Record solar generation helped European electricity systems absorb a difficult summer period in which extreme temperatures lifted demand while drought constrained hydro and nuclear generation.
EU solar plants produced 52 TWh in June before reaching a record 55 TWh in July, covering roughly one-quarter of electricity consumption in both months.
The output came as temperatures exceeded 40C across parts of Europe, driving stronger air-conditioning demand while worsening hydrological conditions.
Hydropower production between May and July fell to its lowest level for that three-month period in at least a decade.
Nuclear generation also became vulnerable to high temperatures and low river flows. Both reactors at Romania’s Cernavoda nuclear plant were taken offline as Danube levels fell, while Hungary reduced output at Paks and temporarily shut several units.
France faced around 29 GW of unavailable nuclear capacity on 12 July. Scheduled maintenance accounted for much of this, although environmental restrictions and forced outages were estimated to have affected as much as 11 GW.
Wholesale prices responded rapidly to the tightening balance. During heatwave periods in late June and early July, average Hungarian electricity prices were 119% above comparable days in the previous week. France rose 44%, Italy 13% and Spain 7%.
Solar softened much of the daytime pressure, but the system became significantly tighter after sunset. Prices rose sharply during early evening hours as photovoltaic production disappeared while cooling demand remained elevated.
The summer therefore highlighted a growing European flexibility problem. Solar can increasingly protect the midday market from scarcity, but storage, hydro and other dispatchable capacity are becoming more valuable during the evening transition when renewable output declines fastest.
