CECadence
Quarterly GB BESS Index — measured fleet revenue
A Compounding Energy product
cadence.compoundingenergy.com
Trailing four quarters
2025Q2-2026Q1
Active GB BESS fleet
6.2 GW · 149 BMUs
Total measured revenue
£35.2k/MW·yr

Revenue by stream (per MW·yr)

Frequency response£18.6k
56.3%
Balancing Mechanism£13.1k
39.9%
Capacity Market£2.2k
Wholesale (metered-at-MID floor)£1.3k
3.9%

Active-MW-day weighted over the 2025Q2-2026Q1 window across the metered GB battery fleet (168 BMUs / 6.7 GW registered). Frequency response remains the largest stream; the Balancing Mechanism is rising as FR saturates.

By duration class (per MW·yr)

ClassBMFR CMcycles/dayspread
1h£8.5k£20.1k£2.7k0.8026.0%
2h£12.3k£15.2k£4.8k0.9223.2%
4h£-1.4k£3.9k0.2822.3%

4h units are net BM payers (value lands in cheap charging); no 8h units exist in the GB fleet yet. Cycles/day measured from metered throughput.

Through the year (per quarter)

2h class2025Q22025Q32025Q42026Q1
Active fleet (GW)4.75.56.16.2
Active BMUs117130143149
Cycles/day0.940.810.911.04

How to read this

All figures are measured from public primary data — no third-party benchmark licence. Revenue is per MW of active capacity per year, active-MW-day weighted. The wholesale line is a metered-at-MID floor (metered volume × Elexon market index), not traded-position revenue — it embeds BM/FR throughput and losses, so it is a lower bound and reported separately. Balancing Mechanism from EBOCF bid-offer cashflows; Frequency Response from NESO EAC clearing × executed; Capacity Market on an initial-auction basis (awarded de-rated obligations x acquiring-auction clearing prices, delivery years overlap-weighted into the window; postcode fuzzy join to re…). Initial settlement; figures revise.