Vitreous LabsEnergy transparency

Melksham East

49 MW, about 98 MWh (2 hours, 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 power49 MW response and reserve auction registration
Storage duration2 hours capacity market de-rating class
Charging zoneCotswold
Connection siteWiltshire
PostcodeSN12 7QG
Balancing mechanism unitnone found under the codes we search

Who owns it and who trades it

Traded byHABITAT ENERGY LIMITEDruns several sitesconfirmed, Elexon's register
Owned byMELKSHAM EAST STORAGE LIMITED
Owner established fromcapacity market registered holder
UltimatelyGresham House Energy Storage Fund confirmed source

How we know. Statera's Melksham East page names Gresham House Energy Storage Fund plc as project owner, with Statera as developer, EPC and O&M.

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 mechanismnot published
Response and reserve auctions auction implied£4.6m
Capacity market£631k
Three lines together£5.2m

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 10,298 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 14 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. 346 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 out34,997 MWh
Metered import, what crossed the meter in41,696 MWh
Equivalent full cycles, everything sent out over one full charge357 over 346 days, 377 a year at that rate
Apparent meter to meter efficiency84%, an ordinary battery: round trip losses alone
Balancing offers accepted0 MWh
Balancing bids accepted0 MWh
Position outside balancing, export34,997 MWh
Position outside balancing, import41,696 MWh
Of which expected response delivery, net40,985 MWh 40,985 out, 0 in
Traded position, net−47,685 MWh 10,267 out, 57,952 in
Traded position at the market index, sold£927k
Traded position at the market index, bought£5.5m
Traded position, net, at the index−£4.6m
Response delivery, net, at the imbalance price£4.1m £4.1m at the index
Balancing and outside balancing together−£542k £-11.67/kW/yr

When it moved, against when power was dear

Across every half hour this unit was metered the market index averaged £93.43. What it sent out was worth £90.25 a megawatt hour at that same index, 0.97 times the average. What it took in was worth £95.39, 1.02 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.

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

All three measured lineswhole fleet, £/kW/yr97th 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.

BatteryMWHoursMeasured, per kW
Melksham Eastthis battery492h£107.3/kW/yr
York492h£53.0/kW/yr
Melksham West492h£37.3/kW/yr
Ilmer Lane BESS502h£35.7/kW/yr
SSE Salisbury492h£24.9/kW/yr
Swangate492h£9.5/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.