Revenues in Great Britain rose 55% to £70k/MW/year in June 2026, up from £45k/MW/year in May, though 8% below June 2025's £76k/MW/year. The rebound came from the return of wholesale volatility. Deep negative prices and the widest day-ahead spreads in over a year brought back the conditions batteries need, while a late-month heatwave drove the highest mid-year wholesale prices since the gas crisis in 2022. Both wholesale arbitrage and Frequency Response revenues climbed, while the Balancing Mechanism recovered from a negative May.

June also broke temperature records across Great Britain. The heat pushed up demand and, over a couple of days in late June, drove sharp divergences between the day-ahead, intraday, and Balancing Mechanism markets. June 23rd saw the highest single-day BESS revenue since January 2025.

For subscribers to Modo Energy's Research, this article will also cover:

• A breakdown of revenue changes across each service
• Why a summer heatwave spiked intraday prices one day and day-ahead prices the next
• Why Balancing Mechanism revenues recovered from May
• Frequency Response prices rising across every service
• A data download of all charts

Revenues rise in major services

June's revenue stack was wholesale-export led, a contrast to the wholesale-import, Balancing Mechanism-export bias seen earlier in the year. Wholesale revenues rose to £30k/MW/year, up £11k from May and were the biggest contributor to total revenues.

Frequency Response added £20k/MW/year, up £10k, as clearing prices rose across every service. The Balancing Mechanism recovered to £5k/MW/year, a £6k swing from May's negative £1k. Reserve revenues rose £2k to £4k/MW/year. Capacity Market held at £7k/MW/year, and Imbalance fell £3k to £4k/MW/year.

Wholesale Market revenues

Day-ahead spreads jumped to £90/MWh

Average daily day-ahead spreads widened to £90/MWh in June, doubling from £48/MWh in May and the widest in over a year. Intraday spreads rose to £107/MWh from £70/MWh. The jump reversed the compression seen through late spring and restored the volatility battery revenues rely on.