Vitreous LabsEnergy transparency

East Ayrshire (KILSB-1)

53 MW, about 111 MWh (2.1 hours, measured from its behaviour) in South West Scotland. Everything on this page is read from published data for the 364 days to 27 September 2026, or is labelled as an estimate.

Part of East Ayrshire, one of 6 balancing units at one site totalling 313 MW. This page is the T_KILSB-1 unit alone.

What it is

Registered power53 MW balancing mechanism registration
Storage duration2.1 hours measured from twenty one days of behaviour
Charging zoneSouth West Scotland
Connection siteEast Ayrshire
PostcodeKA1 3TN
Balancing mechanism unitT_KILSB-1

Who owns it and who trades it

Traded byZENOBE KILMARNOCK SOUTH LTDconfirmed, Elexon's register
Owned bynot published anywhere we can read
UltimatelyZenobe Energy confirmed source

How we know. The register names no owner for these six units. The lead party is Zenobe Kilmarnock South Limited, whose filings give Zenobe Blackhillock Borrower Limited as its controller since January 2024 and Zenobe Energy Limited before that.

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 earned

Line364 days to 27 September 2026
Balancing mechanism−£3k
Response and reserve auctions auction implied£164k
Capacity marketno agreement we can attach
Three lines together£161k

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 8,243 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 9 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. 328 days to 12 September 2026, 33 of them still provisional in Elexon's settlement runs. Method and caveats

LineMWh or £
Metered export, what crossed the meter out27,114 MWh
Metered import, what crossed the meter in30,786 MWh
Equivalent full cycles, everything sent out over one full charge244 over 328 days, 271 a year at that rate
Apparent meter to meter efficiency88%, an ordinary battery: round trip losses alone
Balancing offers accepted5,733 MWh
Balancing bids accepted13,087 MWh
Position outside balancing, export31,318 MWh
Position outside balancing, import27,636 MWh
Of which expected response delivery, net−8,643 MWh 3,595 out, 12,238 in
Traded position, net12,325 MWh 33,463 out, 21,138 in
Traded position at the market index, sold£3.7m
Traded position at the market index, bought£1.7m
Traded position, net, at the index£2.0m
Response delivery, net, at the imbalance price−£960k −£905k at the index
Balancing and outside balancing together£1.1m £22.63/kW/yr

When it moved, against when power was dear

Across every half hour this unit was metered the market index averaged £94.10. What it sent out was worth £109.85 a megawatt hour at that same index, 1.17 times the average. What it took in was worth £78.87, 0.84 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 13,087 MWh of accepted bids it paid an average of £51.68 a megawatt hour. The market index averaged £93.99 across those same half hours, so it bought back at £42.31 a megawatt hour below the going price.

Price it paidVolumeAverageCash
below zero1,736 MWh−£20.50£36k received
£0 to £251,297 MWh£11.92£15k
£25 to £501,882 MWh£39.55£74k
£50 to £754,630 MWh£64.48£299k
£75 to £1002,733 MWh£83.53£228k
above £100809 MWh£117.71£95k

On 1,736 MWh the price was below zero: NESO paid this unit an average of £20.50 a megawatt hour to take energy, £36k in all. That is a constrained network with more generation on it than it can move.

The other direction, offers, is much smaller here: 5,733 MWh where NESO asked for more, paid at an average of £123.07 against an index of £100.18.

Physical checks passed: the meter never exceeded the registered power by more than fifteen per cent, and the year's exports against imports are what a battery does.

Where it stands

Balancing incomewhole fleet, £/kW/yr53rd percentile98 units
Balancing incomeScotland peer group89th percentile28 units
Balancing income2.1 hour duration cohort38th percentile62 units
All three measured lineswhole fleet, £/kW/yr31st percentile229 units
Energy sent outhours at full power47th percentile96 units
Energy taken inhours at full power53rd percentile96 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.

BatteryMWHoursMeasured, per kW
Wishaw BESS512h£44.7/kW/yr
Auchteraw492h£33.3/kW/yr
Erskine BESS302h£11.1/kW/yr
East Ayrshire (KILSB-2)522h£3.1/kW/yr
East Ayrshire (KILSB-1)this battery532.1h£3.0/kW/yr
Shilton Lane BESS402h£2.2/kW/yr

See it on the map

Open the operating map here

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.