Large-scale battery energy storage Large-scale battery energy storage Composite insulator (400kV) Composite insulator Concrete (substation foundations) Concrete Transmission connections process (CUSC/STC, Gate 2) Transmission connections process Converter station civil and installation works Converter station civil and insta… Copper (transformer windings) Copper Development consent (DCO under the Planning Act) Development consent Distribution-connected generation (Power Generating Modules) Distribution-connected generation Distribution system (DNO network) Distribution system Electricity customer (premises supplied) Electricity customer Electricity interconnector (cross-border link) Electricity interconnector Extruded-insulation HV power cable (above 30 kV to 500 kV) Extruded-insulation HV power cable Generating station (generation set) Generating station Grain-oriented electrical steel (transformer core) Grain-oriented electrical steel Grid supply point Grid supply point High-voltage switchgear and controlgear High-voltage switchgear and contr… HVDC cable manufacturing (cable factory) HVDC cable manufacturing HVDC cable (subsea and underground) HVDC cable HVDC converter station HVDC converter station HVDC transmission link (onshore and subsea) HVDC transmission link Insulation and interruption gas (SF6 and alternatives) Insulation and interruption gas Independent 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 system Offshore transmission system Offshore wind generating station Offshore wind generating station On-load tap-changer On-load tap-changer Optical wire for overhead lines Optical wire for overhead lines Overhead line conductor Overhead line conductor High-voltage overhead line High-voltage overhead line Power transformer manufacturing Power transformer manufacturing Power transformer (HV/EHV) Power transformer Pre-construction development (surveys, design, consents, tenders) Pre-construction development Regulatory project assessment and funding approval (ASTI / re-openers) Regulatory project assessment and… Skilled electricity network workforce Skilled electricity network workf… Strategic network planning (CSNP / ETYS) Strategic network planning Substation construction (ETP regional delivery) Substation construction Early supply-chain capacity procurement (APM, GGP call-offs) Early supply-chain capacity procu… Tower steelwork (lattice steel members) Tower steelwork Transformer bushing Transformer bushing Transformer insulating oil Transformer insulating oil Transmission-connected demand (data centres, industry, rail) Transmission-connected demand Transmission reinforcement works (TO offer works) Transmission reinforcement works Transmission substation Transmission substation Transmission tower (steel support structure) Transmission tower Underground cable circuit (transmission) Underground cable circuit Voltage-sourced converter (VSC) HVDC technology Voltage-sourced converter (VSC) H… XLPE (cross-linked polyethylene) cable insulation XLPE (cross-linked polyethylene)… Large-scale battery energy storage -> national electricity transmission system Composite insulator -> overhead line Concrete -> substation construction Connections process -> transmission reinforcement works (TO offer) Converter station civil and installation works -> HVDC converter station Copper -> power transformer Development consent -> major transmission project construction Distribution-connected generation -> distribution system Distribution system -> electricity customer Electricity interconnector -> national electricity transmission system Extruded-insulation HV power cable -> underground cable circuit Generating station -> connections process (connection application) Generating station (generation set) -> distribution system Generating station -> national electricity transmission system Grain-oriented electrical steel -> power transformer Grid supply point -> distribution system HV switchgear -> transmission substation HVDC cable -> electricity interconnector HVDC cable -> HVDC transmission link HVDC cable manufacturing -> HVDC cable HVDC converter station -> electricity interconnector HVDC converter station -> HVDC transmission link HVDC transmission link -> national electricity transmission system HVDC transmission link -> transmission substation Insulation and interruption gas -> HV switchgear ISOP (NESO) -> connections process ISOP (NESO) -> national electricity transmission system (co-ordination and direction of flows) ISOP (NESO) -> strategic network planning (CSNP) Major transmission project construction -> national electricity transmission system National electricity transmission system -> grid supply point National electricity transmission system -> transmission-connected demand Offshore transmission system -> national electricity transmission system Offshore wind generating station -> offshore transmission system On-load tap-changer -> power transformer Optical wire -> overhead line High-voltage overhead line -> national electricity transmission system Overhead line conductor -> overhead line Overhead line conductor -> early supply-chain capacity procurement (GGP call-off) Power transformer -> transmission substation Power transformer manufacturing -> power transformer Pre-construction development -> development consent Regulatory funding approval -> major transmission project construction Skilled network workforce -> major transmission project construction Skilled workforce -> power transformer manufacturing Strategic network planning -> pre-construction development Strategic network planning -> regulatory funding approval Substation construction -> transmission substation Early supply-chain capacity procurement -> major transmission project construction Tower steelwork -> transmission tower Transformer bushing -> power transformer Transformer insulating oil -> power transformer Transmission-connected demand -> connections process (demand connection application) Transmission reinforcement works -> national electricity transmission system Transmission substation -> national electricity transmission system Transmission tower -> overhead line Underground cable circuit -> national electricity transmission system VSC converter technology -> HVDC converter station XLPE insulation -> HVDC cable Balfour Beatty Group Limited BAM Nuttall Limited Borealis 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 Limited Eastern Green Link 2 Limited Energy Networks Association Limited (ENA) Electricity North West Limited GE Vernova Inc. Greenlink Interconnector Limited HD Hyundai Electric Co., Ltd. Hitachi Energy UK Limited Hitachi Energy AG (Hitachi Energy Ltd) Hitachi, Ltd. International Electrotechnical Commission (IEC) LS Cable & System Ltd. National Grid Holdings Limited National Grid plc National Energy System Operator Limited (NESO) NeuConnect Britain Ltd Nexans National Grid Electricity Transmission plc (NGET) Nippon Steel Corporation NKT A/S Ofgem (Office of Gas and Electricity Markets) / Gas and Electricity Markets Authority Painter Brothers Limited Prysmian S.p.A. Maschinenfabrik Reinhausen GmbH Koninklijke BAM Groep N.V. (Royal BAM Group) Scottish Power UK plc Scottish Hydro Electric Transmission plc (SSEN Transmission) Siemens Energy Limited (UK) Siemens Energy AG Scottish Power Energy Networks Holdings Limited SP Transmission plc (SP Energy Networks) SSE plc Scottish and Southern Energy Power Distribution Limited Sumitomo Electric U.K. Power Cables Ltd. Sumitomo Electric Industries, Ltd. Trench Group GmbH Parliament of the United Kingdom WoDS 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 specifications BS EN 50341-2-9:2017+A1:2018 Overhead electrical lines exceeding AC 1 kV - National Normative Aspects (NNA) for Great Britain and Northern Ireland Energy 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 2025 Ofgem 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), 2025 National Policy Statement for Electricity Networks Infrastructure (EN-5), December 2025 Energy 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 networks ENA Engineering Recommendation P2 Issue 8 (2023) - Security of Supply Electricity 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: General IEC 60840 Power cables with extruded insulation and their accessories for rated voltages above 30 kV up to 150 kV IEC 61936-1 Power installations exceeding 1 kV AC and 1,5 kV DC - Part 1: AC IEC 62067 Power cables with extruded insulation and their accessories for rated voltages above 150 kV up to 500 kV IEC 62271-1 High-voltage switchgear and controlgear - Part 1: Common specifications IEC 62271-203 AC gas-insulated metal-enclosed switchgear for rated voltages above 52 kV Ofgem 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 2031 Advanced 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 2031 BTNO: new 400 kV double circuit between Bramford and Twinstead - ASTI output, delivery 31 December 2029 Contracts for Difference Allocation Round 7: 8437.50 MW of offshore wind contracts, results published 14 January 2026 CGNC: new 400 kV double circuit between Creyke Beck and the south Humber - ASTI output, delivery 31 December 2031 Connections Action Plan (DESNZ and Ofgem, November 2023): transmission connection dates on average no more than 6 months beyond the requested date, at latest by 2025 EDEU: 400 kV upgrade Brinsworth-Chesterfield-High Marnham double circuits and new High Marnham and Chesterfield 400 kV substations - ASTI output, delivery 31 December 2029 EDN2: new Chesterfield to Ratcliffe-on-Soar 400 kV double circuit - ASTI output, delivery 31 December 2031 Eastern Green Link 1 (E2DC): Torness to Hawthorn Pit 525kV 2GW HVDC link - ASTI output and Ofgem project assessment allowance Eastern Green Link 2 (E4D3): Peterhead to Drax 525kV 2GW HVDC link - ASTI output and Ofgem project assessment allowance Eastern Green Link 3 (E4L5): Peterhead to West Norfolk offshore HVDC, 2GW - ASTI output, target delivery 31 August 2034 Eastern Green Link 4 (TGDC): East Scotland to West Norfolk subsea HVDC, 2GW - ASTI output, target delivery 31 August 2034 Electricity 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 2024 GGP 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 projects Greenlink 500 MW HVDC interconnector: Siemens Energy and Sumitomo Electric contract with Greenlink Interconnector Limited, 21 September 2021 GWNC: new 400kV double circuit South Humber to West Norfolk (Grimsby West to Walpole) - ASTI output, target delivery 31 December 2033 Hitachi 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 components HWUP: uprate Hackney, Tottenham and Waltham Cross 275 kV to 400 kV - ASTI output, delivery 31 December 2028 LS Cable & System additional 155.5 billion won submarine cable expansion at Donghae, 10 August 2023 NeuConnect GB-Germany interconnector: GBP 2.4bn / EUR 2.8bn private investment, 1.4GW, around 725km of cable Bengeworth Road GSP Project Price Control Deliverable (stage 1 and stage 2) - Special Condition 3.44 NGET non-load major project 1: St Johns Wood 275kV Rationalisation (replacement with additional 400kV connection and SGT) - Special Condition 3.47 NGET non-load major project 2: Barking Substation Replacement (400kV SF6 free switchgear at a remote location) - Special Condition 3.47 NGET non-load major project 3: West London Cables Strategy (400kV capable cable and substation revisions) - Special Condition 3.47 Pre-Construction Funding PCD NGT50013: MIDL4 ENWL GSP busbar extension / SGTs / turn-in (GBP 6.19m, delivery 31 March 2031) - Special Condition 3.15 Appendix 2 NGET RIIO-T3 investment plan: up to GBP 31bn capital investment April 2026 to March 2031 NKT 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 2028 Painter 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 2023 Prysmian HVDC cable system contract for Eastern Green Link 2 (c. EUR 1.9bn), 27 February 2024 PTC1: Pentir to Trawsfynydd cable replacement - ASTI output, delivery 31 December 2029 PTNO: North Wales reinforcement - ASTI output, delivery 31 December 2030 RIIO-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 2031 Siemens 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 2025 SSEN Transmission multi-project HVDC converter station agreement with Hitachi Energy (up to five 2GW 525kV corridors) and capacity reservation agreements, July-August 2023 SSEN Transmission HVDC cable framework agreement with Sumitomo Electric and Van Oord (Shetland 2 anchor project), 9 July 2026 Sumitomo 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 2029 Uxbridge Moor substation: new substation connecting more than a dozen data centres from 2029 Ofgem 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 2025/26 DESNZ 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 2025 NGET 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 2025 Nexans opens expanded Halden subsea HVDC cable plant (more than doubles HVDC extruded cable capacity), 6 June 2024 NKT 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 2027 System access bottleneck to delivery reported by NGET for 2025/26 Drag to move, scroll to zoom, click a mark to open it