26 companies sell for two or more battery sites
Who actually sells the fleet's power, how much they run, and what the book earned across the three measured lines in the 364 days to 27 September 2026. Rates are pounds per kilowatt per year across the whole book; the mix behind each rate is on its page.
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, and the money it earned under an earlier code at the same seller is in that seller's book.
The other half of the question, who owns the batteries these companies sell for, is on the owner pages.
Sites that sell for themselves
One registered seller, one site. A large asset often trades through its own company rather than a platform; the twelve largest are here and each site's own page carries its figures.
| Seller | MW |
|---|---|
| Alcemi Storage Developments 4 | 512 |
| Zenobe Kilmarnock South LTD | 313 |
| Thurrock Storage Limited | 300 |
| Zenobe Blackhillock Limited | 209 |
| SSE Battery Salisbury Limited | 152 |
| Zenobe Capenhurst Limited | 105 |
| Lakeside Energy Storage Ltd | 105 |
| Dollymans Storage Limited | 102 |
| KXP Immingham Ltd | 81 |
| West Burton B Limited | 62 |
| HD143OCK Ltd | 58 |
| HD777FRY Ltd | 57 |
3.8 GW of documented contracts that the register does not name
Every line here is identified: the site, the party, the kind of arrangement and the document it comes from. What is missing is the register's confirmation, for one of three reasons, and the three must not be added together.
Behind a vehicle: 1,361 MW
The battery is registered, the register names a special purpose vehicle as the seller, and the contract announcement names the company that actually optimises it.
| Site | MW | Party and arrangement |
|---|---|---|
| Coalburn 1 RES is asset manager | 512 | SSE Energy Markets, optimisation agreement, ten years, from 2026 confirmed source |
| Thurrock Storage signed 2023; commercial operations 3 November 2025 | 300 | Statkraft, PPA with a revenue floor, plus optimisation, from 2023 confirmed source |
| Lakeside RES asset manager; TagEnergy owns | 105 | Habitat Energy, route to market, from 2024 confirmed source |
| KXP Immingham appointed January 2025 | 81 | Conrad Energy, optimisation agreement, from 2025 confirmed source |
| Wishaw may have been superseded since | 51 | Centrica, route to market, named at the 2022 build, from 2022 probable source |
| Kilmarnock South | 313 | EDF, route to market on Kraken, from 2026 confirmed source |
No registration: 452 MW
Tolls and optimisation agreements on batteries that have no registration of their own, or that trade inside another company's identity. These are the contracts behind the unseen fleet.
| Site | MW | Party and arrangement |
|---|---|---|
| Arlington Energy trio one hour plants, RGREEN backed | 89 | Centrica Business Solutions, ten year contract on FlexPond, from 2022 confirmed source |
| Bramley (Penso Power and BW ESS) no registration anywhere we read | 100 | Shell Energy, seven year fixed price toll, the UK's first single asset BESS toll, from 2024 confirmed source |
| Minety (CHG and CNIC) trades inside Limejump's identity | 100 | Shell Energy Europe (Limejump optimises), multiyear offtake, from 2020 confirmed source |
| Loudwater (Eku) no visible registration | 40 | Statkraft, optimisation, from 2024 confirmed source |
| Basildon (Eku) no visible registration | 28 | Habitat Energy, optimisation, from 2024 confirmed source |
| Low Carbon quartet (Meadow, Sandon Brook, Fern Brook, Birch) no visible registration | 95 | Habitat Energy, Flexitricity and EDF, revenue share, KrakenFlex dispatching, from 2025 confirmed source |
Not yet built: 1,987 MW
Signed for batteries still being built. Forward book, not a gap in the register: each will appear under a seller name when it registers, and this ledger will say whether that name matches the document.
| Site | MW | Party and arrangement |
|---|---|---|
| Eku Ocker Hill (late 2026) | 99 | SmartestEnergy (Marubeni), ten year toll, the longest in the UK at signing, from 2026 confirmed source |
| Penn BESS (early 2028) | 128 | Statkraft, optimisation with a long term income guarantee, from 2028 confirmed source |
| Hams Hall (BW ESS, Q4 2026) Sungrow grid forming | 400 | EDF (PowerShift), ten year revenue floor with profit share, from 2026 confirmed source |
| West Burton C (Fidra, 2028) | 500 | Drax, long term offtake for half the capacity, from 2028 confirmed source |
| Eccles (Matrix Renewables, summer 2027) Tesla holds the full EPC | 500 | EDF (Powershift), route to market and optimisation, from 2027 confirmed source |
| Cero and Enso portfolio (Bramley co-location and two sites approaching operation) £200m green loan, July 2025 | 360 | EDF, route to market, from 2026 confirmed source |
Where the owner sells it and the register agrees: 151 MW
One site, sold by the company that owns it, with the arrangement documented. Not in the figure above, because the register does name the party.
| Site | MW | Party and arrangement |
|---|---|---|
| Dollymans | 102 | Statera Energy, self-trading end to end, from 2023 confirmed source |
| Roosecote (Centrica) | 49 | Centrica, self-operated from its Energy Centre virtual power plant, from 2018 confirmed source |
Wholesale trading income is invisible for everyone on this page, in both directions: nothing here nets charging costs either. Methods