| Harthill Wind Limited | Warrington | 2011 |
| Hartlepool Solar Electric Forecourt Ltd | Norwich | 2021 |
| Hartlepool West Solar Farm Ltd | Norwich | 2020 |
| Hartlepool Wind Limited | Hartlepool | 2014 |
| Hartley Services Limited | Hook | 2005 |
| Hartmoor Generation Limited | Kirkby Lonsdale | 2017 |
| Hartmoor Holdings Limited | Kirkby Lonsdale | 2016 |
| Hartree Partners Supply (UK) Limited | London | 2014 |
| Hartsgarth Wind Farm Limited | London | 2023 |
| Hartville GAS Services Ltd | Havant | 2020 |
| Hartwood Windfarm Limited | Edinburgh | 2006 |
| Harvest Generation Services Limited | London | 2014 |
| Harvestlight Solar Ltd | Faversham | 2025 |
| Harworth Dawley Road Limited | Rotherham | 2021 |
| Harworth Power (Generation) Limited | Warrington | 2012 |
| Hasland Green Limited | Preston | 2013 |
| Hastings Power Ltd | Burton-On-Trent | 2011 |
| HAT Energy Limited | London | 2022 |
| Hatch Park Solar Limited | Arundel | 2024 |
| Hatch Ride Properties Ltd | Watlington | 2014 |
| Hatherton Solar Limited | London | 2024 |
| Hatston Wind Power Ltd | Glasgow | 2010 |
| Hatton Solar Farm Limited | Colchester | 2021 |
| Haughmond Hill Solar Farm Limited | London | 2025 |
| Haul Y Gwrhyd CIC | Ammanford | 2025 |
| Haunton Farmers' Solar Limited | London | 2020 |
| Haush Group Ltd | London | 2026 |
| Haush Immingham Ltd | London | 2025 |
| Haush Pembroke Ltd | London | 2024 |
| Haush POP UP Hydrogen Ltd | London | 2025 |
| Havant Biogas Limited | London | 2018 |
| Havbredey Limited | Edinburgh | 2021 |
| Have Some Sun Ltd | London | 2023 |
| Haverigg III Limited | Bristol | 2003 |
| Haverton Hill Power Limited | London | 2018 |
| Hawaii Energy Limited | Kingston Upon Thames | 2019 |
| Hawk Marine Engineering Limited | Beccles | 1986 |
| Hawking Energy Ltd | Ruislip, | 2025 |
| Hawkins Hydro Limited | Newbury | 2011 |
| Hawlmark Energy Limited | Dungannon | 2023 |
| Hawthorn Lighting Ltd | Manchester | 2019 |
| Hawthorn PIT Bess Limited | Cheltenham | 2022 |
| Haxted Mead Solar Farm Limited | Bristol | 2023 |
| HAY Energy Ltd. | Redruth | 2012 |
| HAY Renewables Limited | Edinburgh | 2008 |
| Hayes Electrical Solutions Ltd | Brentwood | 2017 |
| Hayes Holdings Group Ltd | Portsmouth | 2026 |
| Hayhoe Offshore Limited | Durham | 2021 |
| Haymaker (Eighteen) Limited | Eastbourne | 2015 |
| Haymaker (Fourteen) Limited | Eastbourne | 2015 |
| Haymaker (Handley Park Solar) Limited | London | 2014 |
| Haymaker (Honington Solar) Limited | Eastbourne | 2014 |
| Haymaker (Kinmel) Ltd | Eastbourne | 2014 |
| Haymaker (Mount Mill) Ltd | London | 2013 |
| Haymaker (Natewood) Holdings Limited | London | 2014 |
| Haymaker (Natewood) Ltd | London | 2013 |
| Haymaker (Nineteen) Limited | Eastbourne | 2015 |
| Haymaker (Oaklands) Holdings Limited | London | 2014 |
| Haymaker (Oaklands) Ltd | London | 2013 |
| Haymaker (Seventeen) Limited | Eastbourne | 2015 |
| Haymaker (Solar) Limited | London | 2013 |
| Haymaker (Twenty Eight) Limited | Eastbourne | 2022 |
| Haymaker (Twenty Five) Limited | Eastbourne | 2022 |
| Haymaker (Twenty Four) Limited | Eastbourne | 2022 |
| Haymaker (Twenty One) Limited | Eastbourne | 2015 |
| Haymaker (Twenty Seven) Limited | Eastbourne | 2022 |
| Haymaker (Twenty SIX) Limited | Eastbourne | 2022 |
| Haymaker (Twenty Three) Limited | Eastbourne | 2015 |
| Haymaker (Twenty Two) Limited | Eastbourne | 2015 |
| Haymaker (Twenty) Limited | Eastbourne | 2015 |
| Haymaker Energy Limited | Eastbourne | 2013 |
| Haymill Services UK Limited | Feltham | 2018 |
| Hazel Renewables Limited | Kings Langley | 2012 |
| Hazel Solar Ltd | Bath | 2022 |
| Hazelmead Community Energy Limited | Bristol | 2019 |
| Hazlehead Wind Farm Limited | London | 2006 |
| HB Air Conditioning Ltd | Bromsgrove | 2024 |
| HB Electrical Contractors Ltd | London | 2020 |
| HB International Investments Ltd | Manchester | 2019 |
| HB Power Solutions Ltd | Derby | 2025 |
| HB222BRI Ltd | Godalming | 2019 |
| HB333MIL Ltd | Godalming | 2019 |
| HB411MIN Ltd | Godalming | 2019 |
| HB825AXM Ltd | Godalming | 2019 |
| HBY Renewable Energy Ltd | Dundee | 2016 |
| Hbyd Limited | Lanark | 2020 |
| HC ESS2 Limited | London | 2017 |
| HC ESS3 Limited | London | 2017 |
| HC ESS4 Limited | London | 2017 |
| HC ESS6 Limited | London | 2018 |
| HC ESS7 Limited | London | 2018 |
| HD Technical Ltd | Basingstoke | 2024 |
| HD000ACT Ltd | Godalming | 2019 |
| HD143OCK Ltd | Godalming | 2019 |
| HD144WHI Ltd | Godalming | 2019 |
| HD192RAY Ltd | Godalming | 2019 |
| HD381GRE Ltd | Godalming | 2019 |
| HD639LEG Limited | Godalming | 2019 |
| HD777FRY Ltd | Godalming | 2019 |
| HD888CAP Limited | Godalming | 2019 |