Willoughby

What it is

Where the duration comes from. No owner or builder publishes a duration for Willoughby. Pulse Clean Energy, which owns it, announced it in July 2023 as one of four batteries, with Briton Ferry, Tir John and Flatworth, holding more than 100 MWh together (Solar Power Portal, 10 July 2023, solarpowerportal.co.uk). This site holds Pulse's four at 79 MW in all, so they cannot all be one hour batteries, which is what the capacity market class gave each of them and what this page showed until 25 October 2026. Willoughby's own declarations to NESO were the steadiest of all the British batteries this site read on 24 October 2026: across 511 half hours from 14 to 24 October 2026 the energy it held plus its room to charge was 29 MWh at the middle and 30 MWh in the fullest 5%, about 1.5 hours on its 20 MW. This page takes 1.5 hours from those declarations. It is the battery's own statement to the grid operator, not a figure its owner has published, and it would change if Pulse publishes one. Every megawatt hour figure on this site for this battery is worked from 1.5 hours.

Who owns it and who trades it

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. This unit is registered only in the response and reserve auctions, so the seller is the participant NESO's auction results name, and Elexon's register carries no entry to check it against. How we tell them apart

What it earned

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, estimated from metered peers

Elexon publishes no metered output for this battery. Its balancing registration, V__BHABI013, is a virtual unit registered by the company that trades it, and this site reads no meter for it, so nothing can be derived for it. What can be said is what its peers did: 8 units of about 1.5 hours in England and Wales, metered, earned between £17.25 and £46.02 per kilowatt a year with the balancing legs and the position outside the balancing mechanism together, £34.81 at the median. Applied to this unit's 20 MW that is £696k, in a range of £345k to £920k. An estimate from other batteries, never this one's figure. Method

Where it stands

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.

In its distribution register

The distribution register of National Grid Electricity Distribution lists this site as Willoughby bess, 35 MW, connected on 17 January 2023. Matched on the same owner, 1 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.