Vitreous LabsEnergy transparency

SSE Salisbury

49 MW, about 98 MWh (2 hours, 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 power49 MW response and reserve auction registration
Storage duration2 hours capacity market de-rating class
Charging zoneSomerset and Wessex
Connection siteWiltshire
PostcodeSP2 0BL
Balancing mechanism unitnone found under the codes we search

Who owns it and who trades it

Traded bySSE ENERGY SUPPLY LIMITEDconfirmed, Elexon's register
Owned bySSE BATTERY SALISBURY LIMITED
Owner established fromcapacity market registered holder
UltimatelySSE confirmed source

How we know. SSE's own battery storage pages.

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 systemWärtsilä
Entered operation2024-04 (full operations; first auction in our archive 8 April 2024 agrees)
Container count26 battery units

From published documents, not from any register: supplier and contractor project pages, owner announcements and the trade press. Confidence: confirmed. Checked 2026-08-31. source 1. Fields not shown are not published anywhere we have found, and we do not guess them.

What it earned

Line364 days to 27 September 2026
Balancing mechanismnot published
Response and reserve auctions auction implied£473k
Capacity market£743k
Three lines together£1.2m

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 4,243 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. 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 out37,239 MWh
Metered import, what crossed the meter in44,946 MWh
Equivalent full cycles, everything sent out over one full charge380 over 346 days, 401 a year at that rate
Apparent meter to meter efficiency83%, plausible: losses plus a standing load that is material against a modest throughput
Balancing offers accepted0 MWh
Balancing bids accepted0 MWh
Position outside balancing, export37,239 MWh
Position outside balancing, import44,946 MWh
Of which expected response delivery, net−382 MWh 3,975 out, 4,357 in
Traded position, net−7,324 MWh 35,475 out, 42,799 in
Traded position at the market index, sold£3.9m
Traded position at the market index, bought£3.3m
Traded position, net, at the index£557k
Response delivery, net, at the imbalance price−£57k −£31k at the index
Balancing and outside balancing together£500k £10.75/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 £109.37 a megawatt hour at that same index, 1.17 times the average. What it took in was worth £77.64, 0.83 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.

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

All three measured lineswhole fleet, £/kW/yr39th percentile229 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
Melksham East492h£107.3/kW/yr
York492h£53.0/kW/yr
Melksham West492h£37.3/kW/yr
Ilmer Lane BESS502h£35.7/kW/yr
SSE Salisburythis battery492h£24.9/kW/yr
Swangate492h£9.5/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.