| Blaney Power Limited | Enniskillen | 2017 |
| Blantyre Hydro Limited | Gatehouse Of Fleet | 2014 |
| Blantyre Muir Wind Energy Limited | London | 2005 |
| Blarghour Power Company Limited | Perth | 1992 |
| Blarghour Wind Farm Limited | Maidenhead | 2014 |
| Blawearie Wind Limited | Milnthorpe | 2012 |
| Blaydon Enterprises Ltd | Ashford | 2024 |
| Blaze Charging Limited | Wokingham | 2025 |
| Blema Building Services Limited | London | 2015 |
| Blencathra Hydro Limited | Kendal | 2015 |
| Blenches Mill Farm Solar Park Limited | London | 2012 |
| Blenheim Renewables Limited | London | 2022 |
| Blisworth Hill Renewables Ltd | Towcester | 2023 |
| Blisworth Solar Limited | Reading | 2015 |
| Blizzard Utilities Limited | Hemel Hempstead | 2006 |
| BLJ Electrical Services Limited | Longfield | 1997 |
| Bloomsbury Heat & Power II Limited | London | 2023 |
| Bloomsbury Heat & Power Limited | London | 1998 |
| Blossom 1 Solar Limited | Bristol | 2020 |
| Blossom 2 Solar Limited | Bristol | 2020 |
| Bloxwich Energy Storage Limited | London | 2017 |
| BLP Maintenance Ltd | Chatham | 2020 |
| BLS Energy Limited | Carshalton | 2023 |
| BLU Ocean Living Limited | London | 2020 |
| Blue & Sky Limited | Manchester | 2006 |
| Blue 2 Solutions Limited | Altrincham | 2017 |
| Blue Energy (Poniel) Limited | Alderley Edge | 2019 |
| Blue Energy Brokers Limited | Leeds | 2017 |
| Blue Energy Wind Limited | Alderley Edge | 2010 |
| Blue Flame Investments Ltd | Manchester | 2013 |
| Blue Flames Associates Limited | Sutton | 2010 |
| Blue GAS Services Limited | Birmingham | 2025 |
| Blue House Farm Solar Limited | Reading | 2015 |
| Blue Kite Renewable Energy Solutions Ltd | London | 2024 |
| Blue Moon Farms Ltd | Cheadle | 2013 |
| Blue Nose Refrigeration Ltd | Plymouth | 2010 |
| Blue Oak Group Ltd | London | 2025 |
| Blue Planet Solar Limited | Houghton Le Spring | 2019 |
| Blue Planet Solar Park II Limited | Mexborough | 2014 |
| Blue Reserve Limited | London | 2024 |
| Blue Shark Hydrokinetics Ltd | London | 2025 |
| Blue Sky Contractors Limited | Broadstairs | 2014 |
| Blue Sky Students Limited | Rayleigh | 2015 |
| Blue Stone Renewable I Ltd | Bristol | 2020 |
| Blue Stone Renewable IV Limited | Edinburgh | 2020 |
| Blue Stone Renewable V Limited | Edinburgh | 2020 |
| Blue Stone Renewable VI Limited | Edinburgh | 2020 |
| Blue Sustainable Power Ltd | Edgware | 2025 |
| Blue Transmission London Array (Holdings) Limited | London | 2012 |
| Blue Transmission London Array Limited | London | 2012 |
| Blue Transmission Walney 1 (Holdings) Limited | London | 2010 |
| Blue Transmission Walney 1 Limited | London | 2010 |
| Blue Transmission Walney 2 (Holdings) Limited | London | 2011 |
| Bluebell Energy Supply Limited | Kirkham | 2015 |
| Bluebell Wood Solar Farm Limited | London | 2022 |
| Blueclair Inc Limited | Tamworth | 2014 |
| Bluefield Construction Management Limited | Bristol | 2023 |
| Bluefield Energy Limited | Cardiff | 2015 |
| Bluefield Renewable Developments Limited | Bristol | 2020 |
| Bluefield Renewables 1 Limited | Gatwick | 2022 |
| Bluefield Renewables 2 Limited | Gatwick | 2022 |
| Blueflame (Bristol) Limited | Stratford Upon Avon | 2015 |
| Bluefloat Energy Scotland Holdco 1 Ltd | Edinburgh | 2022 |
| Bluefloat Energy Scotland Holdco 2 Ltd | Edinburgh | 2022 |
| Bluefloat Energy Scotland Holdco 4 Ltd | Edinburgh | 2022 |
| Bluefloat Energy Scotland Holdco 5 Ltd | Edinburgh | 2022 |
| Bluefloat Energy UK Holdings 2 Ltd | Bristol | 2022 |
| Bluefloat Energy UK Holdings Limited | Bristol | 2020 |
| Bluefloat Scotland Renewables Holdco 2, Ltd | Edinburgh | 2021 |
| Bluegates Solar Limited | Hove | 2013 |
| Bluegrid Services Ltd | Llandudno | 2025 |
| Blueprint Trade Powervault Limited | Sandbach | 2026 |
| Bluestone Beddington 1 Ltd | Canvey Island | 2023 |
| Bluestone Beddington 2 Ltd | Canvey Island | 2023 |
| Bluestone Bexley 1 Ltd | Canvey Island | 2023 |
| Bluestone Bexley 2 Ltd | Canvey Island | 2024 |
| Bluestone Biogas Limited | Guildford | 2024 |
| Bluestone Bonnybridge 1 Ltd | Canvey Island | 2024 |
| Bluestone Butt Lane 1 Ltd | Canvey Island | 2023 |
| Bluestone Cathkin 1 Ltd | Canvey Island | 2024 |
| Bluestone Coatbridge Ltd | Canvey Island | 2024 |
| Bluestone Dougliehill 1 Ltd | Canvey Island | 2024 |
| Bluestone Drakelow 1 Ltd | Canvey Island | 2023 |
| Bluestone Dryfield Ltd | Canvey Island | 2025 |
| Bluestone East Lamberkin 1 Ltd | Canvey Island | 2024 |
| Bluestone Emerald 1 Ltd | Canvey Island | 2025 |
| Bluestone Energy Holdings Ltd | Canvey Island | 2024 |
| Bluestone Energy Ltd | Canvey Island | 2018 |
| Bluestone Frodsham 1 Ltd | Canvey Island | 2023 |
| Bluestone Hawkesbury 1 Ltd | Canvey Island | 2022 |
| Bluestone Laceys Farm Ltd | Canvey Island | 2021 |
| Bluestone Laigh Park 1 Ltd | Canvey Island | 2021 |
| Bluestone Lebanon Farm 1 Ltd | Canvey Island | 2021 |
| Bluestone Lebanon Farm 2 Ltd | Canvey Island | 2021 |
| Bluestone Linton-On-Ouse 1 Ltd | Canvey Island | 2024 |
| Bluestone Linwood 1 Ltd | Canvey Island | 2023 |
| Bluestone Llwyn-Onn 1 Ltd | Canvey Island | 2020 |
| Bluestone Malcolmwood 1 Ltd | Canvey Island | 2024 |
| Bluestone Malcolmwood Solar Ltd | Canvey Island | 2025 |
| Bluestone Middleton Farm 1 Ltd | London | 2022 |