| Gaia Europe Limited | London | 2019 |
| Gaia Heat (Coeus) Limited | Manchester | 2013 |
| Gaia Heat Limited | Manchester | 2012 |
| Gaia Hire Ltd | Ammanford | 2017 |
| Gaia Power Systems Ltd | London | 2011 |
| Gaineamhach Limited | Glasgow | 2022 |
| Gairloch Estate Limited | Gairloch | 2025 |
| Gairy Hill Wind Farm Limited | Glasgow | 2010 |
| Gajah Singo Rojo Ltd | London | 2025 |
| Galawhistle Extension Wind Farm Limited | Milnthorpe | 2012 |
| Gale Air Limited | Mildenhall | 2024 |
| Galeforce Holdings Limited | London | 2023 |
| Galeforce Investments Limited | Langholm | 2012 |
| Galetech Energy (UK) Limited | Omagh | 2015 |
| Galetech Energy Holdings (UK) Ltd | Omagh | 2025 |
| Galgorm Renewables Limited | Ballymena | 2012 |
| Galileo 01 Limited | Greenside Place | 2022 |
| Galileo 02 Limited | Greenside Place | 2022 |
| Galileo 03 Limited | Cardiff | 2022 |
| Galileo 04 Limited | Greenside Place | 2023 |
| Galileo 05 Limited | Greenside Place | 2023 |
| Galileo 06 Limited | Cardiff | 2023 |
| Galileo 07 Limited | Greenside Place | 2023 |
| Galileo 08 Limited | Cardiff | 2023 |
| Galileo 09 Limited | Cardiff | 2023 |
| Galileo 10 Limited | Greenside Place | 2023 |
| Galileo 11 Limited | Greenside Place | 2023 |
| Galileo 12 Limited | Greenside Place | 2023 |
| Galileo 13 Limited | Greenside Place | 2023 |
| Galileo 14 Limited | Cardiff | 2023 |
| Galileo 15 Limited | Cardiff | 2023 |
| Galileo 16 Limited | Greenside Place | 2023 |
| Galileo 17 Limited | Greenside Place | 2023 |
| Galileo 18 Limited | Greenside Place | 2024 |
| Galileo 19 Limited | Greenside Place | 2024 |
| Galileo 20 Limited | Greenside Place | 2024 |
| Galileo 21 Limited | Greenside Place | 2024 |
| Galileo 22 Limited | Greenside Place | 2024 |
| Galileo 24 Limited | Cardiff | 2024 |
| Galileo 25 Limited | Cardiff | 2024 |
| Galileo 26 Limited | Greenside Place | 2024 |
| Galileo 27 Limited | Greenside Place | 2024 |
| Galileo 28 Limited | Greenside Place | 2024 |
| Galileo Empower (NI) Limited | Belfast | 2023 |
| Galileo Empower Limited | Greenside Place | 2020 |
| Galileo Empower Renewables Limited | Cardiff | 2024 |
| Galileo Empower UK Limited | Greenside Place | 2020 |
| Galileo Empower Wales Limited | Cardiff | 2021 |
| Gallanach Green Generation Limited | Argyll | 2010 |
| Galley Energy Limited | Belfast | 2013 |
| Galloper Wind Farm Limited | Swindon | 2010 |
| Gallow RIG Windfarm Limited | Edinburgh | 1994 |
| Galmark Electrical Ltd | Dartford | 2020 |
| Galson Energy Limited | Isle Of Lewis | 2004 |
| Galsworthy Wind Park Limited | Stroud | 2007 |
| Galton Manor Solar Park Limited | Bristol | 2013 |
| Galtres Energy Limited | Gainsborough | 2018 |
| Galxc Rental Services Ltd | Southampton | 2012 |
| GAM Capital Limited | Beverley | 2015 |
| Gamcap Developments Limited | Beverley | 2024 |
| Gamcap Magnora Development Company Limited | Beverley | 2022 |
| Gamct Electrical Services Ltd | Cowdenbeath | 2022 |
| Gamlingay Community Turbine Ltd | Sandy | 2010 |
| Gamma Umbra Limited | Morpeth | 2020 |
| Gaoirean Hydro Ltd | Leeds | 2017 |
| Gapp Family Properties Limited | Diss | 2025 |
| Garbhaig Hydro Power Company Limited | Lochgilphead | 1985 |
| Garcrogo WF Limited | Motherwell | 2013 |
| Garden Energy Ltd | Alloa | 2021 |
| Gardner Air Services Limited | Cardiff | 1998 |
| Gardrum Farm Wind Energy Limited | Hamilton | 2015 |
| Gareth Suddens Heating Limited | Coventry | 2018 |
| Garganey Sustainable Energy Solutions Limited | London | 2014 |
| Garlaff Energy Limited | Edinburgh | 1999 |
| Garlenick Wind Farm Limited | Warrington | 2011 |
| Garraroosky Wind Ltd | Belfast | 2016 |
| Garreg Fawr Energy Park Limited | Cardiff | 2020 |
| Garrett Management Limited | Petersfield | 2004 |
| Garrick Consulting Ltd | Glasgow | 2006 |
| Garrison Hill Wind Ltd | Cookstown | 2016 |
| Garryheillie Wind Limited | South Uist | 2014 |
| Garstang Wind Direct Limited | Preston | 2009 |
| Garston Power Limited | Bedford | 2014 |
| Garth Fawr Farm Bess Limited | Cheltenham | 2023 |
| Garth Hall Farm Bess Limited | Cheltenham | 2023 |
| Garth Wind Limited | Yell | 2013 |
| Garvagh Energy Supply Limited | Dungannon | 2013 |
| Garvary II Wind Farm Limited | Maidenhead | 2021 |
| Garvary Wind Farm Limited | Maidenhead | 2015 |
| Garvault Hydro Limited | Edinburgh | 2008 |
| Garves Wind Limited | London | 2002 |
| Garvie Hydro Ltd | Edinburgh | 2019 |
| Garvilland Wind Farm Limited | Huddersfield | 2026 |
| Garvinack Solar Farm Limited | Hove | 2014 |
| Gary Squire Electrical Limited | Wells | 2004 |
| Gary Thornhill Electrical Ltd | Windsor | 2019 |
| GAS & Water Solutions (Yorkshire) Ltd | Gateshead | 2022 |
| GAS 2 Electrics Ltd | Croydon | 2017 |
| GAS 4 Wales Limited | Ammanford | 2013 |
| GAS and Power Limited | Manchester | 2015 |