Vitreous LabsEnergy transparency

E_BERKB-1

44 MW 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.

Part of Berkeley BESS, one of 2 balancing units at one site totalling 96 MW. This page is the E_BERKB-1 unit alone.

This registration has been superseded. The battery here has sold as Berkeley BESS since 18 March 2026; this code, sold by Arenko Cleantech Limited, last appeared on 8 September 2025. The page stays for the record, and the unit is no longer counted in fleet totals or ranked in the league.

What it is

Registered power44 MW balancing mechanism registration
Charging zoneCotswold
Connection siteStroud
PostcodeGL13 9PP
Balancing mechanism unitE_BERKB-1

Who owns it and who trades it

Traded byEDF Energy Customers Limitedruns several sitesconfirmed, Elexon's register
Owned bynot published anywhere we can read
UltimatelyVoltwise Power (Sandbrook Capital) confirmed source

How we know. The register names no owner. The capacity market holds a site called BERKB1 belonging to Voltwise Power Holdings Limited 830 metres away, which is this unit's own balancing code.

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£0
Response and reserve auctions auction implied£0
Capacity marketno agreement we can attach
Three lines together£0

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 no frequency response contract in the window, so the whole position is treated as traded. 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. 170 days to 18 March 2026. Method and caveats

LineMWh or £
Metered export, what crossed the meter out8,869 MWh
Metered import, what crossed the meter in10,579 MWh
Equivalent full cycles, everything sent out over one full charge·
Apparent meter to meter efficiency84%, an ordinary battery: round trip losses alone
Balancing offers accepted0 MWh
Balancing bids accepted0 MWh
Position outside balancing, export8,869 MWh
Position outside balancing, import10,579 MWh
Valued at the market index, sold£804k
Valued at the market index, bought£797k
Outside balancing, net, at the index£7k
Balancing and outside balancing together£7k £0.33/kW/yr

When it moved, against when power was dear

Across every half hour this unit was metered the market index averaged £81.89. What it sent out was worth £90.64 a megawatt hour at that same index, 1.11 times the average. What it took in was worth £75.36, 0.92 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.

Checks this unit did not pass cleanly. Published anyway, because a flagged figure with its flag is more use than a blank.

  • only 170 of 364 days metered
  • the meter exceeded the 44.0 MW registration on 1 day between 2026-03-11 and 2026-03-11, peaking at 51 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

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
Gses 1 (GSET-07)451h£41.9/kW/yr
Hunningley Stairfoot BESS441h£37.0/kW/yr
Minety (AG-HLIM04)441h£36.3/kW/yr
Enderby452h£35.1/kW/yr
South Gloucestershire44not known£20.4/kW/yr
E_BERKB-1this battery44not known£0.0/kW/yr

Why every line reads zero

This registration was active in the response and reserve auctions between 31 March 2025 and 8 September 2025 and took £764k over its life. Its last award came before the year this page covers, and it has won nothing since.

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.