| Fulcrum Metering Services Limited | Leeds | 2016 |
| Fulcrum Pipelines Limited | Sheffield | 2006 |
| Fulcrum Power Limited | Norwich | 2013 |
| Fullcircle Energy Ltd | Colchester | 2012 |
| Fuller Air Services Limited | Rochester | 2020 |
| Fuller Electrical Ltd | Bedford | 2015 |
| Fullerton Solarfield Limited | London | 2015 |
| Fullgreen Energysolutions Ltd | Haltwhistle | 2023 |
| Fully Solar Limited | Huddersfield | 2024 |
| Fulscot Power Ltd | Warrington | 2019 |
| Fulwood Electrical Ltd | Preston | 2014 |
| Fundamental Energy Trading Ltd | London | 2015 |
| Furness Property Solutions Limited | Bishop Auckland | 2014 |
| Furnish Renewables Ltd | Fivemiletown | 2016 |
| Furud Solar Ltd | Bristol | 2020 |
| Fury Energy Ltd | Rotherham | 2020 |
| Fury Power Limited | Rotherham | 2020 |
| Fuse Energy Supply Limited | Canary Wharf | 2013 |
| Fuse Energy Supply NI Limited | Ballymena | 2024 |
| Fuse Fenton Lane Limited | Canary Wharf | 2026 |
| Fuse Huthwaite Limited | Canary Wharf | 2026 |
| Fuse Peaker Asset Holdings Limited | Canary Wharf | 2026 |
| Fuse Peaker Assets 1 Limited | Canary Wharf | 2026 |
| Fuse Renewables Limited | Canary Wharf | 2023 |
| Fusion 66 Electrical Limited | Gloucester | 2016 |
| Fusion Biomass Ltd | Southampton | 2019 |
| Fusion Solar & Battery Limited | Port Talbot | 2022 |
| Futura Energies UK Limited | Stallingborough | 2022 |
| Future (Drigg) Ltd | Northampton | 2016 |
| Future (Pennygillam) Limited | Northampton | 2014 |
| Future (Wind GEN) Limited | Belfast | 2011 |
| Future Boilers Ltd | Liverpool | 2015 |
| Future DEV 1 Limited | London | 2024 |
| Future DEV 2 Limited | London | 2016 |
| Future Electric Limited | Wadhurst | 2009 |
| Future Energy Generation Limited | Norwich | 2011 |
| Future Energy Llanwern Limited | London | 2018 |
| Future Green Finance Limited | Horsham | 2011 |
| Future Home Systems Limited | Beverley | 2021 |
| Future Houses and Energy Solutions Ltd | Aylesbury | 2025 |
| Future Maintenance Ltd | London | 2022 |
| Future Point Manchester Limited | Stokesley | 2023 |
| Future Power Enterprises Ltd | London | 2023 |
| Future Renewables Eco Energy Ltd | Edinburgh | 2015 |
| Future Renewables Eco PLC | Glasgow | 2015 |
| Futureflux Energy Solutions Limited | Coventry | 2026 |
| Futurefuel Operations (214) Limited | London | 2017 |
| Futurefuel Operations Limited | London | 2016 |
| Futurefuel Renewables II PLC | London | 2017 |
| Futurefuel Renewables PLC | London | 2016 |
| Futurespectrum Limited | London | 2009 |
| Futurize Solutions Ltd | Basildon | 2023 |
| Futurum (19) Limited | Yarm | 2012 |
| Fuxiona Energy UK Limited | Glastonbury | 2024 |
| FVS Manor Farm Ltd | London | 2022 |
| FVS Westfield Road Ltd | London | 2022 |
| FVW Ltd | Strabane | 2023 |
| FW G&T Wind Holdings Limited | London | 2019 |
| Fwad Limited | Northampton, | 2026 |
| Fyfin Energy Ltd | Omagh | 2017 |
| Fylde Solar Limited | Letchworth Garden City | 2019 |
| Fyne Energy Limited | Isle Of Bute | 2016 |
| Fyrion Energy Limited | London | 2025 |
| Fyronex Commerce Ltd | Coventry | 2026 |
| Fyvie Community Turbines Ltd | Turriff | 2012 |
| G & B Renewables Limited | Milltimber | 2012 |
| G & C Energy Ltd | Barmouth | 2011 |
| G & M Utilities Ltd | Helensburgh | 2021 |
| G & S Sinclair Limited | Latheron | 2014 |
| G & W Refrigeration Limited | Glasgow | 1983 |
| G a Green Energy Limited | Macclesfield | 2022 |
| G B L Solutions Limited | Warrington | 2010 |
| G Debono Electrical Services Ltd | Caerphilly | 2017 |
| G Energy Solar Systems Ltd | London | 2022 |
| G Green GAS Services Ltd | Birmingham | 2014 |
| G Odell Climate Control Ltd | London | 2026 |
| G P Pipelines Limited | Ludow | 2006 |
| G P Quoreenton (Ductwork) Limited | Tring | 2008 |
| G Power Solar Ltd | Whitchurch Rural | 2023 |
| G R Grundy Electrical Ltd | Preston | 2020 |
| G TEK Electrical Solutions Ltd | Liverpool | 2012 |
| G&S Solar Limited | Tunbridge Wells | 2016 |
| G&T Electrical and Property Services Ltd | Maidenhead | 2004 |
| G-Lec Solar Ltd | Bridgend | 2022 |
| G-Mecs Limited | Mansfield | 2012 |
| G. S. GAS Solutions Ltd | Coleford | 2015 |
| G. T. Cylec Limited | Crewe | 2003 |
| G.A.S. Installations Limited | Birmingham | 2006 |
| G.M.G Electrical Innovation Ltd | Blackwood | 2023 |
| G2 Refrigeration & Air Conditioning Ltd. | Glasgow | 2011 |
| G2E Services Ltd | Burntisland | 2019 |
| G2EV Ventures Limited | London | 2025 |
| G8 Plumbing and Heating Limited | Bedford | 2020 |
| G8REAT Power Group Ltd | London | 2025 |
| GA Technologies Ltd | | 2004 |
| GAC Mechanical Services Limited | Horsham | 2010 |
| Gacrux Solar Limited | Bristol | 2021 |
| Gael Wind Partners Ltd. | Glasgow | 2012 |
| Gaelectric Green Energy Limited | Belfast | 2013 |
| Gaelectric Natural Resources Limited | Belfast | 2015 |