| Limejump Virtual 14 Limited | Manchester | 2018 |
| Limejump Virtual 15 Limited | Manchester | 2018 |
| Limekilns Energy Limited | Dunbar | 2024 |
| Limelight Energy Limited | Stafford | 2015 |
| Limes Farm Solar Park Limited | London | 2023 |
| Limitless Electrical SW Ltd | Bridgend | 2024 |
| Linc Solar Ltd | Worksop | 2026 |
| Lincoln Skegness Solar Farm Limited | Reading | 2014 |
| Lincoln W Energy Ltd | Manchester | 2024 |
| Lincolnshire Energy Development Limited | Lincoln | 2011 |
| Lincs Wind Farm Limited | Aberdeen | 2000 |
| Lindridge Solar Limited | London | 2015 |
| Lindsey Energy (Lincolnshire) Limited | Sleaford | 2017 |
| Linehan Mechanical and Electrical Limited | Langley Nr Hitchin | 2014 |
| Linell Renewables Limited | Johnstone | 2014 |
| Linergy Power Limited | Co Tyrone | 2008 |
| Links Solar Farm Limited | London | 2020 |
| Linton Falls Hydroelectric Power Company Limited | Harrogate | 2010 |
| Linton Hydro Ltd | Totnes | 2016 |
| Lion Air Conditioning Ltd | Runcorn | 2019 |
| Lions Air CON Ltd | Ilford | 2025 |
| Lisahoppin Wind Limited | Omagh | 2014 |
| Lisard Renewables Ltd | Castlederg | 2011 |
| Lisburn Energy Ltd | Belfast | 2024 |
| Lisburn Solar Limited | Belfast | 2015 |
| Liscloon Farm Ltd | Strabane | 2012 |
| Liskeeran Donegal Wind Ltd | Cookstown | 2016 |
| Lisleen Energy Limited | Belfast | 2015 |
| Lisna Limited | Newtownstewart | 2017 |
| Lisnabann Power Services Ltd | Ballymena | 2011 |
| Lisnagreen Energy Ltd | Ballymena | 2013 |
| Lisnoo Power Ltd | Belfast | 2014 |
| Lissett Airfield Wind Farm Limited | London | 2007 |
| Lister Battery Ltd | London | 2020 |
| Lithium Grid Limited | Welwyn Garden City | 2026 |
| Little Bear Solar Limited | Bristol | 2016 |
| Little Becks Renewables Limited | Shepton Mallet | 2025 |
| Little Cheyne Court Wind Farm Limited | Swindon | 2005 |
| Little Crow Renewables Limited | Somerset | 2018 |
| Little Fluffy Dog Ltd. | Covent Garden | 2024 |
| Little Gala Windfarm Limited | Bellshill | 2020 |
| Little Irchester Solar Limited | London | 2016 |
| Little Kelham Utilities Ltd | Bradford | 2014 |
| Little Laver Renewables Limited | Shepton Mallet | 2025 |
| Little Lever GAS Services Ltd | Bolton | 2005 |
| Little Morton Limited | London | 2012 |
| Little Ness Energy Limited | London | 2024 |
| Little Oak Biogas Ltd | Guildford | 2023 |
| Little Raith Wind Farm Limited | London | 2002 |
| Little South Clean Energy Limited | London | 2022 |
| Little Standard Hill Power Limited | London | 2025 |
| Little Staughton Airfield Solar Limited | London | 2010 |
| Little Sutton Energy Company Limited | London | 2011 |
| Little T Solar Limited | London | 2012 |
| Littlebourne Solar Farm Limited | Gatwick | 2013 |
| Littlebrook Green Energy Centre Ltd | Faversham | 2022 |
| Littledale Hall Farm Limited | Lancaster | 2011 |
| Littlegill EV Ltd | Motherwell | 2025 |
| Littleton Burn Ltd | Auchterarder | 2018 |
| Littleton Pastures Solar Limited | Reading | 2020 |
| Littleton Solar Farm Limited | London | 2013 |
| Littlewood Farm Solar Limited | Hove | 2013 |
| Littlewood Solar Limited | London | 2015 |
| Litton Energy Limited | Bakewell | 2017 |
| Live Natural Ltd | London | 2019 |
| Live Wire Solutions Ltd | Malvern | 2025 |
| Livenergy Ltd | London | 2017 |
| Liverton 2014 Limited | Exeter | 2014 |
| Liverton Solar Ltd | Exeter | 2014 |
| Livewire TS Ltd | Liverpool | 2026 |
| Livewire TSG Ltd | Skelmersdale | 2025 |
| Living Bio-Power Limited | London | 2007 |
| Living Energy SPV 99 Limited | Aylesbury | 2015 |
| Living Power Limited | London | 2006 |
| Livos Renewables Limited | London | 2020 |
| LJB Cooling Ltd | Loughton | 2018 |
| Ljll Utilities Ltd | Chester Le Street | 2017 |
| LJM Winds Limited | Roslea | 2013 |
| LK Air CON and Ventilation Ltd | Ramsgate | 2019 |
| LK Energy Services Ltd | Hockley | 2026 |
| LKB Cooling Limited | Billingshurst | 2025 |
| Lklr Renewable Energy Ltd | Stockton-On-Tees | 2020 |
| LL Renewables Limited | Bognor Regis | 2025 |
| Llanbrynmair Energy Limited | Kings Langley | 2024 |
| Llandyfaelog Bess Limited | London | 2024 |
| Llangennech Heating Limited | Llangennech | 2021 |
| Llanwern B.E.S.S. Limited | Nr Cricklade | 2014 |
| Llanwern Solar Assets Limited | Nr Cricklade | 2019 |
| Llanwynno Energy Ltd | Bridgend | 2017 |
| Llanwynno Green Power Limited | Bridgend | 2025 |
| Llay Power Limited | Salford Quays | 2023 |
| LLG Power Distribution Limited | Middlesbrough | 2022 |
| Lloyd Thomas Environmental Ltd | Llanybydder | 2016 |
| Lluest Y Gwynt Wind Farm Limited | London | 2018 |
| Llwyn Celynnen CYF | Usk | 2012 |
| Llwyn Derw Battery Storage Limited | Stonehouse | 2022 |
| Llwyndyrus Solar Farm Limited | Cheltenham | 2015 |
| Llyn Lort Energy Park Limited | Cardiff | 2021 |
| Llyn Lort II Energy Park Limited | Cardiff | 2022 |
| LMB Electrical Services Limited | Cleckheaton | 2012 |