Vitreous LabsEnergy transparency

Glassenbury extension

9 MW in Essex and Kent. Everything on this page is read from published data for the 364 days to 23 September 2026, or is labelled as an estimate.

What it is

Registered power9 MW response and reserve auction registration
Charging zoneEssex and Kent
Connection siteTunbridge Wells
PostcodeTN17 2QJ
Balancing mechanism unitnone found under the codes we search

Who owns it and who trades it

Traded byHABITAT ENERGY LIMITEDruns several sitesauction results, unchecked
Owned byGLASSENBURY BATTERY STORAGE LIMITED
Owner established fromcapacity market registered holder
UltimatelyGresham House Energy Storage Fund confirmed source

How we know. The registered office of each company names Gresham House Asset Management, read company by company on 31 August 2026. The address alone would not settle it, because 875 companies sit at 5 New Street Square; the care of line naming the manager is the discriminator.

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 earned

Line364 days to 23 September 2026
Balancing mechanismnot published
Response and reserve auctions auction implied£0
Capacity market£1.4m
Three lines together£1.4m

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: 8 units of about unknown hours in England and Wales, metered, earned between £-10.55 and £3.96 per kilowatt a year with the balancing legs and the position outside the balancing mechanism together, £2.14 at the median. Applied to this unit's 9 MW that is £19k, in a range of −£95k to £36k. An estimate from other batteries, never this one's figure. Method

Where it stands

All three measured lineswhole fleet, £/kW/yr46th percentile197 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. How long this battery can run for is not published, so duration is not used to choose them. Same market, same rules, same weather.

BatteryMWHoursMeasured, per kW
Glassenbury extensionthis battery9not known£152.7/kW/yr
Winchester (WNCRB-1)91h£90.4/kW/yr
Kings Barn Farm9not known£31.4/kW/yr
Ecotricity (SMART GRID)92h£9.3/kW/yr
Winchester (EDFE-11)9not known£5.3/kW/yr
UF_FLX029not known£0.0/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.