| AMP Solar Limited | London | 2018 |
| Ampah Ltd | London | 2025 |
| Ampcore Electrical Solutions Ltd | London | 2026 |
| Amped Investments Limited | Exeter | 2014 |
| Amper-Uk Limited | Nottingham | 2017 |
| Ampergia Limited | Milton Keynes | 2021 |
| Ampfinity Limited | Cranbrook | 2025 |
| Ampire Electrical Services Limited | London | 2016 |
| Amplify EV Limited | Swindon | 2025 |
| Ampoweruk Ltd | Richmond | 2016 |
| Ampup Ltd | Newtownards | 2025 |
| AMS Air Conditioning Limited | Chelmsford | 2016 |
| Amward Limited | Gainsborough | 2012 |
| AMX Energy Services Limited | Llandudno | 2021 |
| AN Aircon Ltd | Brentford | 2023 |
| AN Avel Braz Energies Limited | London | 2006 |
| AN Muileann CIC | Co Derry | 2008 |
| AN Suidhe Wind Farm Limited | Swindon | 2005 |
| Anaerobic Advantage Limited | London | 2015 |
| Anahorish Renewables Limited | Magherafelt | 2017 |
| Anam NA Mara Limited | London | 2021 |
| Ancala Bioenergy Investco Limited | London | 2019 |
| Ancala Bioenergy Limited | London | 2017 |
| Ancala Bioenergy Midco Limited | London | 2017 |
| Anchor Lane Bess Ltd | London | 2021 |
| Anchor Renewables Ltd | London | 2011 |
| Anchor Well Ltd | Narberth | 2013 |
| Ancleggan 01 Limited | Wimborne | 2025 |
| Ancleggan 02 Limited | Wimborne | 2025 |
| Ancleggan Limited | Wimborne | 2020 |
| Anden Limited | Axminster | 2011 |
| Andershaw Wind Power Limited | London | 2011 |
| Andina Electricidad Limited | Sheffield | 2006 |
| Andina Energies PLC | Sheffield | 2012 |
| Andover Airfield Solar Developments Limited | London | 2013 |
| Andover Solar Park Limited | Andover | 2013 |
| Andrew Martyn Homes Ltd | Tonbridge | 2021 |
| Andrew Tose Ltd | Middlesbrough | 2018 |
| Andromeda Resources Limited | Manchester | 2014 |
| Andros Energy Limited | London | 2017 |
| Anele Energy Power Ltd | London | 2021 |
| Anesco Asset Management Three Limited | Reading | 2013 |
| Anesco Berry Court Limited | Reading | 2014 |
| Anesco MID Devon Limited | Reading | 2011 |
| Anesco Solar Rooftop 1 Limited | Cheltenham | 2015 |
| Anesco South West Limited | Reading | 2011 |
| Anesco Stud Farm Limited | Reading | 2014 |
| Angel Nobel Ltd | London | 2017 |
| Anglesey Energy Limited | Bury St. Edmunds | 2019 |
| Anglesey OIL Limited | Gaerwen | 1982 |
| Anglesey Solar Limited | Hove | 2013 |
| Anglian Electrical Solutions Ltd | Wisbech | 2015 |
| Anglo Panther Power Limited | Thetford | 2023 |
| Anglo Renewables Ltd | Corby | 2020 |
| Angus Biofuels Ltd | Forfar | 2014 |
| ANI Energy Ltd | Truro | 2011 |
| ANI Power Limited | Croydon | 2016 |
| ANK & K Ltd | Brigg | 2018 |
| ANL Offshore Ltd | Scholes | 2020 |
| Annat Burn Hydro Limited | Edinburgh | 2014 |
| Annetech Limited | Bexley | 2011 |
| Anquish Electrical Limited | Southampton | 2016 |
| Anrcorp Limited | London | 2013 |
| Anslow Renewables Limited | Burton-On-Trent | 2019 |
| Antarctica Enterprise Ltd | London | 2020 |
| Antrim Road Energy Limited | Craigavon | 2025 |
| Antrim Wind Energy Ltd | Belfast | 2006 |
| Ants Energy Ltd | London | 2023 |
| Antur CWE CYF | Newtown | 2016 |
| Anua Clean Air UK Limited | Hawick | 2017 |
| Anything Electrical (CJ) Ltd | Bracknell | 2015 |
| AOC ENG UK Limited | Margate | 2025 |
| AOE Windfarm Limited | Aberdeen | 2011 |
| AON GAS Services Limited | Chinnor | 2009 |
| AP Energy Ltd | Boston | 2026 |
| AP Power Services Limited | Gravesend | 2023 |
| AP2L 2405 Briercliffe Energy Storage Ltd | Weybridge | 2024 |
| AP2L 2407 Dobby Rocks Energy Storage Ltd | Weybridge | 2024 |
| APA Environment and Energy PVT Ltd | Stanmore | 2019 |
| Apatura Battery - Project Holding 1 Limited | Altrincham | 2023 |
| Apatura Battery - Project Holding 2 Ltd | Altrincham | 2023 |
| Apatura Battery Ltd | Altrincham | 2022 |
| Apatura DC Project 1 Ltd | Altrincham | 2024 |
| Apatura DC Project 10 Ltd | Altrincham | 2024 |
| Apatura DC Project 2 Ltd | Altrincham | 2024 |
| Apatura DC Project 3 Ltd | Altrincham | 2024 |
| Apatura DC Project 4 Ltd | Altrincham | 2024 |
| Apatura DC Project 5 Ltd | Altrincham | 2024 |
| Apatura DC Project 6 Ltd | Altrincham | 2024 |
| Apatura DC Project 7 Ltd | Altrincham | 2024 |
| Apatura DC Project 8 Ltd | Altrincham | 2024 |
| Apatura DC Project 9 Ltd | Altrincham | 2024 |
| Apatura Direct Power Ltd | Altrincham | 2023 |
| Apatura Hydrogen Ltd | Altrincham | 2022 |
| Apatura International Ltd | Altrincham | 2023 |
| Apatura Ltd | Altrincham | 2022 |
| Apatura Project 20 Ltd | Altrincham | 2024 |
| Apatura Project 21 Ltd | Altrincham | 2024 |
| Apatura Project 22 Ltd | London | 2024 |
| Apatura Project 23 Ltd | Altrincham | 2024 |