TagEnergy
Owns 7 batteries at 6 sites, 324 MW, which is 4.7 per cent of everything operating in Great Britain. It sells none of that power itself. The register names 3 other companies as the sellers: Tesla Motors Limited, Lakeside Energy Storage Ltd and Pivoted Power LLP.
Who sells its power
The balancing mechanism register names the company allowed to sell each unit's power. That company is usually an optimiser or a supplier working under contract, which is why the registers cannot answer the ownership question on their own. Where the seller is one of the owner's own companies, the row says so.
| Seller | Batteries | MW | Of this fleet |
|---|---|---|---|
| Tesla Motors Limited | 5 | 169 | 52% |
| Lakeside Energy Storage Ltd | 1 | 105 | 32% |
| Pivoted Power LLP | 1 | 50 | 15% |
What it was paid
The three published lines, added up across the fleet for the 364 days to 6 September 2026. Wholesale trading income is invisible for every owner, not just this one, and nothing here nets the cost of charging. The rate is per kilowatt of current capacity.
| Balancing mechanism, paid to discharge | £17.8m |
| Balancing mechanism, paid out to charge | −£13.0m |
| Response and reserve auctions | £2.0m |
| Capacity market | £2.4m |
| Income across the fleet, per kilowatt | £68.52/kW/yr fleet 35.48 |
| Median battery, all three lines | £69.56/kW/yr |
| Hours at full power, sent out | 510 h/yr |
| Hours at full power, taken in | 599 h/yr |
What the fleet is made of
Duration, by megawatt
Region, by megawatt
Every battery it owns
| Battery | MW | Sold by | Grade | £/kW/yr |
|---|---|---|---|---|
| Lakeside BESS South Lancashire, Yorkshire and Humber | 105 | Lakeside Energy Storage Ltd | confirmed | 69.56 |
| Sundon BESS Mid Wales and The Midlands | 50 | Pivoted Power LLP | confirmed | 105.38 |
| Chapel Farm BESS Mid Wales and The Midlands | 50 | Tesla Motors Limited | confirmed | 88.12 |
| Roaring Hill BESS Stirlingshire and Fife | 50 | Tesla Motors Limited | confirmed | 39.70 |
| Jamesfield 1 Battery Storage Eastern Grampian and Tayside | 30 | Tesla Motors Limited | confirmed | 36.52 |
| Hawkers Hill Battery Somerset and Wessex | 20 | Tesla Motors Limited | confirmed | 81.81 |
| Jamesfield 2 Battery Storage Eastern Grampian and Tayside | 19 | Tesla Motors Limited | confirmed | 25.90 |
How we know
Confirmed means a control filing at Companies House, or the owner's own published statement, names the company. Probable means the evidence is strong and indirect. Named means the register leaves the owner blank, the balancing code carries the owner's initials, and a sibling unit at the same site is already settled. Each chain below is printed once, with the batteries it settles.
Confirmed Sundon BESS, Chapel Farm BESS, Jamesfield 1 Battery Storage
The control filing on each names Tagenergy Uk Limited holding more than half the shares with the right to appoint and remove directors, since 22 October 2021. Harmony Energy holds the rest and developed the sites. Source
Confirmed Lakeside BESS
TagEnergy's own energisation announcement. Source
Confirmed Roaring Hill BESS
The control filing shows RES UK & Ireland Limited handing the company to TagEnergy UK Limited on 30 September 2021, at three quarters or more with the right to appoint directors. The capacity market still names RES as the holder and the registered office is still RES's, so both would have given the wrong answer. Source
Confirmed Hawkers Hill Battery
The control filing gives the company to TagEnergy UK Limited at three quarters or more with the right to appoint directors, since November 2020, and an individual held it before that. The capacity market agrees, holding a site called Hawkers Hill in the TagEnergy name 230 metres away. The registered office is RES's, which reflects who developed and administers it rather than who owns it. Source
Confirmed Jamesfield 2 Battery Storage
The register names no owner for phase two. Phase one sits at the same postcode and the same coordinates and is held by Harmony JF Limited, which TagEnergy controls. Source
Attribution. A battery belongs to whoever the documents name today, so a fleet that changed hands during the year credits the whole year to the current owner. Groups are joined only where a filing joins them; a company that holds through several vehicles appears once, under the name at the top of the chain. Directors and registered offices are never used as evidence on their own. Why the registers cannot answer this question