​On 8 July 2025, solar generation in Great Britain hit 14 GW for the first time. For several hours that afternoon, solar was producing more electricity than gas, wind, and nuclear combined. Thats without including solar in the CfD scheme, which is set to bring 10 GW of solar online in the next few years.

That record output had a direct impact on battery trading. On 3 July, with solar peaking at 11.5 GW, the ME BESS GB index recorded £318/MW, 84% above the summer 2025 daily average. On 8 July, with solar at 14 GW, revenues fell to £155/MW, 10% below average. Solar is stretching intraday spreads on some days and compressing them on others, depending on how the output profile interacts with demand and wind.

Great Britain now has 21 GW of installed solar. The government wants 45 GW of total solar — rooftop and ground-mount combined — by 2030. That means more than doubling the fleet in five years, and the effects of CfD and non-subsidised solar on wholesale price formation, battery revenues, and capture rates will only intensify. Here is how we got here.

For further information on this topic, reach out to the author — zach@modoenergy.com

Key takeaways - solar buildout in three phases