Vitreous LabsEnergy transparency

Hutton Battery Storage

49 MW in Essex and Kent. 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 balancing mechanism registration
Charging zoneEssex and Kent
Connection siteHutton
PostcodeCM13 1BZ
Balancing mechanism unitE_ARNKB-2

The registered capacity is in doubt. Elexon registers this unit at 49 MW. Three other records point to about 10 MW. The planning database lists it as Hutton Battery Storage (Lower Road), 10 MW, operational, Gore Street and Flexitricity. Gore Street's own portfolio lists Lower Road at 10 MW. And in 359 days of Elexon's metered output to 12 September 2026 no half hour averaged more than 5.9 MW in either direction. We keep the registered 49 MW and work every per kilowatt figure on this site from it until a document settles it. On 10 MW, this unit's income of £5.92 per kW per year would be £29.01.

Who owns it and who trades it

Traded byFlexitricity Limitedruns several sitesconfirmed, Elexon's register
Owned byGSES 1 LIMITED
Owner established fromcapacity market registered holder
UltimatelyGore Street Energy Storage Fund confirmed source

How we know. GSES 1 Limited is held at three quarters or more by Gore Street Energy Storage Fund Plc, and has been since February 2018.

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£1k
Response and reserve auctions auction implied£288k
Capacity market£20k
Three lines together£309k

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 16,344 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 17 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 out677 MWh
Metered import, what crossed the meter in889 MWh
Equivalent full cycles, everything sent out over one full charge·
Apparent meter to meter efficiency76%, worth investigating: more than ordinary losses
Balancing offers accepted6 MWh
Balancing bids accepted2 MWh
Position outside balancing, export676 MWh
Position outside balancing, import892 MWh
Of which expected response delivery, net−21 MWh 333 out, 354 in
Traded position, net−196 MWh 445 out, 641 in
Traded position at the market index, sold£47k
Traded position at the market index, bought£55k
Traded position, net, at the index−£8k
Response delivery, net, at the imbalance price−£5k −£3k at the index
Balancing and outside balancing together−£12k £-0.27/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 £104.71 a megawatt hour at that same index, 1.12 times the average. What it took in was worth £85.85, 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.

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 2 MWh of accepted bids it paid an average of £48.15 a megawatt hour. The market index averaged £74.43 across those same half hours, so it bought back at £26.28 a megawatt hour below the going price.

Price it paidVolumeAverageCash
£25 to £502 MWh£40.81£72

The other direction, offers, is much smaller here: 6 MWh where NESO asked for more, paid at an average of £183.26 against an index of £107.75.

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/yr1st percentile98 units
Balancing incomeEngland and Wales peer group1st percentile70 units
All three measured lineswhole fleet, £/kW/yr17th percentile229 units
Energy sent outhours at full power1st percentile96 units
Energy taken inhours at full power1st 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. 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
Melksham East492h£107.3/kW/yr
Roosecote BESS49not known£61.1/kW/yr
Tollgate Energy Storage494h£41.8/kW/yr
Cowley491h£31.6/kW/yr
Brentwood49not known£8.2/kW/yr
Hutton Battery Storagethis battery49not known£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.