43 groups own 98 per cent of Britain's operating battery capacity
The market registers name the company that sells a battery's power and, for most batteries, a project company with a name that tells a reader nothing. This list follows each project company up to the group behind it, using its control filing at Companies House or the owner's own published statement, and every group's page prints the document behind each join.
| Group | Batteries | MW | Of the fleet | Sold by | Grade |
|---|---|---|---|---|---|
| Gresham House Energy Storage Fund | 30 | 966 | 14.1% | Habitat Energy Limited and 8 others | 26 confirmed, 4 probable |
| Zenobe Energy | 22 | 824 | 12.0% | Itself and 4 others | 21 confirmed, 1 probable |
| Copenhagen Infrastructure Partners (Alcemi develops) | 5 | 512 | 7.5% | Alcemi Storage Developments 4 | 5 confirmed |
| Voltwise Power (Sandbrook Capital) | 10 | 446 | 6.5% | EDF Energy Customers Limited | 10 confirmed |
| Harmony Energy Income Trust (assets under Foresight Group) | 10 | 439 | 6.4% | BP Gas Marketing Limited and 1 other | 5 confirmed, 5 probable |
| Statera Energy | 4 | 402 | 5.9% | Thurrock Storage Limited and 1 other | 4 confirmed |
| TagEnergy | 7 | 324 | 4.7% | Tesla Motors Limited and 2 others | 7 confirmed |
| Pivot Power (EDF Renewables UK) | 6 | 307 | 4.5% | Pivoted Power LLP and 1 other | 6 confirmed |
| Gore Street Energy Storage Fund | 10 | 234 | 3.4% | Gore Street Energy Trading Limited and 2 others | 7 confirmed, 2 probable, 1 named |
| SSE | 3 | 201 | 2.9% | Itself | 3 confirmed |
| FRV (Abdul Latif Jameel) | 4 | 142 | 2.1% | Tesla Motors Limited | 2 confirmed, 2 probable |
| BlackRock and KX Power joint venture | 3 | 138 | 2.0% | KXP Immingham Ltd and 2 others | 3 confirmed |
| Conrad Energy | 7 | 129 | 1.9% | Itself and 1 other | 6 confirmed, 1 probable |
| Sembcorp (UK Power Reserve) | 5 | 117 | 1.7% | UK Power Reserve Limited | 1 confirmed, 4 named |
| Constantine Energy Storage | 2 | 115 | 1.7% | HD143OCK Ltd and 1 other | 2 confirmed |
| Varco Energy (Adaptogen Capital) | 2 | 114 | 1.7% | Arenko Cleantech Limited | 2 confirmed |
| ScottishPower Renewables (Iberdrola) | 2 | 102 | 1.5% | SP Renewables (UK) Limited | 2 confirmed |
| ENGIE | 3 | 102 | 1.5% | Itself | 2 confirmed, 1 named |
| Pulse Clean Energy | 5 | 100 | 1.5% | Habitat Energy Limited | 4 confirmed, 1 probable |
| Sosteneo (Pacific Green developed) | 2 | 100 | 1.5% | Limejump Energy Limited | 2 confirmed |
| Field (Virmati Energy Ltd) | 4 | 86 | 1.3% | Itself | 4 confirmed |
| SUSI Partners and Eelpower joint venture | 4 | 83 | 1.2% | Habitat Energy Limited and 2 others | 2 confirmed, 2 probable |
| UK Transition Power | 2 | 62 | 0.9% | West Burton B Limited | 2 confirmed |
| Cero Generation and Enso Energy joint venture | 1 | 57 | 0.8% | EDF Energy Customers Limited | 1 confirmed |
| Eku Energy | 3 | 54 | 0.8% | EDF Energy Customers Limited and 1 other | 3 confirmed |
| Cero Generation (Macquarie Green Investment Group) | 1 | 52 | 0.8% | EDF Energy Customers Limited | 1 confirmed |
| Statkraft | 1 | 50 | 0.7% | Itself | 1 confirmed |
| Amber Energy | 1 | 50 | 0.7% | Tesla Motors Limited | 1 confirmed |
| Amp Clean Energy | 1 | 49 | 0.7% | Tollgate Energy Storage Ltd | 1 confirmed |
| Centrica | 2 | 49 | 0.7% | CBS Energy Storage Assets LTD | 2 confirmed |
| Econergy | 1 | 49 | 0.7% | BGI Trading Limited | 1 confirmed |
| Downing | 1 | 48 | 0.7% | EDF Energy Customers Limited | 1 confirmed |
| Equinor (Noriker Power develops and operates) | 2 | 43 | 0.6% | Danske Commodities A/S and 1 other | 2 confirmed |
| Verdant (Enso Energy developed) | 1 | 40 | 0.6% | Arenko Cleantech Limited | 1 confirmed |
| RGREEN INVEST (Arlington Energy developed) | 2 | 35 | 0.5% | Centrica Business Solutions UK Optimisation Limited and 1 other | 2 confirmed |
| Atlantic Green | 2 | 30 | 0.4% | BGI Trading Limited | 2 confirmed |
| Vattenfall | 1 | 22 | 0.3% | Arenko Cleantech Limited | 1 confirmed |
| Opium Power and Somerset Council joint venture | 1 | 18 | 0.3% | Limejump Energy Limited | 1 confirmed |
| Voltalia | 1 | 18 | 0.3% | Habitat Energy Limited | 1 confirmed |
| GridBeyond | 8 | 13 | 0.2% | Itself | 8 confirmed |
| Doncaster Power Projects | 1 | 10 | 0.1% | Vest Energy Limited | 1 confirmed |
| Gridserve | 2 | 9 | 0.1% | EDF Energy Customers Limited | 2 confirmed |
| Ecotricity | 1 | 5 | 0.1% | Itself | 1 confirmed |
Largest first; click a heading to sort by it. A battery that re-registered under a new code is counted once, under the code it runs on today. Sold by names the largest seller by megawatt; the group's page lists them all. Grades: confirmed means a control filing or the owner's own statement names the company; probable means strong indirect evidence, such as a capacity market site of the same size a few hundred metres away; named means a sibling unit at the same site is settled and the code carries the owner's initials.
19 batteries, 104 MW, where no document names the owner yet
The honest state of the rest. Some are project companies waiting on a single filing. Some name nobody at all in either register, and the site itself has to be identified before the company can be. A prefix on a unit code is not evidence: eleven units carry a code that looks like one operator's and the only one the register names belongs to somebody else.
| Battery | MW | What the register names | Sold by |
|---|---|---|---|
| South Gloucestershire Cotswold | 44 | no owner in either register | BGI Trading Limited |
| Sheffield (EONDC-03) North Midlands and North Wales | 10 | no owner in either register | E.On UK Heat Limited |
| West Lindsey North Midlands and North Wales | 10 | no owner in either register | Habitat Energy Limited |
| UF_FLX02 Essex and Kent | 9 | no owner in either register | Flexitricity Limited |
| Newark and Sherwood (RUFF-1) North Midlands and North Wales | 6 | no owner in either register | Equinicity LTD |
| Edfe-1 Mid Wales and The Midlands | 5 | no owner in either register | EDF Energy Customers Limited |
| Eondc-01 Somerset and Wessex | 4 | no owner in either register | E.On UK Heat Limited |
| Huntingdonshire South Lincolnshire and North Norfolk | 3 | no owner in either register | Peak GEN TOP CO Limited |
| South Hams West Devon and Cornwall | 2 | no owner in either register | Vest Energy Limited |
| UF_KFLX01 Central London | 2 | no owner in either register | Octopus Energy Limited |
| County Durham (ANSC-008) North East England | 1 | no owner in either register | Anesco Limited |
| County Durham (ANSC-003) North East England | 1 | no owner in either register | Anesco Limited |
| County Durham (ANSC-009) North East England | 1 | no owner in either register | Anesco Limited |
| Ansc-005 South Lancashire, Yorkshire and Humber | 1 | no owner in either register | Anesco Limited |
| Ansc-006 South Lancashire, Yorkshire and Humber | 1 | no owner in either register | Anesco Limited |
| Stratford-on-Avon Mid Wales and The Midlands | 1 | no owner in either register | Anesco Limited |
| Basingstoke and Deane Oxfordshire, Surrey and Sussex | 1 | no owner in either register | Anesco Limited |
| Ansc-010 Mid Wales and The Midlands | 1 | no owner in either register | Anesco Limited |
| North Norfolk Mid Wales and The Midlands | 1 | no owner in either register | Krakenflex Limited |
How the owner is decided
A control filing decides it. Companies House publishes, for every company, who holds more than a quarter of it and who can appoint and remove its directors. We follow that chain up from the project company until it stops and record where it stopped. Everything else is a lead to be checked against one: a capacity market site a few hundred metres from an ownerless unit, a second phase at the same postcode, a company's previous names, the initials in a balancing code. Shared directors and shared registered offices are not evidence, because both survive a sale. The finding says why the registers cannot answer this question, and the optimiser pages are the other half of it: who sells.