| Greenx Ltd | Feltham | 2022 |
| Greeny Assets SPV Ltd | Stratford Upon Avon | 2023 |
| Greg Sinclair Cooling Ltd | Wokingham | 2021 |
| Gremista Energy Limited | Shetland | 2023 |
| Gren CHP (Nottingham) Limited | London | 2015 |
| Gren CHP (Sheff) Limited | London | 2014 |
| Grendon Lakes Storage Limited | London | 2021 |
| Grendon Storage Limited | London | 2017 |
| GREP1 Limited | London | 2006 |
| Gresham House Energy Storage Holdings Limited | London | 2020 |
| Gresham House Energy Storage Solutions Limited | London | 2022 |
| Gresham House Solar Distribution Designated Member 1 Limited | London | 2015 |
| Gresham House Solar Distribution Designated Member 2 Limited | London | 2015 |
| Gresham House Wind Energy 1 PLC | Witney | 2019 |
| Gresham House Windfarms General Partner 3 Limited | London | 2015 |
| Gresham Solar Ltd | London | 2022 |
| Greshdown Energy Limited | London | 2011 |
| Gresley Power Ltd | Warrington | 2019 |
| Greta IV Limited | Kingswood, Aylesbury, | 2022 |
| Gretna Grid Services Limited | London | 2020 |
| Gretton Solar Farm Limited | Bristol | 2013 |
| Greviss EV Solutions Ltd | Sutton Coldfield | 2022 |
| Greylion Limited | Goole | 2014 |
| Greys Hall Power Limited | Warrington | 2016 |
| Greystone Capital Limited | Pickering | 2024 |
| Greystone Knowe Wind Farm Limited | Maidenhead | 2017 |
| GRI Energy Co Limited | Blairgowrie | 2016 |
| Grid Comm NE Limited | Leek | 2014 |
| Grid Denki Limited | London | 2025 |
| Grid Energizer Ltd | Rickmansworth | 2017 |
| Grid Engineering Services Limited | Wallasey | 2025 |
| Grid Green Limited | Newcastle | 2022 |
| Grid Line Power Networks Ltd | Borehamwood | 2025 |
| Grid Resilience UK Ltd | Nottingham | 2018 |
| Grid Stability Services Ltd | Cheltenham | 2026 |
| Grid System Engineering Ltd | Stafford | 2025 |
| Gridcodepower Ltd | Upper Norwood | 2016 |
| Gridforce Solutions Ltd | Carluke | 2026 |
| Gridpay Networks Ltd | Southampton | 2025 |
| Gridreserve Ltd | London | 2017 |
| Gridscout Ltd | Southwick | 2025 |
| Gridserve Cornish Solar Ltd | Swindon | 2022 |
| Gridserve EH Ltd | Swindon | 2021 |
| Gridserve Ehgv Limited | Swindon | 2023 |
| Gridserve Emea Depc Ltd | Swindon | 2010 |
| Gridserve Sun to Wheel Ltd | Swindon | 2022 |
| Gridserve Sunway Ltd | Swindon | 2023 |
| Gridserve Sustainable Energy Limited | Swindon | 2017 |
| Gridserve UK OMM Ltd | Swindon | 2017 |
| Gridserve UK Projects Ltd | Swindon | 2015 |
| Gridserve WBC Limited | Swindon | 2018 |
| Gridsource (Woburn RD) Limited | London | 2020 |
| Gridsource Limited | Henlow | 2015 |
| Gridtec Limited | Leeds | 2022 |
| Gridtech Innovations UK Limited | London | 2023 |
| Gridzero Power Corporation UK Limited | London | 2018 |
| Grieve Electrics Limited | Londonderry | 2020 |
| Griffin Electrical Group Limited | Jarrow | 2024 |
| Griffin Energy Limited | Halifax | 2015 |
| Griffin Wind Farm Limited | Perth | 2003 |
| Grigg Brothers Ltd | Launceston | 2013 |
| Grimethorpe Renewable Energy Limited | Reading | 2022 |
| Grimsargh Solar Limited | Reading | 2011 |
| Grimsetter 2024 Ltd | Kirkwall | 2025 |
| Grimsetter Limited | Kirkwall | 2013 |
| Grissan Carnside Ltd | Girvan | 2016 |
| Grissan Carrick Limited | Girvan | 2013 |
| Grissan Coreside Limited | Girvan | 2018 |
| Grissan Portside Limited | Girvan | 2015 |
| Grissan Production Limited | Girvan | 2025 |
| Grissan Riverside Limited | Girvan | 2013 |
| GRM Nexus Ltd | Watford | 2026 |
| GRM Power House Ltd | Watford | 2025 |
| GRM Power Ltd | Watford | 2025 |
| GRM Quest Ltd | Gourdon | 2019 |
| Gronan Wind Farm Limited | Cookstown | 2007 |
| Grosvenor Green GAS Limited | Chester | 2022 |
| Ground Electrical Ltd | Banbridge | 2018 |
| Ground Solar Ltd | Diss | 2022 |
| Grounded Solar Ltd | Radstock | 2013 |
| Groundswell Developments Ltd | Abertawe | 2026 |
| Group R.S. Ltd | London | 2014 |
| Group Utilities Limited | Macclesfield | 2013 |
| Grove Dairy Renewables Ltd | Castlederg | 2024 |
| Grove Farm Solar Farm Limited | London | 2014 |
| Grove Lough Energy Limited | Enniskillen | 2013 |
| Grovebell Contractors Limited | London | 2015 |
| Grovehall Renewable Services Limited | Londonderry | 2019 |
| GRP Energy Limited | London | 2024 |
| Gruggandoo Wind Farm Ltd | Lisburn | 2016 |
| Grwp Hercian CYF | Llanymynech | 2019 |
| GS Hvac Installations Ltd | Leicester | 2022 |
| GS10 Energy Storage Limited | London | 2020 |
| GSC SPV Limited | Liverpool | 2023 |
| Gset Go Limited | London | 2025 |
| Gsii Arkwright 1 C.I.C. | London | 2015 |
| Gsii Arkwright Solar Limited | London | 2015 |
| Gsii Arnawood Limited | London | 2016 |
| Gsii Aston Clinton Solar Farm Limited | Hove | 2013 |
| Gsii Belper Limited | Hove | 2015 |