Sembcorp (Wilton BESS) Ltd
Sells into the markets for 3 units at 3 sites, 150 MW together, over the 364 days to 27 September 2026. Everything here is measured from published settlement and auction results; wholesale trading is invisible for every optimiser, not just this one. Elexon's balancing mechanism register names it on every one of them.
The book
| Balancing mechanism, paid to discharge | £301k |
| Balancing mechanism, paid out to charge | −£255k |
| Response and reserve auctions | £6k |
| Capacity market | £0 |
| Income across the book, per kilowatt | £2.06/kW/yr fleet 42.17 |
| Median unit, all three lines | £1.98/kW/yr |
| Hours at full power, sent out | 16 h/yr |
| Hours at full power, taken in | 15 h/yr |
What the book is made of
Performance follows portfolio shape as much as skill: a Scottish, long duration book does a different job from an English one hour book, so the mix belongs beside the money, not in a footnote.
Duration, by megawatt
Region, by megawatt
Every unit it sells for
| Unit | MW | Balancing | Standing ready | CM | £/kW/yr |
|---|---|---|---|---|---|
| Wilton BESS (LIONB-1) | 50 | £109k | £2k | — | 2.22 |
| Wilton BESS (LIONB-2) | 50 | £99k | — | — | 1.98 |
| Wilton BESS (LIONB-3) | 50 | £94k | £4k | — | 1.97 |
Attribution. A unit belongs to whoever the market registers as its seller today, so a book that changed hands mid year credits the whole year to the current seller. The exception is a battery that re-registered under a new code: it is counted once, under the code it runs on today, and where the earlier code sold through somebody else that seller keeps what it earned. We have recorded optimiser switches since 27 August 2026 and the record deepens from here. Corporate families are not joined: a platform selling through several registered entities appears as several rows on the optimiser list.