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Great Britain · the operating fleet

Atherton

30 MW, about 75 MWh (2.5 hours, from the capacity market de-rating class) in South Lancashire, Yorkshire and Humber. Everything on this page is read from published data for the 364 days to 16 October 2026, or is labelled as an estimate.

What it is

Registered power30 MW response and reserve auction registration
Storage duration2.5 hours capacity market de-rating class
Charging zoneSouth Lancashire, Yorkshire and Humber
Connection siteWigan
PostcodeM46 0RY
Balancing mechanism unit2__GFLEX008 a supplier unit registered by the company that trades it; its balancing actions are counted on this page

Who owns it and who trades it

Traded byFlexitricity Limitedruns several sitesconfirmed, Elexon's register
Owned byPULSE CLEAN ENERGY SPV CAVENDISH LIMITED
Owner established fromcapacity market registered holder
UltimatelyPulse Clean Energy confirmed source

How we know. Pulse Clean Energy UK Limited was Green Frog Power 214 Limited until December 2021 and Pulse Clean Energy Limited was Green Frog Power Limited until January 2022. Both sit under Pulse Clean Energy Topco Limited.

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 16 October 2026
Balancing mechanism£508k
Response and reserve auctions auction implied£274k
Capacity market£197k
Three lines together£978k

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 9,274 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 10 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. 359 days to 11 October 2026, 45 of them still provisional in Elexon's settlement runs. Method and caveats

LineMWh or £
Metered export, what crossed the meter out21,258 MWh
Metered import, what crossed the meter in25,013 MWh
Equivalent full cycles, everything sent out over one full charge283 over 359 days, 288 a year at that rate
Apparent meter to meter efficiency85%, an ordinary battery: round trip losses alone
Balancing offers accepted7,059 MWh
Balancing bids accepted5,539 MWh
Position outside balancing, export20,417 MWh
Position outside balancing, import25,692 MWh
Of which expected response delivery, net−5,020 MWh 1,423 out, 6,443 in
Traded position, net−255 MWh 22,165 out, 22,420 in
Traded position at the market index, sold£2.7m
Traded position at the market index, bought£1.6m
Traded position, net, at the index£1.1m
Response delivery, net, at the imbalance price−£681k −£655k at the index
Balancing and outside balancing together£875k £29.67/kW/yr

When it moved, against when power was dear

Across every half hour this unit was metered the market index averaged £97.34. What it sent out was worth £122.58 a megawatt hour at that same index, 1.26 times the average. What it took in was worth £73.46, 0.76 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 5,539 MWh of accepted bids it paid an average of £67.05 a megawatt hour. The market index averaged £109.80 across those same half hours, so it bought back at £42.75 a megawatt hour below the going price.

Price it paidVolumeAverageCash
below zero497 MWh−£17.39£9k received
£0 to £25662 MWh£11.73£8k
£25 to £50851 MWh£37.88£32k
£50 to £75981 MWh£60.85£60k
£75 to £100906 MWh£87.73£79k
above £1001,642 MWh£122.35£201k

On 497 MWh the price was below zero: NESO paid this unit an average of £17.39 a megawatt hour to take energy, £9k in all. That is a constrained network with more generation on it than it can move.

The other direction, offers, is much smaller here: 7,059 MWh where NESO asked for more, paid at an average of £121.44 against an index of £79.83.

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

  • the meter exceeded the 30.0 MW registration on 1 day between 2026-03-10 and 2026-03-10, peaking at 34 MW export and 38 MW import: more than this battery can do, so another asset on the same meter, a commissioning period, or a settlement run error

Where it stands

All three measured lineswhole fleet, £/kW/yr59th percentile230 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
Mannington292h£146.7/kW/yr
Welkin Mill332h£118.3/kW/yr
Wormald Green BESS332h£67.5/kW/yr
Athertonthis battery302.5h£32.7/kW/yr
West Bradford292.5h£29.6/kW/yr
North Tawton BESS322h£13.0/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.