| Aberdeen Offshore Wind Farm Limited | 28 | 2024-12 |
| Aes Kilroot Power Limited | 35 | 2024-12 |
| Atlantica Yield PLC | 36 | 2025-12 |
| Axpo UK Limited | 8 | 2018-03 |
| Baglan Operations Limited | 19 | 2020-09 |
| Barrow Offshore Wind Limited | 21 | 2024-12 |
| Beatrice Offshore Windfarm Limited | 28 | 2026-03 |
| British Gas Trading Limited | 15 | 2025-12 |
| Britned Development Limited | 25 | 2025-12 |
| Bryt Energy Limited | 13 | 2026-06 |
| Bulb Energy Ltd | 18 | 2021-09 |
| Business Power and Gas Limited | 17 | 2026-03 |
| Cadent Gas Limited | 27 | 2026-03 |
| Carrington Power Limited | 43 | 2025-12 |
| Centrica Energy Marketing Limited | 12 | 2020-06 |
| Centrica PLC | 46 | 2025-12 |
| Clyde Windfarm (Scotland) Limited | 20 | 2026-03 |
| Coolkeeragh Esb Limited | 40 | 2025-12 |
| Corona Energy Retail 2 Limited | 20 | 2026-03 |
| Corona Energy Retail 4 Limited | 14 | 2026-03 |
| Cramlington Renewable Energy Developments Limited | 22 | 2025-12 |
| Cubico Sustainable Investments Limited | 30 | 2025-12 |
| Daikin Airconditioning UK Limited | 41 | 2026-03 |
| Dragon Lng Limited | 21 | 2026-06 |
| Drax Power Limited | 49 | 2025-12 |
| Drax Pumped Storage Limited | 50 | 2025-12 |
| Drax River Hydro Limited | 59 | 2025-12 |
| Dual Energy Direct Limited | 6 | 2021-03 |
| Dudgeon Offshore Wind Limited | 22 | 2025-12 |
| E D F Trading Limited | 17 | 2025-12 |
| E.on Climate & Renewables UK Developments Limited | 25 | 2025-12 |
| E.on Climate & Renewables UK Humber Wind Limited | 15 | 2025-12 |
| E.on Climate & Renewables UK London Array Limited | 23 | 2025-12 |
| E.on Energy Solutions Limited | 42 | 2025-12 |
| E.on UK Chp Limited | 40 | 2025-12 |
| E.on UK Energy Markets Limited | 3 | 2025-12 |
| E.on UK PLC | 42 | 2025-12 |
| E.on UK Steven’s Croft Limited | 21 | 2025-12 |
| East Anglia One Limited | 28 | 2025-12 |
| Eastern Power Networks PLC | 4 | 2026-03 |
| Edf Energy (Thermal Generation) Limited | 63 | 2022-12 |
| Edf Energy Customers Limited | 36 | 2025-12 |
| Edf Energy Nuclear Generation Limited | 51 | 2025-12 |
| Edf Energy PLC | 63 | 2025-12 |
| Edf Energy Renewables Limited | 60 | 2025-12 |
| Eggborough Power Limited | 30 | 2020-06 |
| Electricity North West Limited | 32 | 2025-12 |
| Electricity Plus Supply Limited | 12 | 2026-03 |
| Engie Fm Limited | 34 | 2025-12 |
| Engie Gas Limited | 26 | 2025-12 |
| Ep Ballylumford Limited | 30 | 2025-12 |
| Ep Langage Limited | 29 | 2025-12 |
| Ep Ni Energy Limited | 35 | 2024-12 |
| Ep Shb Limited | 28 | 2025-12 |
| Ep UK Investments Ltd | 31 | 2025-12 |
| Extra Energy Supply Limited | 48 | 2018-06 |
| Fallago Rig Windfarm Limited | 45 | 2025-12 |
| Ferrybridge Mfe 2 Limited | 17 | 2021-03 |
| Ferrybridge Mfe Limited | 18 | 2021-03 |
| First Hydro Company | 21 | 2025-12 |
| First Utility Limited | 24 | 2023-06 |
| Galloper Wind Farm Limited | 33 | 2025-12 |
| Gas Plus Supply Limited | 22 | 2026-03 |
| Gazprom Marketing & Trading Limited | 37 | 2025-12 |
| Gazprom Marketing & Trading Retail Limited | 18 | 2025-12 |
| Grangemouth Chp Limited | 33 | 2025-12 |
| Greater Gabbard Offshore Winds Limited | 22 | 2026-03 |
| Griffin Wind Farm Limited | 21 | 2025-09 |
| Gunfleet Sands Limited | 14 | 2024-12 |
| Haven Power Limited | 13 | 2025-12 |
| Horizon Nuclear Power Services Limited | 30 | 2018-09 |
| Horizon Nuclear Power Wylfa Limited | 28 | 2018-09 |
| Hudson Energy Supply UK Limited | 18 | 2025-12 |
| Hywind (Scotland) Limited | 17 | 2025-12 |
| Independent Pipelines Limited | 4 | 2024-06 |
| Ineos Energy Trading Limited | 7 | 2025-12 |
| Ineos Infrastructure (Grangemouth) Limited | 49 | 2025-12 |
| Ineos Runcorn (Tps) Limited | 24 | 2025-06 |
| Infinis Limited | 41 | 2026-03 |
| Inner Dowsing Wind Farm Limited | 12 | 2025-12 |
| Innogy Renewables UK Limited | 33 | 2025-12 |
| International Power Ltd. | 37 | 2021-12 |
| Ipm Energy Trading Limited | 13 | 2019-12 |
| Keadby Generation Limited | 27 | 2026-03 |
| Kemsley Chp Limited | 49 | 2025-12 |
| Kentish Flats Limited | 30 | 2024-12 |
| Last Mile Electricity Limited | 7 | 2026-03 |
| Lightsource Bp Renewable Energy Investments Limited | 39 | 2025-12 |
| Limejump Energy Limited | 21 | 2024-12 |
| Lincs Wind Farm Limited | 21 | 2025-12 |
| London Power Networks PLC | 20 | 2026-03 |
| Londonenergy Ltd | 21 | 2019-06 |
| Lynemouth Power Limited | 52 | 2020-12 |
| Lynn Wind Farm Limited | 12 | 2025-12 |
| Marchwood Power Limited | 18 | 2025-12 |
| Medway Power Limited | 27 | 2025-09 |
| Mercia Waste Management Limited | 24 | 2025-12 |
| Mgt Teesside Limited | 23 | 2026-03 |
| Moyle Interconnector Limited | 22 | 2026-03 |
| National Grid Electricity Transmission PLC | 30 | 2026-03 |
| National Grid Gas PLC | 31 | 2025-03 |
| National Grid Grain Lng Limited | 26 | 2025-09 |
| National Grid Ifa 2 Limited | 28 | 2026-03 |
| National Grid Interconnectors Limited | 29 | 2026-03 |
| National Grid Metering Limited | 24 | 2025-03 |
| National Grid North Sea Link Limited | 27 | 2026-03 |
| Norrington Solar Farm Limited | 24 | 2021-12 |
| Northern Ireland Electricity Networks Limited | 39 | 2025-12 |
| Northern Powergrid (Northeast) Limited | 27 | 2025-12 |
| Northern Powergrid (Yorkshire) PLC | 22 | 2025-12 |
| Npower Commercial Gas Limited | 26 | 2025-12 |
| Npower Direct Limited | 26 | 2025-12 |
| Octopus Energy Limited | 13 | 2025-10 |
| Opus Energy (Corporate) Limited | 31 | 2025-12 |
| Opus Energy Limited | 48 | 2025-12 |
| Opus Energy Renewables Limited | 12 | 2025-12 |
| Opus Gas Supply Limited | 43 | 2024-12 |
| Opw Holdco Limited | 29 | 2025-12 |
| Ormonde Energy Limited | 51 | 2024-12 |
| Orsted Power (UK) Limited | 44 | 2025-12 |
| Orsted Race Bank (Holding) Limited | 28 | 2025-12 |
| Orsted Sales (UK) Limited | 30 | 2024-06 |
| Orsted West of Duddon Sands (UK) Limited | 40 | 2025-12 |
| Ovo (S) Electricity Limited | 21 | 2022-06 |
| Pen Y Cymoedd Wind Farm Limited | 35 | 2024-12 |
| Phoenix Natural Gas Limited | 31 | 2026-06 |
| Power Ni Energy Limited | 12 | 2026-03 |
| Power4all Limited | 8 | 2023-12 |
| Px Limited | 40 | 2025-09 |
| Race Bank Wind Farm Limited | 20 | 2025-12 |
| Rampion Offshore Wind Limited | 15 | 2025-12 |
| Refood UK Limited | 43 | 2025-12 |
| Regent Gas Limited | 24 | 2026-03 |
| Renewable Transport Fuel Services Limited | 16 | 2025-03 |
| Rhyl Flats Wind Farm Limited | 31 | 2025-12 |
| Rowan Onshore Windfarms Limited | 56 | 2025-12 |
| Rwe Generation UK PLC | 35 | 2025-12 |
| Rwe Markinch Limited | 44 | 2025-12 |
| Rwe Renewables UK Robin Rigg East Limited | 33 | 2021-06 |
| Saltend Cogeneration Company Limited | 32 | 2024-12 |
| Scira Offshore Energy Limited | 30 | 2025-12 |
| Scotland Gas Networks PLC | 14 | 2026-03 |
| Scottish Hydro Electric Power Distribution PLC | 25 | 2026-03 |
| Scottish Hydro Electric Transmission PLC | 24 | 2026-03 |
| Scottishpower Energy Management Limited | 18 | 2025-12 |
| Scottishpower Energy Retail Limited | 25 | 2025-12 |
| Scottishpower Generation Limited | 32 | 2025-12 |
| Scottishpower Renewable Energy Limited | 6 | 2018-12 |
| Scottishpower Renewables (UK) Limited | 29 | 2025-12 |
| Scottishpower Renewables (Wods) Limited | 21 | 2025-12 |
| Seabank Power Limited | 25 | 2026-06 |
| Seagreen Wind Energy Limited | 21 | 2026-03 |
| Severn Power Limited | 11 | 2020-08 |
| Severn Waste Services Limited | 28 | 2024-12 |
| Shell Energy Europe Limited | 13 | 2025-12 |
| Smartestenergy Limited | 15 | 2026-03 |
| Sonatrach Gas Marketing UK Limited | 13 | 2025-12 |
| South Eastern Power Networks PLC | 5 | 2026-03 |
| South Hook Lng Terminal Company Ltd. | 25 | 2025-12 |
| Southern Electric Gas Limited | 18 | 2023-06 |
| Southern Electric Power Distribution PLC | 23 | 2026-03 |
| Southern Gas Networks PLC | 14 | 2026-03 |
| Sp Distribution PLC | 29 | 2025-12 |
| Sp Manweb PLC | 31 | 2025-12 |
| Sp Transmission PLC | 34 | 2025-12 |
| Sse Airtricity Energy Supply (Ni) Limited | 16 | 2026-03 |
| Sse Airtricity Gas Supply (Ni) Limited | 20 | 2026-03 |
| Sse Energy Supply Limited | 23 | 2026-03 |
| Sse Epm Limited | 20 | 2026-03 |
| Sse Generation Limited | 25 | 2026-03 |
| Sse Hornsea Limited | 27 | 2026-03 |
| Sse Renewables Services (UK) Limited | 23 | 2026-03 |
| Sse Renewables Walney (UK) Limited | 22 | 2020-03 |
| Sse Thermal Energy Operations Limited | 27 | 2026-03 |
| Sse Thermal Generation (Scotland) Limited | 25 | 2026-03 |
| Sse Utility Solutions Limited | 31 | 2026-03 |
| Storengy UK Limited | 27 | 2025-12 |
| Stronelairg Wind Farm Limited | 20 | 2026-03 |
| Sutton Bridge Power Generation | 20 | 2020-08 |
| Teesside Windfarm Limited | 46 | 2025-06 |
| Thanet Offshore Wind Limited | 34 | 2024-12 |
| The Freedom Group of Companies Ltd. | 24 | 2026-02 |
| The Renewable Energy Company Limited | 23 | 2019-04 |
| Total Gas & Power Limited | 14 | 2025-12 |
| Triton Knoll Offshore Wind Farm Limited | 29 | 2025-12 |
| UK Power Networks (Operations) Limited | 18 | 2026-03 |
| UK Power Networks Services (Contracting) Limited | 30 | 2026-03 |
| Uniper UK Limited | 56 | 2023-12 |
| Utilyx Limited | 39 | 2020-03 |
| Vattenfall Wind Power Ltd | 35 | 2024-12 |
| Veolia Energy & Utility Services UK PLC | 41 | 2025-12 |
| Viridian Energy Supply Limited | 40 | 2022-03 |
| Viridor Dunbar Waste Services Limited | 0 | 2026-03 |
| Vital Energi Utilities Limited | 30 | 2025-12 |
| Vpi Holding Limited | 29 | 2025-12 |
| Wales & West Utilities Limited | 34 | 2026-03 |
| Walney (UK) Offshore Windfarms Limited | 23 | 2025-12 |
| Westermost Rough Limited | 20 | 2025-12 |
| Western Power Distribution (East Midlands) PLC | 21 | 2026-03 |
| Western Power Distribution (South Wales) PLC | 21 | 2026-03 |
| Western Power Distribution (South West) PLC | 18 | 2026-03 |
| Western Power Distribution (West Midlands) PLC | 21 | 2026-03 |
| Winnington Chp Limited | 58 | 2026-03 |
| Wmr Jv Investco Limited | 19 | 2026-03 |
| Wood Transmission and Distribution Limited | 57 | 2025-06 |