| Glenn Conroy Electrical Ltd | Chester | 2025 |
| Glenn K Smith Limited | Choppington | 2018 |
| Glenniston Solar Project Ltd | Birmingham | 2021 |
| Glennon Bros. Energy Ltd | Troon | 2016 |
| Glenquicken ENG. Ltd | Newton Stewart | 2016 |
| Glenrothes Bess Ltd | London | 2021 |
| Glens of Foudland Wind Farm Limited | Kings Langley | 2002 |
| Glensalloch Wind Farm Limited | Edinburgh | 2024 |
| Glentaggart Wind Farm Limited | Milnthorpe | 2011 |
| Glenuig Hydro Power Limited | Edinburgh | 2014 |
| Glenure Estate Limited | Edinburgh | 2017 |
| Glenwherry Wind Limited | Ballymena | 2008 |
| Glesni Cyfyngedig | Corwen | 2015 |
| Glew Enterprises Limited | York | 2013 |
| Glide 2 Limited | Birmingham | 2010 |
| Glide Utilities Limited | Birmingham | 2007 |
| Glinton and Peakirk Energy Community Interest Company | Peterborough | 2015 |
| Global Air Conditioning Ltd | Liverpool | 2022 |
| Global Cooling Limited | Wembley | 2026 |
| Global Cooling Refrigeration Ltd | Darwen | 2022 |
| Global Cooling Solutions Ltd | Ballyclare | 2015 |
| Global Current Energy Solution Group Limited | Luton | 2025 |
| Global Energy (U.K.) Limited | Newquay | 1998 |
| Global Energy Development Limited | London | 2019 |
| Global GAZ Group Ltd | London | 2014 |
| Global Green Energy & Power Corporation Limited | London | 2016 |
| Global Green Generation (DCS) Ltd | London | 2025 |
| Global Greengen Ltd | London | 2016 |
| Global Hvac Ltd | Wakefield | 2017 |
| Global Industria Ltd | Bury St. Edmunds | 2023 |
| Global Mechanical and Renewable Services Ltd | Rochester | 2018 |
| Global Plant Hire Solutions Ltd | London | 2023 |
| Global Power Limited | London | 2016 |
| Global Power Services (U.K.) Limited | St. Helens | 2009 |
| Global Renewable Offshore Wind Ltd | Great Yarmouth | 2025 |
| Global Savora Imaging Ltd | London | 2020 |
| Global Solution Engineering Ltd | London | 2025 |
| Global South Energy Limited | Wembley | 2025 |
| Global Tower Solutions Limited | London | 2016 |
| Global Utilities Marketing Ltd | Romford | 2023 |
| Globe Engineering (Hull) Limited | Leeds | 1949 |
| Globeleq Holdings (Zambia) Limited | London | 2017 |
| Globeleq Nominees Limited | London | 2016 |
| Globell Energy Ltd | Belvedere | 2017 |
| Globovac Ltd | Wellington | 2010 |
| Gloucester Air Conditioning Ltd | Gloucester | 2025 |
| Gloucester Energy Park Limited | London | 2022 |
| Gloucester Railway Carriage & Wagon Company | Bracknell | 1942 |
| Gloucester Wind Limited | London | 2012 |
| Glow Fuels Limited | Girvan | 2017 |
| Glowgear Ltd | Milton Keynes | 2025 |
| Glynllifon Energy Limited | Corwen | 2023 |
| GM Bigrigg Bess Limited | Beverley | 2024 |
| GM Bolehill Solar & Bess Limited | Beverley | 2024 |
| GM Bradley Solar & Bess Limited | Beverley | 2023 |
| GM Carr Farm Solar & Bess Limited | Beverley | 2023 |
| GM Clough Road Bess Ltd | Beverley | 2022 |
| GM Construction (London) Ltd | Kingston Upon Thames | 2013 |
| GM Lewes Bess Limited | Beverley | 2024 |
| GM Peafield Solar & Bess Limited | Beverley | 2023 |
| GM Preston Bess Limited | Beverley | 2022 |
| GM Preston Solar Limited | Beverley | 2022 |
| GM Raymond Brown Solar Limited | Beverley | 2023 |
| GM Scunthorpe Bess Limited | Beverley | 2024 |
| GMA Renewables Ltd | Castell-Nedd | 2026 |
| GMC Controls Ltd | Portsmouth | 2017 |
| GMD Air Conditioning Limited | Royal Arsenal | 2020 |
| GME Project Solutions Ltd | Manchester | 2018 |
| Gmgbatt 1 Limited | London | 2023 |
| GMH Management & Recruitment Consultants Ltd. | Manchester | 2015 |
| GMK London Limited | London | 2024 |
| GMR Group Limited | Wigan | 2020 |
| GMS Heating Limited | Perth | 2014 |
| GN Renewables Ltd | Radstock | 2011 |
| Gnergy Limited | London | 2009 |
| Gnnr Ltd | Edinburgh | 2016 |
| Gnowee Power Limited | Bristol | 2010 |
| Go Air Ltd | London | 2020 |
| Go Electric (CHP) Limited | Newport | 2022 |
| Go Energy Compare Ltd | Bolton | 2021 |
| Go GAS and Power Ltd | Durham | 2017 |
| Go Green Innovations Limited | Doncaster | 2025 |
| Go Green PPA Ltd | Carnforth | 2025 |
| Go H2 Limited | Belfast | 2024 |
| Go Power Norwich Ltd | Norwich | 2025 |
| Go Wind Ltd | North Shields | 2017 |
| Go-Secure Solutions Ltd | Glasgow | 2018 |
| Go-Zero Energy Limited | London | 2025 |
| GO4 Control Ltd | Isleworth | 2018 |
| GO4ENERGY Limited | Woodford Green | 2008 |
| Goacher Refrigeration Ltd | Nottingham | 2018 |
| Goddard Engineering Services Ltd. | Ross Shire | 2005 |
| Goddards Green Solar Limited | Faversham | 2014 |
| Godfrey and Lappage Services Ltd. | Hornchurch | 1999 |
| Godfrey Lappage Group Limited | Hornchurch | 2024 |
| Goeco Renewables Limited | London | 2016 |
| Gofer Limited | Ipswich | 1988 |
| Gofer Power Solutions Ltd | Ipswich | 2011 |
| Gofer Production Services Limited | Ipswich | 2016 |
| Gogreen Energy Supplies Ltd | Dunmow | 2019 |