmission project construction -> national electricity transmission systemNational electricity transmission system -> grid supply pointNational electricity transmission system -> transmission-connected demandOffshore transmission system -> national electricity transmission systemOffshore wind generating station -> offshore transmission systemOn-load tap-changer -> power transformerOptical wire -> overhead lineHigh-voltage overhead line -> national electricity transmission systemOverhead line conductor -> overhead lineOverhead line conductor -> early supply-chain capacity procurement (GGP call-off)Power transformer -> transmission substationPower transformer manufacturing -> power transformerPre-construction development -> development consentRegulatory funding approval -> major transmission project constructionSkilled network workforce -> major transmission project constructionSkilled workforce -> power transformer manufacturingStrategic network planning -> pre-construction developmentStrategic network planning -> regulatory funding approvalSubstation construction -> transmission substationEarly supply-chain capacity procurement -> major transmission project constructionTower steelwork -> transmission towerTransformer bushing -> power transformerTransformer insulating oil -> power transformerTransmission-connected demand -> connections process (demand connection application)Transmission reinforcement works -> national electricity transmission systemTransmission substation -> national electricity transmission systemTransmission tower -> overhead lineUnderground cable circuit -> national electricity transmission systemVSC converter technology -> HVDC converter stationXLPE insulation -> HVDC cableBalfour Beatty Group LimitedBAM Nuttall LimitedBorealis GmbH (formerly Borealis AG)British Standards Institution (BSI)Cleveland-Cliffs Inc.Department for Energy Security and Net Zero (DESNZ)Dow Inc.Eastern Green Link 1 LimitedEastern Green Link 2 LimitedEnergy Networks Association Limited (ENA)Electricity North West LimitedGE Vernova Inc.Greenlink Interconnector LimitedHD Hyundai Electric Co., Ltd.Hitachi Energy UK LimitedHitachi Energy AG (Hitachi Energy Ltd)Hitachi, Ltd.International Electrotechnical Commission (IEC)LS Cable & System Ltd.National Grid Holdings LimitedNational Grid plcNational Energy System Operator Limited (NESO)NeuConnect Britain LtdNexansNational Grid Electricity Transmission plc (NGET)Nippon Steel CorporationNKT A/SOfgem (Office of Gas and Electricity Markets) / Gas and Electricity Markets AuthorityPainter Brothers LimitedPrysmian S.p.A.Maschinenfabrik Reinhausen GmbHKoninklijke BAM Groep N.V. (Royal BAM Group)Scottish Power UK plcScottish Hydro Electric Transmission plc (SSEN Transmission)Siemens Energy Limited (UK)Siemens Energy AGScottish Power Energy Networks Holdings LimitedSP Transmission plc (SP Energy Networks)SSE plcScottish and Southern Energy Power Distribution LimitedSumitomo Electric U.K. Power Cables Ltd.Sumitomo Electric Industries, Ltd.Trench Group GmbHParliament of the United KingdomWoDS Transmission plc (West of Duddon Sands OFTO)Ofgem Electricity Transmission Advanced Procurement Mechanism decision (20 March 2025)Ofgem Decision on accelerating onshore electricity transmission investment (ASTI framework, 15 December 2022)BS EN 50341-1:2012 Overhead electrical lines exceeding AC 1 kV - General requirements. Common specificationsBS EN 50341-2-9:2017+A1:2018 Overhead electrical lines exceeding AC 1 kV - National Normative Aspects (NNA) for Great Britain and Northern IrelandEnergy Act 2013 Part 2 Chapter 2 - Contracts for Difference (CFD counterparty, direction to offer to contract, allocation rounds)Ofgem Decision on Connections Reform Package (TM04+), 15 April 2025Ofgem Decision on the framework for the Future System Operator's Centralised Strategic Network Plan (OFG1163, 13 December 2023)Connection and Use of System Code (CUSC)Electricity Act 1989 (1989 c. 29)Overarching National Policy Statement for energy (EN-1), 2025National Policy Statement for Electricity Networks Infrastructure (EN-5), December 2025Energy Act 2023 (2023 c. 52)ENA Engineering Recommendation G99 Issue 2 (10 March 2025) - Requirements for the connection of generation equipment in parallel with public distribution networksENA Engineering Recommendation P2 Issue 8 (2023) - Security of SupplyElectricity Transmission Licence Standard Conditions (Ofgem consolidated full set, August 2026)Grid Code (NESO, Issue 6 Revision 45, 13 August 2026)IEC 60076-1 Power transformers - Part 1: GeneralIEC 60840 Power cables with extruded insulation and their accessories for rated voltages above 30 kV up to 150 kVIEC 61936-1 Power installations exceeding 1 kV AC and 1,5 kV DC - Part 1: ACIEC 62067 Power cables with extruded insulation and their accessories for rated voltages above 150 kV up to 500 kVIEC 62271-1 High-voltage switchgear and controlgear - Part 1: Common specificationsIEC 62271-203 AC gas-insulated metal-enclosed switchgear for rated voltages above 52 kVOfgem electricity interconnector cap and floor regime (decision of 6 May 2020 on changes to enable project finance solutions)National Grid Electricity Transmission plc electricity transmission licence Special Conditions (September 2026)Planning Act 2008 (2008 c. 29)RIIO-3 Final Determinations - Electricity Transmission (RIIO-ET3 price control, 1 April 2026 to 31 March 2031; Ofgem decision of 4 December 2025)National Electricity Transmission System Security and Quality of Supply Standard (SQSS)System Operator - Transmission Owner Code (STC)AENC: new 400 kV double circuit in north East Anglia - ASTI output, delivery 31 December 2031Advanced Procurement Mechanism allowance in RIIO-ET3 (~GBP 4bn to secure supply chain capacity)ATNC: new 400 kV double circuit in south East Anglia - ASTI output, delivery 31 December 2031BTNO: new 400 kV double circuit between Bramford and Twinstead - ASTI output, delivery 31 December 2029Contracts for Difference Allocation Round 7: 8437.50 MW of offshore wind contracts, results published 14 January 2026CGNC: new 400 kV double circuit between Creyke Beck and the south Humber - ASTI output, delivery 31 December 2031Connections Action Plan (DESNZ and Ofgem, November 2023): transmission connection dates on average no more than 6 months beyond the requested date, at latest by 2025EDEU: 400 kV upgrade Brinsworth-Chesterfield-High Marnham double circuits and new High Marnham and Chesterfield 400 kV substations - ASTI output, delivery 31 December 2029EDN2: new Chesterfield to Ratcliffe-on-Soar 400 kV double circuit - ASTI output, delivery 31 December 2031Eastern Green Link 1 (E2DC): Torness to Hawthorn Pit 525kV 2GW HVDC link - ASTI output and Ofgem project assessment allowanceEastern Green Link 2 (E4D3): Peterhead to Drax 525kV 2GW HVDC link - ASTI output and Ofgem project assessment allowanceEastern Green Link 3 (E4L5): Peterhead to West Norfolk offshore HVDC, 2GW - ASTI output, target delivery 31 August 2034Eastern Green Link 4 (TGDC): East Scotland to West Norfolk subsea HVDC, 2GW - ASTI output, target delivery 31 August 2034Electricity Transmission Partnership: c. GBP 8bn substation construction work across c.130 projects over RIIO-T3 (launched July 2025)GE Vernova expansion of Stafford, UK HVDC valve and converter transformer facilities, 24 September 2024GGP programmatic call-off contracts for overhead line equipment (~GBP 74m; 10,330km conductor, 619km optical wire, 21,647 insulators)Great Grid Partnership: GBP 9bn framework with seven delivery partners for onshore major transmission projectsGreenlink 500 MW HVDC interconnector: Siemens Energy and Sumitomo Electric contract with Greenlink Interconnector Limited, 21 September 2021GWNC: new 400kV double circuit South Humber to West Norfolk (Grimsby West to Walpole) - ASTI output, target delivery 31 December 2033Hitachi Energy USD 106m expansion of the Alamo, Tennessee transformer component (bushings) facility (operational by mid-2027)Hitachi Energy additional USD 250m+ by 2027 for global production of critical transformer componentsHWUP: uprate Hackney, Tottenham and Waltham Cross 275 kV to 400 kV - ASTI output, delivery 31 December 2028LS Cable & System additional 155.5 billion won submarine cable expansion at Donghae, 10 August 2023NeuConnect GB-Germany interconnector: GBP 2.4bn / EUR 2.8bn private investment, 1.4GW, around 725km of cableBengeworth Road GSP Project Price Control Deliverable (stage 1 and stage 2) - Special Condition 3.44NGET non-load major project 1: St Johns Wood 275kV Rationalisation (replacement with additional 400kV connection and SGT) - Special Condition 3.47NGET non-load major project 2: Barking Substation Replacement (400kV SF6 free switchgear at a remote location) - Special Condition 3.47NGET non-load major project 3: West London Cables Strategy (400kV capable cable and substation revisions) - Special Condition 3.47Pre-Construction Funding PCD NGT50013: MIDL4 ENWL GSP busbar extension / SGTs / turn-in (GBP 6.19m, delivery 31 March 2031) - Special Condition 3.15 Appendix 2NGET RIIO-T3 investment plan: up to GBP 31bn capital investment April 2026 to March 2031NKT around EUR 2bn capacity expansion 2025-2028 (Karlskrona new factory, Cologne expansion, cable-laying vessel; operational 2027)OPN2: new 400kV substations and circuits between Norton to Osbaldwick circuits and Monk Fryston - ASTI output, allowance GBP 368,126,448, delivery 31 December 2028Painter Brothers new tower steelwork manufacturing facility at Hereford (15,000 tonnes per annum, by 2028)Prysmian HVDC cable system contract for Eastern Green Link 1 (c. EUR 850m), 30 November 2023Prysmian HVDC cable system contract for Eastern Green Link 2 (c. EUR 1.9bn), 27 February 2024PTC1: Pentir to Trawsfynydd cable replacement - ASTI output, delivery 31 December 2029PTNO: North Wales reinforcement - ASTI output, delivery 31 December 2030RIIO-ET3 Final Determinations: baseline totex allowances GBP 10.7bn for the three TOs, 1 April 2026 to 31 March 2031 (4 December 2025)SCD1 (Sea Link): new offshore HVDC link between Suffolk and Kent option 1 - ASTI output, delivery 31 December 2031Siemens Energy EUR 220m expansion of the Nuremberg transformer factory (+16,000 m2, +50% capacity, available by 2028)SSEN Transmission converter station contracts awarded to Hitachi Energy for Spittal-Peterhead and Western Isles links, 16 December 2025SSEN Transmission multi-project HVDC converter station agreement with Hitachi Energy (up to five 2GW 525kV corridors) and capacity reservation agreements, July-August 2023SSEN Transmission HVDC cable framework agreement with Sumitomo Electric and Van Oord (Shetland 2 anchor project), 9 July 2026Sumitomo Electric GBP 350m subsea cable factory at the Port of Nigg, Scotland (ground breaking 14 May 2024)TKRE: Tilbury to Grain and Tilbury to Kingsnorth upgrade - ASTI output, delivery 31 December 2029Uxbridge Moor substation: new substation connecting more than a dozen data centres from 2029Ofgem consultation: ASTI Material Scope Change and Early Construction Funding for EGL3, EGL4 and GWNC (11 September 2025 to 10 October 2025)Ofgem approval of the Connections Reform package (TM04+), 15 April 2025, and its reported impact on NGET connection delivery in 2025/26DESNZ consultation: Accelerating electricity network connections for strategic demand (11 March 2026 to 15 April 2026)Ofgem sets new target dates for GWNC (December 2033) and EGL3/EGL4 (August 2034) after project redesign, 9 December 2025NGET incentivised loss of supply event, April 2025 (28.9 MWh energy not supplied in 2025/26)Disposal of the Electricity System Operator to the UK Government on 1 October 2024 (formation of NESO)Fire at the IFA1 converter station, Sellindge, Kent (September 2021)NESO confirms reformed connections pipeline: 283 GW generation and storage and 99 GW transmission connected demand moved forward, 8 December 2025Nexans opens expanded Halden subsea HVDC cable plant (more than doubles HVDC extruded cable capacity), 6 June 2024NKT designated preferred bidder / preferred supplier for the Eastern Green Link 3 525 kV HVDC cable system (2025)North Hyde substation fire and outage (March 2025)Ofgem call for input: Growing Great Britain's electricity network supply chains (opened 25 March 2026, deadline 10 May 2026)Ofgem disallowances on NGET RIIO-T2 re-opener funding requests, 2025/26 (89% approved against 95% target)Sumitomo Electric Nigg factory: cable manufacturing start moves from 2026 (ready for commissioning) to 2Q 2027System access bottleneck to delivery reported by NGET for 2025/26

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  1. Web as at 12 Sept 2026Reports

    UK Grid Web, September 2026

    The first verified map of the UK electricity transmission build-out. 48 nodes, 58 flows and 1,347 sourced facts, plus an honest register of what it could not prove.