During the June-July 2026 heatwaves, solar generation rose up to 17 % on hot days while electricity demand jumped as much as 28 % in Italy, creating spot-price spikes of up to 119 % in Hungary. Grid operators say the combined surge left evening-peak supply gaps that can only be closed by large-scale battery storage.
Solar generation spikes
Ember's analysis, cited by Euronews Business, found that on heatwave days solar output was up to 17 % higher than on non-heatwave days across Europe. The increase was observed throughout the region, from France to Spain, and reflects the abundant sunshine that accompanied the late-June and early-July temperature peaks.
Demand and price surges
Daily electricity demand rose by 28 % in Italy, 23 % in Hungary, 14 % in France and 13 % in Spain when compared with pre-heatwave days. Spot-price increases were most pronounced in Hungary, where average daily prices surged 119 % relative to the weeks preceding the heatwave; France saw a 44 % rise, Italy 13 % and Spain 7 %.
| Country | Demand increase | Price surge | Solar output increase* |
|---|---|---|---|
| France | 14 % | 44 % | up to 17 % (overall) |
| Hungary | 23 % | 119 % | up to 17 % (overall) |
| Spain | 13 % | 7 % | up to 17 % (overall) |
| Italy | 28 % | 13 % | up to 17 % (overall) |
*Country-specific solar increase not detailed in the source; Ember reports a maximum 17 % rise across the region.
Why storage matters
Senior energy analyst Chris Rosslowe warned that "the real challenge starts after sundown, when solar output falls but demand remains high". ENTSO-E's 2026 summer outlook echoes this concern, stating that without sufficient utility-scale battery storage, evening-peak deficits could threaten grid stability.
Looking ahead
National grid operators are now accelerating procurement programmes for large-scale batteries, and the European Commission is expected to review storage targets in its upcoming energy-security strategy. How quickly new capacity can be installed will determine whether Europe can smooth out evening-peak gaps and avoid further price spikes.