The four companies that sell the most battery power in Britain own none of it
Every battery on the system has a company registered to sell its power, and the registers name it. That company is usually not the owner. Counted by megawatt across the 6,849 MW of operating capacity that carries a named seller, 4,635 MW is sold by a company that owns none of the battery, 68 per cent of the fleet. The owner's own house sells the other 2,214 MW, 32 per cent. The four largest sellers, EDF Energy Customers Limited, Habitat Energy Limited, Tesla Motors Limited and Alcemi Storage Developments 4, hold 2,472 MW between them and own none of it.
Who sells the fleet, and for whom
The registers name 55 different selling companies across the operating fleet, and 30 of them sell for two or more batteries. Those are the ones with a book worth looking at, and they are here largest first.
| Seller | Batteries | MW | Its own | Somebody else's |
|---|---|---|---|---|
| EDF Energy Customers Limited | 26 | 858 | — | 858 |
| Habitat Energy Limited | 21 | 561 | — | 561 |
| Tesla Motors Limited | 15 | 541 | — | 541 |
| Alcemi Storage Developments 4 | 5 | 512 | — | 512 |
| Zenobe Kilmarnock South LTD | 6 | 313 | 313 | — |
| Pivoted Power LLP | 6 | 311 | 261 | 50 |
| Thurrock Storage Limited | 3 | 300 | 300 | — |
| Octopus Energy Trading Limited | 8 | 298 | — | 298 |
| Arenko Cleantech Limited | 8 | 288 | — | 288 |
| BP Gas Marketing Limited | 5 | 259 | — | 259 |
| Zenobe Blackhillock Limited | 4 | 209 | 209 | — |
| BGI Trading Limited | 5 | 168 | — | 168 |
| SSE Battery Salisbury Limited | 2 | 152 | 152 | — |
| Gore Street Energy Trading Limited | 8 | 145 | 145 | — |
| and 16 more sellers of two or more batteries, each with its own page | ||||
Two shapes sit in this table. Most of the large sellers are optimisers, trading batteries across many sites for owners who hired them. A few are a single site's own company selling its own units, which is why their book is entirely their own and why they have no optimiser page. Current registrations only, so a battery that re-registered under a new code is counted once. “Its own” means the seller is a company of the owner's own group, decided by the list in the owner pages, which names each group's selling companies with the filing behind them. Where we cannot yet name the owner, the megawatts sit in the other column, so that column is the larger of the two claims and the safer one.
Habitat Energy, and the case that shows what this means
Habitat Energy sells 561 MW across 21 batteries and owns not one of them. It is the second largest seller in the fleet. Its book is concentrated: Gresham House Energy Storage Fund, 64 per cent of the book.
Habitat is owned by Quinbrook Infrastructure Partners, which said so itself on 30 November 2021, the same day the control filing for Habitat Energy Limited records its shares passing to a new holding company at 75 per cent or more. Quinbrook is not a passive owner of a trading desk. Its own portfolio names Cleve Hill and Uskmouth as its projects, and both sit in NESO's storage connection register, so the parent of the fleet's second largest seller is also a developer waiting in the same queue as the batteries its subsidiary trades for.
None of that is a fault, and nothing here says it is. An optimiser trading assets it does not own is the ordinary shape of this market, and a developer owning a trading desk is a normal piece of vertical integration. What is not ordinary is that none of it is visible from the registers, which name a seller and stop. A fund choosing an optimiser, a lender pricing a route to market and a developer picking a counterparty all have an interest in knowing whose house the desk belongs to, and until this page there was nowhere to read it.
Where this can be wrong
The seller is whoever the registers name today, so a book that changed hands during the year reads entirely to the current seller. The owner behind a battery comes from control filings and capacity market holders and is not complete: where it is unknown the megawatts count as somebody else's, which pushes the headline share up rather than down, and the unknown is small.
Whether a seller is the owner's own house is a judgement made from filings, group by group, and one that changed on 10 September 2026: Gore Street Energy Trading, Pivoted Power, UK Power Reserve and two more were reading as third parties because their names differ from their owners'. They are listed now, with a document each. A seller not on that list and not named after its owner is called a third party, which is the direction we would rather be wrong in, and ScottishPower Renewables is the open case.
One row in the table deserves its own caveat. Alcemi develops and operates the batteries it sells for, and their owner is Copenhagen Infrastructure Partners. It reads here as a third party because it is a different house from the owner, which is true, and it is not the same thing as an optimiser hired off the street.
The other half of this question, who owns the fleet, counts the same batteries from the ownership side. Every seller has its own page with its book, its shape and what it earned.