| Benmore Hydro Limited | Dundee | 2014 |
| Bennettcablesolutions Ltd | London | 2026 |
| Bennetts Electrical Services Limited | Salisbury | 2015 |
| Bennetts Renewables Limited | Worcester | 2019 |
| Benson Hydro Limited | Wallingford | 2011 |
| Bentham Solar Farm Limited | Hove | 2013 |
| Benthead Solar Limited | Edinburgh | 2021 |
| Benthead Wind Farm Limited | Glasgow | 2012 |
| Bentwaters Facilities Limited | Rendlesham | 2004 |
| Benzies Renewable Power Ltd. | Turriff | 2008 |
| Berden Solar Limited | Shepton Mallet | 2017 |
| Berk and BRO Ltd | Letchworth Garden City | 2025 |
| Berkshire Air Conditioning Ltd | Bracknell | 2023 |
| Berkshire EV Solutions Ltd | Slough | 2025 |
| Berkshire GAS Service Limited | Ascot | 2011 |
| Berkshire Solar Solutions Limited | Sandhurst | 2025 |
| Berkswell Battery Storage Limited | London | 2023 |
| Berkswell Energy Park Limited | London | 2022 |
| Berkswell Holding UK Limited | London | 2025 |
| Bernard Matthews Green Energy Halesworth Limited | London | 2008 |
| Bernard Matthews Green Energy Pickenham Limited | London | 2008 |
| Bernard Matthews Green Energy Weston Limited | London | 2008 |
| Bernardo & Son's Ltd | Milton Keynes | 2020 |
| Berry Burn Wind Farm Limited | London | 2002 |
| Berry Court Energy Storage Limited | Reading | 2022 |
| Berryhill Solar Farm Limited | Edinburgh | 2020 |
| Berryhill Trading Company Ltd | By Dundee | 2017 |
| Bersham Colliery Limited | Ellesmere Port | 2023 |
| Berthllwyd Solar Project Limited | Hove | 2014 |
| Berwick Bank a Limited | Reading | 2010 |
| Berwick Bank B Limited | Reading | 2022 |
| Berwick Bank C Limited | Reading | 2010 |
| Berwick Bank Holdings a Limited | Reading | 2010 |
| Berwick Bank Holdings B Limited | Reading | 2022 |
| Berwick Bank Holdings C Limited | Reading | 2010 |
| Berwick Bank Wind Farm Limited | Perth | 2022 |
| Berwick Community Solar Energy Limited | Berwick Upon Tweed | 2012 |
| Berwick Core Ltd | Berwick-Upon-Tweed | 2008 |
| Berwick Renewables DX Limited | Derby | 2024 |
| Berwick Renewables TX Limited | Derby | 2024 |
| Berwick Solar Park Limited | London | 2012 |
| Berwyn Hydro Limited | Manea | 2005 |
| Beryl Street Generation Limited | Greenock | 2017 |
| Bespoke Climate Solutions Ltd | Manchester | 2026 |
| Bespoke Community Energy C.I.C. | Edinburgh | 2020 |
| Bespoke Leisure Living Limited | York | 2004 |
| Bespoke Ventilation Ltd | Wantage | 2011 |
| Bespoke-Electrical-Uk Limited | Redcar | 2019 |
| Bess 1 Limited | Doncaster | 2026 |
| Bess Aylesford Limited | London | 2016 |
| Bess Claredown Limited | London | 2016 |
| Bess ENG 1 Ltd | London | 2025 |
| Bess Foundation | London | 2026 |
| Bess Hill Farm Limited | London | 2017 |
| Bess K Barn Limited | London | 2017 |
| Bess Leys Limited | London | 2017 |
| Bess Oxcroft Limited | London | 2017 |
| Bess Platform Limited | London | 2026 |
| Bess Poplars Limited | London | 2017 |
| Bess Willows Limited | London | 2017 |
| Best Air Commercial & Domestic Ltd | Bedford | 2021 |
| Best Business Utility Ltd | London | 2022 |
| Best Choice Utilities Limited | Epsom | 2020 |
| Best League London Utilities Ltd | London | 2024 |
| Best Telecom Ltd | Cardiff | 2019 |
| Best Utility Ltd | Cardiff | 2019 |
| Best Wind UK 1 Limited | Caterham | 2015 |
| Beta Southmoor Ltd | London | 2019 |
| Bethel Energy Ltd | London | 2025 |
| Betingau Solar Limited | Gatwick | 2013 |
| Betta Tech Air Conditioning Ltd | Milton Keynes | 2024 |
| Better Billing Ltd | Houghton Le Spring | 2016 |
| Better Cooling Services Ltd | Glasgow | 2020 |
| Bettyhill Wind Energy Limited | Aberdeen | 2010 |
| Beverley Bioenergy Ltd | Liverpool | 2026 |
| Beverly Energy Ltd | Birmingham | 2025 |
| Bewiseutilites Ltd | Stoke-On-Trent | 2015 |
| Bexley Green Energy Centre Ltd | Faversham | 2023 |
| Beyond Green Group Ltd | London | 2025 |
| Beys UK Consultancy Limited | London | 2019 |
| Beyside Limited | Girvan | 2017 |
| BF13A TF Solar Limited | Bristol | 2021 |
| BF16D BHF Solar Limited | Bristol | 2021 |
| BF27 BF Solar Limited | Bristol | 2021 |
| BF31 WHF Solar Limited | Bristol | 2021 |
| BF33C LHF Solar Limited | Bristol | 2021 |
| BF33E BHF Solar Limited | Bristol | 2021 |
| BF58 Hunts Airfield Solar Ltd | Bristol | 2022 |
| BF78 GH Bess Limited | Bristol | 2023 |
| BG Commercial Energy Ltd | St Helens | 2025 |
| BG GAS Services Limited | London | 1997 |
| BG Umbra Limited | Morpeth | 2020 |
| BGI Trading Limited | London | 2017 |
| BGS 102 Yorkley Solar Park Limited | Lydney | 2013 |
| BGS 103 Hurst Solar Park Limited | Lydney | 2013 |
| BGS 104 Sedbury Solar Park Limited | Lydney | 2013 |
| BH Electrical (Essex) Limited | Basildon | 2017 |
| BHA Enterprise Ltd | Berwickshire | 2002 |
| Bharat Hydrogen Initiative Ltd | London | 2025 |
| BHI Stores Ltd | Cookstown | 2016 |