Vitreous LabsEnergy transparency

Nursling Battery Storage

48 MW, about 48 MWh (1 hour, from the capacity market de-rating class) in Somerset and Wessex. 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 power48 MW balancing mechanism registration
Storage duration1 hour capacity market de-rating class
Charging zoneSomerset and Wessex
PostcodeSO16
Balancing mechanism unitT_NURSB-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
UltimatelyDowning confirmed source

How we know. Downing's own portfolio names Nursling Energy Two Limited, which the connection register carries as Nursling Tertiary at Nursling 400kV, built. A Downing Group member joined both Nursling boards in July 2026. Note that Downing Corporate Finance ceased to control the parent in March 2019: it is now held between Bagnall Energy Limited and CCPEPF UK Intermediate Limited, each between a quarter and a half, and both file that they have no registrable controller. Downing is the manager here, and the register names no single controlling company.

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£86k
Response and reserve auctions auction implied£1.3m
Capacity market£87k
Three lines together£1.5m

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 14,198 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 16 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 out10,173 MWh
Metered import, what crossed the meter in13,073 MWh
Equivalent full cycles, everything sent out over one full charge212 over 346 days, 224 a year at that rate
Apparent meter to meter efficiency78%, plausible: losses plus a standing load that is material against a modest throughput
Balancing offers accepted3,904 MWh
Balancing bids accepted4,771 MWh
Position outside balancing, export10,313 MWh
Position outside balancing, import12,346 MWh
Of which expected response delivery, net−911 MWh 2,194 out, 3,105 in
Traded position, net−1,122 MWh 9,816 out, 10,938 in
Traded position at the market index, sold£1.0m
Traded position at the market index, bought£858k
Traded position, net, at the index£192k
Response delivery, net, at the imbalance price−£110k −£90k at the index
Balancing and outside balancing together£179k £3.93/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 £106.91 a megawatt hour at that same index, 1.14 times the average. What it took in was worth £78.41, 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 4,771 MWh of accepted bids it paid an average of £73.05 a megawatt hour. The market index averaged £97.73 across those same half hours, so it bought back at £24.68 a megawatt hour below the going price.

Price it paidVolumeAverageCash
below zero293 MWh−£23.08£7k received
£0 to £25300 MWh£10.17£3k
£25 to £50422 MWh£38.71£16k
£50 to £751,241 MWh£65.97£82k
£75 to £1001,513 MWh£87.32£132k
above £1001,003 MWh£121.57£122k

On 293 MWh the price was below zero: NESO paid this unit an average of £23.08 a megawatt hour to take energy, £7k in all. That is a constrained network with more generation on it than it can move.

The other direction, offers, is much smaller here: 3,904 MWh where NESO asked for more, paid at an average of £114.12 against an index of £81.70.

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/yr31st percentile98 units
Balancing incomeEngland and Wales peer group22nd percentile70 units
Balancing income1.0 hour duration cohort48th percentile24 units
Balancing incomebatteries sold by EDF Energy Customers Limited33rd percentile13 units
All three measured lineswhole fleet, £/kW/yr60th percentile229 units
Energy sent outhours at full power34th percentile96 units
Energy taken inhours at full power31st 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 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
Richborough Energy Park 2501h£36.6/kW/yr
Cowley491h£31.6/kW/yr
Nursling Battery Storagethis battery481h£30.6/kW/yr
Clay Tye Farm 1 Battery Storage501h£29.8/kW/yr
Red Scar491h£13.7/kW/yr
Wickham Market491h£6.3/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.