Auchteraw
49 MW, about 98 MWh (2 hours, from the capacity market de-rating class) in Western Highlands. Everything on this page is read from published data for the 364 days to 16 October 2026, or is labelled as an estimate.
What it is
| Registered power | 49 MW response and reserve auction registration |
| Storage duration | 2 hours capacity market de-rating class |
| Charging zone | Western Highlands |
| Connection site | Highland |
| Postcode | PH32 4BT |
| Balancing mechanism unit | 2__PFLEX002 a supplier unit registered by the company that trades it; its balancing actions are counted on this page |
Who owns it and who trades it
| Traded by | Flexitricity Limitedruns several sitesconfirmed, Elexon's register |
| Owned by | FIELD AUCHTERAW LTD. |
| Owner established from | capacity market registered holder |
| Ultimately | Field (Virmati Energy Ltd) confirmed source |
How we know. The SPVs carry Field's name; Field is the trading name of Virmati Energy Ltd, and DIF Capital Partners' £200m investment of July 2023 funds the fleet.
Market registers name the party that sells into the market, which for a battery is usually an optimiser under contract rather than the owner. Elexon's balancing mechanism unit register names the seller here and the name is checked against it on every build. How we tell them apart
What it is built from
| Engineering and construction | Powersystems UK, principal contractor for civil and electrical balance of plant; RJ McLeod, substation civils and cable route |
| Container count | 316 battery cubes, 14 BESS transformers |
From published documents, not from any register: supplier and contractor project pages, owner announcements and the trade press. Confidence: confirmed (cell maker not named in these sources). Checked 2026-10-06. 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 16 October 2026 |
|---|---|
| Balancing mechanism | −£3.2m |
| Response and reserve auctions auction implied | £1.4m |
| Capacity market | £273k |
| Three lines together | not netted |
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, derived from the meter
Elexon publishes what this unit's meter recorded every half hour. Take away the balancing volumes NESO accepted and what is left is the position the unit ran outside the balancing mechanism: its wholesale trading, its frequency response delivery, and its losses, together. This unit held a frequency response contract in 6,108 of those half hours. The energy the contract asked of it, contracted megawatts times NESO's published delivery curve at the measured grid frequency, is taken out of the position and valued at the imbalance price, because it sits outside the unit's declared position and that is the price Elexon settles it at. What remains is the traded position, valued at the market index. In 4 half hours a contract was held but the grid frequency is not yet held, so those are left in the traded position. The volumes are measured. The prices are public benchmarks, not this unit's trades. The product is derived, and is shown apart from the three measured lines above. 359 days to 11 October 2026, 45 of them still provisional in Elexon's settlement runs. Method and caveats
| Line | MWh or £ |
|---|---|
| Metered export, what crossed the meter out | 37,116 MWh |
| Metered import, what crossed the meter in | 35,672 MWh |
| Equivalent full cycles, everything sent out over one full charge | 379 over 359 days, 385 a year at that rate |
| Apparent meter to meter efficiency | 104%, exceptionally efficient, or a short measurement period |
| Balancing offers accepted | 1,386 MWh |
| Balancing bids accepted | 52,750 MWh |
| Position outside balancing, export | 73,249 MWh |
| Position outside balancing, import | 20,441 MWh |
| Of which expected response delivery, net | 13 MWh 2,805 out, 2,792 in |
| Traded position, net | 52,796 MWh 72,355 out, 19,559 in |
| Traded position at the market index, sold | £8.0m |
| Traded position at the market index, bought | £1.5m |
| Traded position, net, at the index | £6.4m |
| Response delivery, net, at the imbalance price | −£93k −£76k at the index |
| Balancing and outside balancing together | £3.3m £67.65/kW/yr |
When it moved, against when power was dear
Across every half hour this unit was metered the market index averaged £97.34. What it sent out was worth £110.20 a megawatt hour at that same index, 1.13 times the average. What it took in was worth £77.99, 0.80 times. Selling above one and buying below one is a unit positioned into the dear half hours and out of the cheap ones. It measures the half hours it chose, not the price anyone paid it, which is not published.
What it paid to buy energy back
When NESO accepts a bid, this unit delivers less than it had already sold, or takes more in. It pays for the energy it no longer delivers, and that payment is most of what makes the balancing figure above negative. Whether that is a cost or a margin depends on the price it paid. Across 52,750 MWh of accepted bids it paid an average of £62.09 a megawatt hour. The market index averaged £107.16 across those same half hours, so it bought back at £45.07 a megawatt hour below the going price.
| Price it paid | Volume | Average | Cash |
|---|---|---|---|
| below zero | 3,068 MWh | −£18.02 | £55k received |
| £0 to £25 | 4,348 MWh | £13.46 | £59k |
| £25 to £50 | 9,979 MWh | £39.14 | £391k |
| £50 to £75 | 17,792 MWh | £62.22 | £1.1m |
| £75 to £100 | 9,578 MWh | £86.01 | £824k |
| above £100 | 7,984 MWh | £119.04 | £950k |
On 3,068 MWh the price was below zero: NESO paid this unit an average of £18.02 a megawatt hour to take energy, £55k in all. That is a constrained network with more generation on it than it can move.
The other direction, offers, is much smaller here: 1,386 MWh where NESO asked for more, paid at an average of £129.95 against an index of £112.53.
Checks this unit did not pass cleanly. Published anyway, because a flagged figure with its flag is more use than a blank.
- exports exceed imports (1.04), so something behind this meter generates: a co-located site, not a battery alone
- the meter exceeded the 49.0 MW registration on 30 days between 2025-10-18 and 2026-03-18, peaking at 96 MW export and 51 MW import: more than this battery can do, so another asset on the same meter, a commissioning period, or a settlement run error
Where it stands
| All three measured lineswhole fleet, £/kW/yr | 51st percentile230 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 Scotland, 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 |
|---|---|---|---|
| Camilla | 49 | 1.5h | £98.1/kW/yr |
| Wishaw BESS | 51 | 2h | £43.0/kW/yr |
| East Ayrshire (KILSB-2) | 52 | 2h | £2.0/kW/yr |
| East Ayrshire (KILSB-1) | 53 | 2.1h | £0.5/kW/yr |
| Neilston Battery 1 | 50 | 1.9h | £0.0/kW/yr |
| Auchterawthis battery | 49 | 2h | not netted |
The three lines are not added together for this site. It paid £3.4m to charge and the lines we can measure paid it £1.8m. The energy it bought was sold in the wholesale market and nothing published measures that sale, so subtracting one from the other would show a loss it does not make. Sites in this position are usually constraint assets, paid to absorb wind the network cannot move south.
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.