Quarterly GB BESS Index — 2025Q4-2026Q3
Revenue per megawatt for Great Britain's grid batteries over the last four quarters, worked out from the public settlement and auction records. No licensed benchmark behind it. Every rule disclosed.
Trailing year, trading-position basis
£43.1k/MW·yr
Trailing year, floor basis
≥£42.1k/MW·yr
Wholesale, trading position (headline)
£17.9k/MW·yr
Wholesale, measured floorᶠ
£16.9k/MW·yr
BM, 2026Q3
net −£11.7k/MW·yr
£/MW·yr is pounds per megawatt of battery per year, before operating costs. ᶠ marks a figure that contains the floor, our cautious wholesale reading from metered volumes alone. BM is the Balancing Mechanism. The totals and the two wholesale figures cover the trailing year, and the totals include the Capacity Market; the BM figure is 2026Q3 alone.
2026Q3, July to September 2026, was a wholesale quarter. The floorᶠ alone was 86% of measured revenue; frequency response and reserve took 36%. The two add to more than 100% because the Balancing Mechanism's net cashflow was negative: batteries paid more for the energy they were instructed to take on than they were paid for the energy they put out on instruction. Where a battery sits matters. Net Balancing Mechanism cashflow ran from +£22k to −£80k per megawatt a year between grid zones. At the negative end batteries are paying to charge when they are told to; the value of that energy shows up in the wholesale line, so it is not a loss. The top quarter of units sit tens of thousands of pounds per megawatt above the median. The report shows where.
Every rule is written down in the report, so you can check me rather than take my word for it.
Day-ahead prices: N2EX GB Day-Ahead Price, published by NESO — Supported by National Energy SO Open Data — https://www.neso.energy/data-portal/day-ahead-power-exchange-prices-nordpool. The hourly series itself is not republished here.
inside: the four streams · the spread between the best units and the rest · 1h, 2h and 4h · location · how every number is built, and every known limitation
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