| Gibair Limited | Birmingham | 2021 |
| Gibsley WT Limited | Motherwell | 2014 |
| Gibson Climpy Limited | Forth | 2012 |
| Gibson Farm Solar Limited | London | 2015 |
| Gibson Heathland Limited | Forth | 2012 |
| Gibson Power Limited | Banbridge | 2023 |
| Gibson Specialist Technical Services Limited | Bridgend | 2008 |
| Gigabox Developments Limited | Mirfield | 2018 |
| Gigabox NO 5 Limited | Mirfield | 2021 |
| Gigenergy RRD Limited | Northampton | 2021 |
| Gigha Renewable Energy Limited | Isle Of Gigha | 2004 |
| Gigha Trading and Renewables Limited | Isle Of Gigha | 2012 |
| Gilfach Renewable Energy Limited | London | 2011 |
| Gilford Hydro Ltd | Craigavon | 2014 |
| Gilfresh AD | Loughgall | 2021 |
| Gilkes Energy (Ederline Hydro) Limited | Edinburgh | 2012 |
| Gillman Biogas Limited | London | 2017 |
| Gillshill GAS and Plumbing Ltd | Hull | 2024 |
| Gilmerton Power Limited | London | 2025 |
| Ginnes Limited | Huntly | 2016 |
| Gino Gineli Ltd | London | 2021 |
| Gipps Energy Limited | London | 2017 |
| Girkk Limited | Blackburn | 2018 |
| Girl Power Energy Limited | Hatfield | 2024 |
| GJM Power Limited | Irvine | 2022 |
| GK Heating Solutions Ltd | Hounslow | 2022 |
| Gkcooling Solutions Ltd | Aylesbury | 2017 |
| GL Electrical Services Ltd | Middlesbrough | 2016 |
| Glac Power Ltd | Newry | 2014 |
| Glacier Air Conditioning Ltd | Kidlington | 2021 |
| Gladsmuir Holdings Limited | Bristol | 2025 |
| Gladsmuir Resource Recovery Limited | Bristol | 2025 |
| Gladsmuir Wind Farm Limited | Huddersfield | 2026 |
| Glamorgan Eco Energy Limited | Neath | 2023 |
| Glamorgan Solar 1 Ltd | London | 2021 |
| Glan Conwy Osprey Ltd | Reigate | 2017 |
| Glanant CYF | Carmarthen | 2011 |
| Glas 1 Limited | London | 2021 |
| Glasa Wind Farm Limited | Maidenhead | 2022 |
| Glasgow Energy Management Ltd | Glasgow | 2026 |
| Glasgow GAS Engineers Ltd | Glasgow | 2024 |
| Glass Leaf Power Limited | London | 2015 |
| Glass Moor II Windfarm Limited | Houghton Le Spring | 2003 |
| Glassenbury Battery Storage Limited | London | 2016 |
| Glassfield Road Solar Limited | Liverpool | 2025 |
| Glasshouse Generation Limited | London | 2014 |
| Glasvaar Limited | Edinburgh | 2021 |
| Gleann Dubhlinn Hydro Limited | St. Albans | 2016 |
| Gleann NAM Fiadh Hydro Ltd | Perth | 2011 |
| Gleaston Solar and Battery Storage Limited | Cheltenham | 2023 |
| Glebe Farm AD Limited | Carlisle | 2014 |
| Glebe Farm Energy Limited | Exeter | 2024 |
| Glebe Farm Solar Limited | Liverpool | 2023 |
| Glebe Farm SPV Limited | London | 2014 |
| Gledsgreen Energy C.I.C. | Banff | 2015 |
| Glen Burn Hydro Limited | Dumfries | 2014 |
| Glen Creran Hydro Limited | Stirling | 2018 |
| Glen Earrach Energy Limited | Edinburgh | 2023 |
| Glen Hydro Chesthill Limited | Glasgow | 2014 |
| Glen Hydro Fassfern Limited | Glasgow | 2014 |
| Glen Hydro Kinlochewe Limited | Glasgow | 2014 |
| Glen Hydro Ledcharrie Limited | Glasgow | 2014 |
| Glen Hydro Loch EIL Limited | Glasgow | 2014 |
| Glen Hydro Lochrosque Limited | Glasgow | 2014 |
| Glen Kinglas Hydro Ltd. | Argyll | 2002 |
| Glen Lednock Wind Farm Limited | London | 2022 |
| Glen LYN Generations Limited | Lynmouth | 1985 |
| Glen Mhor Esco Ltd | Inverness | 2019 |
| Glen Quoich Grid Limited | Blair Atholl | 2014 |
| Glen Quoich Hydro Limited | Blair Atholl | 2010 |
| Glen Quoich PSH Ltd | Blair Atholl | 2025 |
| Glen Righ Hydro Limited | Wimborne | 2014 |
| Glen Ullinish WF 2 Ltd | Motherwell | 2020 |
| Glen Ullinish WF Limited | Motherwell | 2010 |
| Glen Water Wind Farm Limited | Houghton-Le-Spring | 2023 |
| Glenample Hydro Electric Company Limited | Roslin | 2020 |
| Glenbervie Wind Ltd | Edinburgh | 2011 |
| Glenburnie Energy Limited | London | 2024 |
| Glenchamber Wind Energy Limited | Kings Langley | 2014 |
| Glendevon Energy Storage Limited | London | 2021 |
| Glendevon Estate Limited | By Dollar | 1941 |
| Glendoe Limited | Troon | 2012 |
| Glendoe Storage Limited | London | 2022 |
| Glendona Bioenergy Ltd | Craigavon | 2012 |
| Glendye Wind Farm Limited | Maidenhead | 2014 |
| Glenfiddich West Limited | Ringwood | 2023 |
| Glenfinnart Hydro Ltd | Dunoon | 2015 |
| Glengen Ltd | Omagh | 2012 |
| Glenglass Hydro Limited | Ross-Shire | 1996 |
| Glengolly Bess Ltd | Kilwinning | 2024 |
| Glenhead Wind Farm Limited | Glasgow | 2012 |
| Glenheath V1 Limited | Stoke On Trent | 2023 |
| Glenhoy Energy Limited | Augher | 2016 |
| Glenkerie Extension Wind Farm Limited | Milnthorpe | 2013 |
| Glenkerie Wind Farm Limited | London | 2008 |
| Glenlark Wind Farm Limited | Lisburn | 2021 |
| Glenmore Generation Limited | Belfast | 2015 |
| Glenmoriston Electric Company Limited | London | 2019 |
| Glenmuckloch Pumped Storage Hydro Limited | Edinburgh | 2015 |
| Glenmuckloch Renewable Energy Limited | Edinburgh | 2014 |