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 16 October 2026, or is labelled as an estimate.
What it is
| Registered power | 49 MW balancing mechanism registration |
| Storage duration | 1 hour capacity market de-rating class |
| Charging zone | Oxfordshire, Surrey and Sussex |
| Connection site | Welwyn Hatfield |
| Postcode | AL4 0NY |
| Balancing mechanism unit | E_TOLLB-1 |
Who owns it and who trades it
| Traded by | Tollgate Energy Storage Ltdconfirmed, Elexon's register |
| Owned by | TOLLGATE ENERGY STORAGE LIMITED |
| Owner established from | capacity market registered holder |
| Ultimately | RNK 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 system | TMEIC, battery procurement (two 49.5 MW systems, Tollgate and Cuxton) |
| Engineering and construction | Nippon 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
| Line | 364 days to 16 October 2026 |
|---|---|
| Balancing mechanism | £110k |
| Response and reserve auctions auction implied | £1.5m |
| Capacity market | £374k |
| 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 15,743 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. 359 days to 11 October 2026, 45 of them still provisional in Elexon's settlement runs. Method and caveats
| Line | MWh or £ |
|---|---|
| Metered export, what crossed the meter out | 16,528 MWh |
| Metered import, what crossed the meter in | 19,685 MWh |
| Equivalent full cycles, everything sent out over one full charge | 337 over 359 days, 343 a year at that rate |
| Apparent meter to meter efficiency | 84%, an ordinary battery: round trip losses alone |
| Balancing offers accepted | 1,041 MWh |
| Balancing bids accepted | 491 MWh |
| Position outside balancing, export | 16,133 MWh |
| Position outside balancing, import | 19,841 MWh |
| Of which expected response delivery, net | 367 MWh 1,964 out, 1,597 in |
| Traded position, net | −4,074 MWh 15,263 out, 19,337 in |
| Traded position at the market index, sold | £1.9m |
| Traded position at the market index, bought | £1.5m |
| Traded position, net, at the index | £318k |
| Response delivery, net, at the imbalance price | £23k £32k at the index |
| Balancing and outside balancing together | £441k £9.15/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 £122.30 a megawatt hour at that same index, 1.26 times the average. What it took in was worth £80.11, 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 491 MWh of accepted bids it paid an average of £83.09 a megawatt hour. The market index averaged £137.83 across those same half hours, so it bought back at £54.74 a megawatt hour below the going price.
| Price it paid | Volume | Average | Cash |
|---|---|---|---|
| below zero | 43 MWh | −£25.31 | £1k received |
| £0 to £25 | 40 MWh | £15.27 | £609 |
| £25 to £50 | 58 MWh | £38.34 | £2k |
| £50 to £75 | 49 MWh | £66.63 | £3k |
| £75 to £100 | 80 MWh | £89.28 | £7k |
| above £100 | 221 MWh | £129.28 | £29k |
On 43 MWh the price was below zero: NESO paid this unit an average of £25.31 a megawatt hour to take energy, £1k in all. That is a constrained network with more generation on it than it can move.
The other direction, offers, is much smaller here: 1,041 MWh where NESO asked for more, paid at an average of £135.92 against an index of £75.96.
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/yr | 8th percentile100 units | |
| Balancing incomeEngland and Wales peer group | 6th percentile72 units | |
| Balancing income1.0 hour duration cohort | 7th percentile30 units | |
| All three measured lineswhole fleet, £/kW/yr | 57th percentile230 units | |
| Energy sent outhours at full power | 9th percentile98 units | |
| Energy taken inhours at full power | 2nd percentile98 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.
| Battery | MW | Hours | Measured, per kW |
|---|---|---|---|
| Pillswood 2 Battery Storage | 50 | 1.5h | £59.4/kW/yr |
| Tollgate Energy Storagethis battery | 49 | 1h | £41.3/kW/yr |
| Cowley | 49 | 1.5h | £30.5/kW/yr |
| Clay Tye Farm 1 Battery Storage | 50 | 1h | £27.4/kW/yr |
| Red Scar | 49 | 1h | £16.5/kW/yr |
| Wickham Market | 49 | 1h | £6.2/kW/yr |
See it on the map
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.