| DR GAS Limited | Ilford | 2018 |
| Dracus Energy Supply Ltd | London | 2020 |
| Draffan Renewables Limited | Lesmahagow | 2025 |
| Dragon Air Conditioning Limited | South Glamorgan | 2003 |
| Dragon Energy Limited | Milford Haven | 2004 |
| Dragon Hvac Ltd | Cardiff | 2025 |
| Dragon Hydro Ltd | Huntingdon | 2008 |
| Dragon LNG Limited | Milford Haven | 2002 |
| Dragon Wind Energy (Anglesey) Limited | Holyhead | 2015 |
| Dragons Lane Battery Storage Limited | London | 2023 |
| Drake Electrical Services Ltd | Worthing | 2020 |
| Drakelow Green Energy Limited | Faversham | 2021 |
| Drakelow NG Limited | Cheltenham | 2023 |
| Drakelow Solar Limited | Faversham | 2013 |
| Drakes Renewables Limited | Harpenden | 2012 |
| Drapers Farm Limited | London | 2011 |
| Drapers Gardens 2011 Limited | London | 2010 |
| Drapersfield Hydro Ltd | Magherafelt | 2025 |
| Drawroof Limited | Tyne & Wear | 1972 |
| Drax Bess EK Limited | North Yorkshire | 2023 |
| Drax Bess Marfleet Limited | Selby | 2020 |
| Drax Bess Neilston Limited | Selby | 2022 |
| Drax Energy Solutions Limited | Selby | 2006 |
| Drax Power Limited | Selby | 2003 |
| Drax Pumped Storage Limited | Selby | 2008 |
| Drax River Hydro Limited | North Yorkshire | 2006 |
| Drayton Mead Solar Limited | London | 2015 |
| DRB Electrical Ltd | Benfleet | 2012 |
| DRD SPV Bess 2 Limited | London | 2024 |
| DRD SPV Solar 1 Limited | London | 2024 |
| DRD SPV Solar 2 Limited | London | 2024 |
| Drd-Hanwha Development Company Limited | London | 2024 |
| Dreachmhor Wind Farm Limited | Kings Langley | 2013 |
| Dreadnought Utilities Ltd | Widnes | 2022 |
| Dream Energy Ltd | London | 2016 |
| Dredge Electrical Ltd | Rochdale | 2026 |
| Dredgeman Energy Limited | London | 2015 |
| Drefelin Wynt Limited | Whitland | 2013 |
| Dren Electrical Ltd | Hull | 2016 |
| Drift Energy Ltd | Bath | 2021 |
| Drim LEE Limited | Edinburgh | 2012 |
| Drin Wind Limited | Belfast | 2016 |
| Drinkstone Energy Centre Limited | Essex | 2021 |
| DRM Plumbing and Electrical Ltd | Swadlincote | 2019 |
| DRO Electrics Limited | Leeds | 2023 |
| Drointon Solar Farm Limited | Colchester | 2022 |
| Droitwich Peak Energy Limited | London | 2019 |
| Dromleena Wind Energy Limited | London | 2024 |
| Drone Hill Wind Farm Limited | Edinburgh | 2004 |
| Drone Power Ltd | Liverpool | 2020 |
| Drove Lane Solar Park C.I.C. | London | 2014 |
| Drover Lane Solar Farm Limited | London | 2019 |
| Druim Leathann Windfarm Limited | Edinburgh | 2012 |
| Drum Energy Ltd | Belfast | 2013 |
| Drumack Wind Ltd | Ballyclare | 2016 |
| Drumanakelly Power Ltd | Larne | 2012 |
| Drumard Wind Limited | Belfast | 2016 |
| Drumbrick Wind Ltd | Cookstown | 2013 |
| Drumclune Renewables Limited | Shepton Mallet | 2025 |
| Drumcraig Wind Limited | Strabane | 2021 |
| Drumcross Generation Limited | Greenock | 2017 |
| Drumduff Extension Ltd | Alloa | 2015 |
| Drumforskie Riding Centre Ltd. | Aberdeen | 2000 |
| Drumhappy Wind Limited | Belfast | 2016 |
| Drumhoney Renewables Limited | Irvinestown | 2024 |
| Drumkee Energy Limited | London | 2019 |
| Drumlee Energy Limited | Ballymoney | 2025 |
| Drumlegagh Wind Ltd | Cookstown | 2014 |
| Drummarnock Wind Farm Limited | Edinburgh | 2020 |
| Drumoig Renewable Energy Limited | Dundee | 2012 |
| Drumore Battery Storage Limited | Bristol | 2024 |
| Drumrack Renewables Ltd | St. Andrews | 2013 |
| Drumrusk Ltd | Belfast | 2016 |
| Drums Wind Limited | Peterhead | 2015 |
| Dry-It-Out Limited | Nuneaton | 2003 |
| Dryair Ltd | Market Rasen | 2020 |
| Dryholme Biogas Limited | Blackpool | 2009 |
| Drym Developments Ltd | Aberdare | 2015 |
| Dryserve Ltd | Wokingham | 2013 |
| DS Commercial Utility Ltd | Monkton | 2017 |
| DS GAS & Heating Services Ltd | London | 2024 |
| DS GAS Utilities Limited | Chelmsford | 2022 |
| DS Wind Energy Limited | Huddersfield | 2013 |
| Dsasres Ltd | London | 2023 |
| DSH Cables & Controls Ltd | Twemlow | 2016 |
| DSO Engineering Ltd | Dunmow | 2025 |
| DSS Heating and Electric Ltd | Ruislip | 2018 |
| DT & JT Services Ltd | Goole | 2017 |
| Dual Meter Systems Limited | Ware | 2018 |
| Duart Energy Limited | Isle Of Mull | 2024 |
| Duarte Energy Ltd | Bodfari | 2015 |
| Duckinfield Solar Limited | London | 2025 |
| Ducklington Solar Limited | Cheltenham | 2020 |
| Duct Depot Ltd | Abingdon | 2025 |
| Duct Services (N.I.) Ltd | Cookstown | 2011 |
| Duct Technologies Limited | Stanmore | 2023 |
| Ductbusters Holdings Limited | Halesowen | 2014 |
| Ductly Ltd | London | 2026 |
| Ductmann Limited | Northampton | 1994 |
| Ductstation Ltd | Diss | 2015 |