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Great Britain · the operating fleet

Tollgate Energy Storage

49 MW, about 49 MWh (1 hour, from the capacity market de-rating class) in Oxfordshire, Surrey and Sussex. Everything on this page is read from published data for the 364 days to 11 November 2026, or is labelled as an estimate.

What it is

Registered power49 MW balancing mechanism registration
Storage duration1 hour capacity market de-rating class
Charging zoneOxfordshire, Surrey and Sussex
Connection siteWelwyn Hatfield
PostcodeAL4 0NY
Balancing mechanism unitE_TOLLB-1

Who owns it and who trades it

Traded byTollgate Energy Storage Ltdconfirmed, Elexon's register
Owned byTOLLGATE ENERGY STORAGE LIMITED
Owner established fromcapacity market registered holder
UltimatelyRNK UK Investments (Tokio Marine Holdings), managed by Low Carbon confirmed source

How we know. Companies House: Tollgate Energy Storage Ltd, the company that trades the battery, is controlled at 75% or more by Tollcux Finance Ltd, which is controlled by Tollcux Investments Ltd, which is controlled by RNK UK Investments Ltd, all care of Low Carbon Ltd; RNK UK Investments is controlled by Tokio Marine Holdings since 15 May 2025, after Nippon Koei and then ID&E Holdings. Built as a Nippon Koei and Low Carbon project with TMEIC batteries.

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 is built from

Battery systemTMEIC, battery procurement (two 49.5 MW systems, Tollgate and Cuxton)
Engineering and constructionNippon Koei Energy Europe (EMS and delivery)

From published documents, not from any register: supplier and contractor project pages, owner announcements and the trade press. Confidence: confirmed. Checked 2026-10-06. source 1. Fields not shown are not published anywhere we have found, and we do not guess them.

What it earned

Line364 days to 11 November 2026
Balancing mechanism£99k
Response and reserve auctions auction implied£1.5m
Capacity market£373k
Three lines together£2.0m

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 15,783 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 20 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. 358 days to 5 November 2026, 42 of them still provisional in Elexon's settlement runs. Method and caveats

LineMWh or £
Metered export, what crossed the meter out16,769 MWh
Metered import, what crossed the meter in19,936 MWh
Equivalent full cycles, everything sent out over one full charge342 over 358 days, 349 a year at that rate
Apparent meter to meter efficiency84%, an ordinary battery: round trip losses alone
Balancing offers accepted1,105 MWh
Balancing bids accepted637 MWh
Position outside balancing, export16,400 MWh
Position outside balancing, import20,035 MWh
Of which expected response delivery, net386 MWh 1,982 out, 1,596 in
Traded position, net−4,022 MWh 15,523 out, 19,545 in
Traded position at the market index, sold£2.0m
Traded position at the market index, bought£1.7m
Traded position, net, at the index£339k
Response delivery, net, at the imbalance price£22k £33k at the index
Balancing and outside balancing together£464k £9.65/kW/yr

This battery connects to a distribution network. For such a unit the volumes Elexon publishes are settlement volumes: the site's own meter multiplied by the network operator's line loss factor for that half hour. The factor is usually within a few per cent of one, so the megawatt hours, cycles and efficiency above can sit a little above or below what crossed the site's meter. The money is settled on the same adjusted volumes. Method and caveats

When it moved, against when power was dear

Across every half hour this unit was metered the market index averaged £104.66. What it sent out was worth £130.53 a megawatt hour at that same index, 1.25 times the average. What it took in was worth £86.31, 0.82 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 637 MWh of accepted bids it paid an average of £95.86 a megawatt hour. The market index averaged £146.52 across those same half hours, so it bought back at £50.66 a megawatt hour below the going price.

Price it paidVolumeAverageCash
below zero28 MWh−£24.35£675 received
£0 to £2556 MWh£13.97£786
£25 to £5057 MWh£38.67£2k
£50 to £7559 MWh£66.14£4k
£75 to £10089 MWh£89.45£8k
above £100348 MWh£134.74£47k

On 28 MWh the price was below zero: NESO paid this unit an average of £24.35 a megawatt hour to take energy, £675 in all. That is a constrained network with more generation on it than it can move.

The other direction, offers, is much smaller here: 1,105 MWh where NESO asked for more, paid at an average of £147.70 against an index of £89.78.

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/yr9th percentile103 units
Balancing incomeEngland and Wales peer group7th percentile75 units
Balancing income1.0 hour duration cohort7th percentile29 units
All three measured lineswhole fleet, £/kW/yr57th percentile234 units
Energy sent outhours at full power7th percentile101 units
Energy taken inhours at full power1st percentile101 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
Pillswood 2 Battery Storage501.5h£48.3/kW/yr
Tollgate Energy Storagethis battery491h£41.1/kW/yr
Cowley491.5h£31.2/kW/yr
Clay Tye Farm 1 Battery Storage501h£23.3/kW/yr
Red Scar491h£16.0/kW/yr
Wickham Market491h£6.3/kW/yr

In its distribution register

The distribution register of UK Power Networks lists this site as Tollgate Farm, 50 MW, connected on 3 May 2023. Matched on a site word in common, 0 km apart.

See it on the Development Atlas

From each operator’s embedded capacity register, read every Monday. How the registers are linked to the units that trade.

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.

Need every battery at once? The register is not offered for automated download, and bulk access is by request at hello@vitreouslabs.com.