Hallen
18 MW, about 18 MWh (1 hour, from the capacity market de-rating class) in Cotswold. Everything on this page is read from published data for the 364 days to 27 September 2026, or is labelled as an estimate.
What it is
| Registered power | 18 MW response and reserve auction registration |
| Storage duration | 1 hour capacity market de-rating class |
| Charging zone | Cotswold |
| Connection site | South Gloucestershire |
| Postcode | BS10 7SE |
| Balancing mechanism unit | none found under the codes we search |
Who owns it and who trades it
| Traded by | HABITAT ENERGY LIMITEDruns several sitesauction results, unchecked |
| Owned by | Hallen Energy Ltd |
| Owner established from | capacity market registered holder |
| Ultimately | Voltalia confirmed source |
How we know. Voltalia's first UK battery, per Voltalia and the Wilson Power build record.
Market registers name the party that sells into the market, which for a battery is usually an optimiser under contract rather than the owner. This unit is registered only in the response and reserve auctions, so the seller is the participant NESO's auction results name, and Elexon's register carries no entry to check it against. How we tell them apart
What it is built from
| Battery system | BYD: 16 lithium ion modules of 2 MWh each |
| Entered operation | 2021-12 (construction from April 2021) |
| Transformers | Wilson Power: eight 33kV/400V distribution transformers (four 3.2 MVA, four 4.8 MVA T2 Ecotrans) plus a 1.5 MVA auxiliary |
| Connection voltage | 33 kV documented: 33kV/400V transformer fleet on the Wilson project page |
From published documents, not from any register: supplier and contractor project pages, owner announcements and the trade press. Confidence: confirmed. Checked 2026-08-31. source 1 · source 2. Fields not shown are not published anywhere we have found, and we do not guess them.
What it earned
| Line | 364 days to 27 September 2026 |
|---|---|
| Balancing mechanism | not published |
| Response and reserve auctions auction implied | £49k |
| Capacity market | £95k |
| Three lines together | £145k |
Balancing is offer revenue and does not net off the cost of the power. The response and reserve figure is the value implied by the published auction results, award quantity times clearing price times the length of the delivery window, and not a settled payment. Capacity market income is the cleared price raised for inflation where the auction set a base period, split by month on EMRS's weights. Method
Outside the balancing mechanism, estimated from metered peers
Elexon publishes no metered output for this registration, an auction unit rather than a balancing mechanism unit, so nothing can be derived for it. What can be said is what its peers did: 15 units of about 1 hour in England and Wales, metered, earned between £3.49 and £26.07 per kilowatt a year with the balancing legs and the position outside the balancing mechanism together, £5.55 at the median. Applied to this unit's 18 MW that is £100k, in a range of £63k to £469k. An estimate from other batteries, never this one's figure. Method
Where it stands
| All three measured lineswhole fleet, £/kW/yr | 18th percentile229 units |
Percentiles, so 90 means better than nine in ten of the cohort named beside it, on that measure alone, over the same 364 days. Rates are pounds per kilowatt per year, annualised over the days the unit has been on the system, the same figures the performance league ranks on. A high position in the taken-in table is not a fault: a constraint asset is paid to charge, and charging is its job.
The nearest comparables
The five nearest in size in England and Wales, and this battery among them, ranked by what each was paid for every kilowatt it holds over the 364 days to the same date. They run for about the same length of time. Same market, same rules, same weather.
| Battery | MW | Hours | Measured, per kW |
|---|---|---|---|
| Flatworth | 17 | 1h | £57.0/kW/yr |
| Gses 1 (GSET-04) | 18 | 1h | £43.8/kW/yr |
| Gses 1 (GSET-05) | 18 | 1h | £40.9/kW/yr |
| Fareham Reserve | 18 | 1h | £34.5/kW/yr |
| Gses 1 (GSET-03) | 18 | 1h | £33.0/kW/yr |
| Hallenthis battery | 18 | 1h | £8.1/kW/yr |
See it on the map
Every figure on this page traces to a published file. If something here is wrong about your asset, the methods section says how to tell us.